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FAQ: (8/95) comp.lang.basic.visual.* VB/Win Frequently Asked Questions


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Posted-By: auto-faq 3.1.1.2
Archive-name: visual-basic-faq/windows

See reader questions & answers on this topic! - Help others by sharing your knowledge
Last-modified: 22-Aug-95

Covers VB 4.0 (briefly)

*** ATTENTION ***
A greatly expanded and updated version of this FAQ can now be found on the
WWW at http://home.sol.no/jansh/vb/default.htm - you are strongly encouraged
to refer to the WWW version.  The WWW version may be "ported" to text and
posted to the VB newsgroups, but there are no definate plans to do this at
this time.

Please send all feedback on this document to jansh@online.no (Jan S. Haugland)
Please don't send VB questions to the FAQ maintainers' private email account.
   

                   VISUAL BASIC FOR WINDOWS (VB/Win)
                 Frequently asked Questions & Answers
                            Section IX - B
   
   
   The following symbols indicates new & updated topics:
   
   [++] means topic is updated in this issue
   [**] means topic is new in this issue
   
   Hope this makes it easier for Our Regular Readers   ;-)
   
   
   
   TABLE OF CONTENTS:
   ******************
   
   A. PREFACE
   1. About this document
   2. Where to get the VB/Win FAQ [++]
   3. Kudos & comments
   
   B. GENERAL VISUAL BASIC QUESTIONS
   1. Does VB/Win make standalone .EXE files?
   2. What is the current version of Visual Basic for Windows? [++]
   3. Where can I get updated VB and other Microsoft files?
   4. Help! I am lost on ftp.microsoft.com.
   5. Where can I get good up-to-date information about VB? [++]
   6. WWW pages for VB! [**]
   7. Are there any examples of commercial applications built using
       Visual Basic?
   8. Limits of VB?
   
   C. COMMON VISUAL BASIC PROGRAMMING QUESTIONS
   1. What's the difference between MODAL and MODELESS forms? [++]
   2. When/Why should I use Option Explicit?
   3. Why does everybody say I should save in TEXT not BINARY?
   4. Is the Variant type slower than using other variable types?
   5. How do I make a text box not beep but do something else when I
       hit the Enter key?
   6. How do I implement an incremental search in list/dir/combo/file
       boxes?
   7. How do I get the Tab key to be treated like a normal character?
   8. How do I make an animated icon for my program?
   9. What is passing by reference?
   10. I get a "file not found" error on the IIF function when I
       distribute by program. Uh?
   11. Is there any way to pass a variable to a form apart from using
       global variables?
   12. How should dates be implemented so they work with other
       language and country formats?
   13. Can a VB application be an OLE server?
   14. How do I dial a phone number without using the MSCOMM VBX?
   15. I have [several] megabytes of memory. Why do I get an "out of
       memory" error? [++]
   16. How do I mimic a toggle button? [++]
   17. How do I get my application on top?
   18. Is there a way to break long lines in VB code?
   19. How do I remove/change the picture property of a control at
       design time?
   20. Is a [foo] VBX/DLL available as shareware/freeware?
   21. How do I make my applications screen-resolution independent?
   22. How do I do Peek and Poke and other low-level stuff? [++]
   23. Why doesn't "my string" & Chr$(13) do what I want?
   24. How do I prevent multiple instances of my program?
   25. How do I implement an accelerator key for a text box?
   26. How do I force a file dialogue box to reread the currect disk?
   27. How do I get the number of free bytes on a disk? [++]
   28. Data Control missing from toolbox when I use VB under NT 3.5.
       Huh?
   
   D. ADVANCED VISUAL BASIC PROGRAMMING ISSUES
   1. How do I tell when an application executed using the SHELL
       command is finished?
   2. How do I access C style strings?
   3. How can I change the printer Windows uses in code without using
       the print common dialog? How can I change orientation?
   4. Any tips for speeding up VB?
   5. How do I speed up control property access?
   6. How much gain in performance will I get if I write my number
       crunching routines in C instead of Visual Basic?
   7. How do you make a TEXTBOX read only? Or, how do I prevent the
       user from changing the text in a TEXTBOX?
   8. How can I create a VBX?
   9. How do you change the system menu (on the Control-Menu Box)?
   10. How do I play MID, WAV or other multimedia files?
   11. How can I call a 'hidden' DOS program from VB?
   12. How do I do drag & drop between applications?
   13. How do I use GetPrivateProfileString to read from INI files?
   14. How do I implement Undo?
   15. How do I create a window with a small title bar as in a
       floating toolbar?
   16. What is Pseudocode?
   17. Does VB support pointers to functions?
   18. How do I program the Novell NetWare API from VB?
   19. Visual Basic 4 news [**]
   20. How do you change the icon and otherwise manipulate the DOS
       box?
   21. How do I make the mouse cursor invisible/visible?
   22. How do I create controls dynamically (at run-time)?
   23. How do I set the Windows wallpaper at runtime?
   24. How do I call help files from a VB program? [**]
   
   E. CALLING THE WINDOWS API AND DLLs IN GENERAL
   1. What is the Windows API?
   2. How do I call a DLL?
   3. What about DLL calls that require callbacks?
   4. Tips for calling DLLs (such as the Windows API)
   
   F. VISUAL BASIC AND DATABASES
   1. Why can't I use an index with my VB accessed database?
   2. "Can't find installable ISAM" or Why does my compiled VB
       database app generate an error when it ran just fine in the
       design environment?
   3. Is the Access Engine and Visual Basic Pro good enough for
       database work?
   4. How do you avoid the "Invalid use of null" error when reading
       null values from a database?
   5. What is "NULL"?
   6. How can I access a record by record number?
   7. How about Access 2.0 compatibility?
   8. Tips for VB database programming:
   9. How come I get a "No Current Record" error when I use a a Data
       Control on an empty table?
   10. How can I speed up my VB database application?
   11. How do I get a bitmap picture in a field in an Access
       database?
   12. What is "Reserved Error -1209"?
   13. "Cannot perform operation. illegal.." with Paradox 3.5
       table(s)
   14. I'm getting error message "Reserved Error [-nnnn] ("There is
       no message for this error")" from Jet Engine 2.0. Huh?
   15. Why do I get "object not an array" when I try reference the
       fields of a global object variable which I have set to a table?
   16. Steps for securing an Access 2.0 database [**]
   
   G. DISTRIBUTING VISUAL BASIC APPLICATIONS
   1. What are some tips for using Setup Wizard?
   2. Are there restrictions on what I can distribute with my VB
       program?
   3. What alternatives to setup wizard do I have?
   4. Do I need to worry about users who have Progman replacements
       such as Norton Desktop and PC Tools?
   5. Can I distribute my app without vbrunXXX.dll?
   6. Why won't my setup program install commdlg.dll et. al.?
   7. Where do I install VBXs and DLLs?
   
   H. MISCELLANEOUS TIPS AND INFORMATION
   1. Multiple identifiers after the DIM statement can be confusing
   2. "Clean up" your project before final EXE compilation.
   3. Multiple END statements can be dangerous; or, The program that
       refused to terminate.
   4. What are the latest versions of the various files used by VB?
   
   I. VISUAL BASIC FOR APPLICATIONS (VBA)
   1. Any tips for VB/Win 3 programmers moving to VBA?
   2. Does VBA support VBXs?
   3. How do I access properties on my dialog boxes in VBA?
   4. How do I use database routines from Excel VBA?
   


A.   PREFACE

1.   About this document
   
   This document is a compilation of frequently asked questions and
   their answers about Visual Basic for Windows and Visual Basic for
   Applications which have been gathered from posts to the
   comp.lang.basic.visual.* newsgroups.  Although efforts have been
   made to find obvious errors, there is no guarantee that the
   information in this document is error-free. Neither the FAQ
   maintainer nor anyone else associated with this document assume
   ANY liability for the content or use of this document. If you find
   any errors, please report them to the address given below.
   
   This FAQ document is protected by international copyright
   regulations. Permission is granted to distribute it freely, both
   in electronic and written format, provided no charge is made.
   Also, do not make changes to this document without the consent of
   the maintainer. Usenet netiquette applies.

2.   Where to get the VB/Win FAQ [++]
   
   Most FAQs (including this one) are available at the anonymous ftp
   archive site "rtfm.mit.edu". All parts of the VB FAQ may be found
   here:
   
     ftp://rtfm.mit.edu/pub/usenet/comp.lang.basic.visual.misc/
   
   **Alternative FTP Sites**:
   The following are alternative sites to rtfm:
   
   North America: ftp.uu.net                     /usenet/news.answers
   Europe:        ftp.uni-paderborn.de           /pub/FAQ
                  ftp.Germany.EU.net             /pub/newsarchive/news.answers
                  grasp1.univ-lyon1.fr           /pub/faq
                  ftp.win.tue.nl                 /pub/usenet/news.answers
                  ftp.sunet.se                   /pub/usenet
   Asia:          nctuccca.edu.tw                /USENET/FAQ
                  hwarang.postech.ac.kr          /pub/usenet/news.answers
   
   (FYI:  "rtfm" stands for "Read The ******* Manual".  I kid you
   not!)
   [Andre van Meulebrouck (vanmeule@ils.nwu.edu)]
   
   You can also have the VB FAQs e-mailed to you by sending a message
   to
   "mail-server@rtfm.mit.edu" with ONLY the text
   
     send usenet/comp.lang.basic.visual.misc/*
   
   in the BODY of the message.
   
   Alternative mailservers for those who have no ftp access
     ftpmail@decwrl.dec.com or ftpmail@cs.uow.edu.au
     bitftp@pucc.princeton.edu or ftpmail@lth.se
     bitftp@dearn or to bitftp@vm.gmd.de (Europe only)
     ftpmail@ftp.uni-stuttgart.de
     ftpmail@grasp.insa-lyon.fr or ftpmail@ieunet.ie
     bitftp@plearn.edu.pl or bitftp@plearn (Europe)
     ftpmail@doc.ic.ac.uk or ftpmail@sunsite.unc.edu
   [thanks to Jakob Faarvang (jakobf@apexsc.com)]
   
   For all mailservers:
   Use the "index" command to get a list of files available at the
   site.
   Use the "help" command to get more detailed instructions.
   (NOTE: commands are in BODY of mail message!)
   
   Note that a Web-browser like Netscape or Microsoft Internet
   Explorer easily can access an ftp site, view and download files.
   The ftp address on the top of this point (ftp://...) is formatted
   for these browsers; just copy and paste the text directly into the
   "URL" line.
   
   There is currently work going on to make these available in HTML
   format (for Web-browsers). This work is done by Peter Millard
   <millard@buffnet.net>. Look at:
   
     http://www.buffnet.net/~millard/vblinks.htm
   
   or go directly to the copies of his HTML FAQ's (when finished!):
   
     http://www.buffnet.net/~millard/vbgenfaq.htm
     http://www.buffnet.net/~millard/vbdosfaq.htm
   

3.   Kudos & comments
   
   In this document, whenever a long line of code must be split into
   two or more lines of text in the code examples, a | symbol will
   precede each line which should be appended to the line above it.
   
   As the FAQ maintainer, I don't have time to explore all of the
   aspects of Visual Basic. Neither have I time or knowhow to
   personally answer direct technical questions thoroughly. I rely on
   your submissions to improve the quality and inclusiveness of this
   document. If you have found a VB hint, tip, trick, work-around,
   etc., please write it up and send it to me!
   
   Jan Steinar Haugland (jansh@online.no), VB/Win FAQ maintainer
   
   Please note that my first language is not English. You can safely
   ignore all typos, but if you find an error that is so embarrassing
   you can't help pulling your hair and screaming loud, just send me
   a note and I'll correct it quietly. OK?
   
   This document is a collective effort! I would like to thank all
   contributers, and also all those who have given constructive
   feedback. This FAQ is now widely distributed in the net community.
   
   Special thanks to the following people who have made many and
   invaluable contributions to the VB/Win FAQ:  Kris Nosack (the
   previous maintainer), Peter Millard, Nic Gibson, Mr. "D" (the
   anonymous contributor), George Tatge (gat@csn.org), Andy Dingley
   (dingbat@codesmth.demon.co.uk), Ayn Shipley (ashipley@hookup.net)
   and those I may have forgotten (sorry).
   
   John McGuire (jmcguire@jax.jaxnet.com), a longtime VB user,
   recently went through the FAQ and found lots of things worth his
   comments. Many of his corrections and suggestions are implemented
   throughout. Thanks!
   
   Everybody: Your help is GREATLY appreciated!

B.   GENERAL VISUAL BASIC QUESTIONS
  

1.   Does VB/Win make standalone .EXE files?
   
   VB/Win produces .exe files, but they are not standalone. All
   VB/Win programs must be distributed with the VBRUNx00.DLL file
   (where x is the major version number). This DLL must accompany all
   VB/Win programs, but only one such file should reside on every
   system where VB programs are used.

2.   What is the current version of Visual Basic for Windows? [++]
   
   VB/Win is just between version 3.0 and 4.0 as of writing this. 4.0
   is about to be released around the same time as Windows 95. This
   will contain both a 16-bit and a 32-bit (for NT and Win95) version
   of the developing environment and the intergrated compiler.

3.   Where can I get updated VB and other Microsoft files?
   
   Microsoft Software Library (MSL) is accessible from the following
   services:
   
   - Compu$erve
   
     GO MSL
     Search for <filename.EXE>
   
   - Microsoft Download Service (MSDL)
     Dial (206) 936-6735 to connect to MSDL
   
   - Internet (anonymous FTP)
     ftp ftp.microsoft.com
     Change to the \softlib\mslfiles directory
     (There are a LOT of files in this directory! It is not
     advisable to list all the files unless you have good time.
     See map below.)

4.   Help! I am lost on ftp.microsoft.com.
   
   You no longer have to be! The site have been reorganised, and
   you'll find the file DIRMAP.TXT in root (or whatever it's called
   on a 3.5 NT server). 

   NOTE: Directory and file names at ftp.microsoft.com are NOT case
   sensitive.
   
   Thanks to Richard Mason (richard@whitney.demon.co.uk) for the map
   he made for us before this long overdue reorganisation, and thanks
   for bringing this to my attention.

5.   Where can I get good up-to-date information about VB? [++]
   
   If you do any VB programming at all, you really should get the
   latest copy of the Microsoft Knowledge Base from one of the
   sources listed above!  The filename is VBKB.EXE or VBKB_FT.EXE for
   the version with full text searching. The Knowledge Base is a
   Windows help formatted document that is updated almost monthly.
   (Beware: The files are huge!)
   
   The EXE files on ftp.microsoft.com (and other places) are simple
   self-extracting files. They don't do any automatic updating of
   your system, just dump the file(s) inside them in the current
   directory on your disk, uncompressed and ready for use. Just
   replace the old files on your system with the new files (same
   name, usually).
   
   This FAQ (ahem) is a pretty good source as a digest of many of the
   VB issues that are discussed in the comp.lang.basic.visual.*
   newsgroups, but as such the information contained in this FAQ may
   not have been thoroughly tested or verified.
   
   For easier access to and use of this FAQ document, get the Windows
   Help file format FAQ doc by anonymous ftp to quasar.sba.dal.ca and
   look under /www/hlp. The .HLP version is made by Tim Roberts
   (TJR@SBACOOP.SBA.DAL.CA). This is HIGHLY RECOMMENDED.
   
   Dave McCarter puts out a nice Windows help formatted document
   called "Visual Basic Tips and Tricks". A good resource with
   information that isn't found in the Knowledge Base. It can be
   found by anonymous ftp to ftp.cica.indiana.edu
   /pub/pc/win3/programr/vbasic/ as VBTIPS??.ZIP, where '??' is the
   version number (yes, get the one with the highest number).
   
   [[ Mark Schoonover has started a monthly magazine called _VBWin
   Programmer's Magazine_ that is compiled around the Discussion of
   Microsoft Visual Basic and Related Issues mailing list. This
   magazine is available at the usual ftp sites like cica and at his
   BBS (619) 571-2846. Mark can be contacted at schoon@cts.com. It
   also has its own anonymous ftp site: ftp.cts.com in the
   /pub/schoon/VBWM.Issues directory. - ED: this appears to be down,
   alas. ]]
   
   Jakob Faarvang (jakobf@apexsc.com) maintains the useful CLBV
   Digest:
   
     http://www.apexsc.com/vb/clbv-digest/
   
   and
   
     ftp://ftp.apexsc.com/pub/cgvb/clbv-digest/
   
   Address for him regarding CLBV Digest is clbv-digest-
   editor@apexsc.com
   
   There is presently an effort to put together a VB code library so
   that VB users can share their best - and trickiest - programming
   work. The code library project is being spear headed by Hein Ragas
   who has managed to get a directory on CICA for code snippets to be
   deposited. Stayed tuned to comp.lang.basic.visual.misc for more
   information.
   
   There's a VISBAS-L mailing list for Visual Basic (Thanks to David
   Liden (DL9U@Virginia.EDU) for tracking it down for me when it
   moved). You can subscribe to this mailing list by sending an email
   to
   
     listserv@listserv.tamu.edu
   
   Place the following text in the *body* of the message (no, not the
   subject line):
   
     SUB VISBAS-L Real Name
   
   Where Real Name is just that, *your full real name* not your email
   address. Note that the traffic on this list may overflow your
   mailbox if you have a limited mail buffer. Expect around 40-50
   messages every weekday, a bit less during weekends. Also, to
   unsubscribe, do as above but with "UNSUB" in the body of the
   message to the LISTSERV address, *not* to the VISBAS-L list
   address itself (Believe it or not, we usually receive 2-3
   sub/unsub mails evur  day on the list, and we're really fed up!)
   Also, this mail server was split and a new list called VBDATA-L
   was made for Vb database (Jet) related topics. Same procedure for
   registering (SUB VBDATA-L Real Name).
   
   The address for the MS ACCESS listserver is
   listserv@indycms.bitnet or listserv@indycms.iupui.edu The list
   name is ACCESS-L. To subscribe, you follow the same procedure as
   for the other lists.
   
   Sorry, I know no mailservers or other Internet resources dedicated
   to VBA specifically. Send me any information you may have, and
   I'll bring it on.
   
   There are several Usenet newsgroups dedicated to MS Windows
   programming and use. In fact, far too many to list here :-)
   
   NOTE: PLEASE don't post VB stuff to comp.lang.visual. This group
   has *nothing* to do with Visual Basic, and the academics
   discussing "real" visual programming there are very, very annoyed
   at what they call "quasi-visual" stuff and postings about those
   languages to their group.
   
   If you have a Compu$erve account, you will find a forum for Visual
   Basic there, including some support from Microsoft:
   
   MS BASIC Forum    (GO MSBASIC)
   
   Message Sections Available:             Libraries Available:
    1 Forum News/Info                       1 MS Info and Index
    2 Setup Wizard/Kit                      2 Setup Wizard/Kit
    3 Data Access Objects                   3 Data Access Objects
    4 The Data Control                      4 The Data Control
    5 Programming Issues                    5 Programming Issues
    6 ODBC Connectivity                     6 ODBC Connectivity
    7 SQL Queries                           7 SQL Queries
    8 ProEdition Controls                   8 ProEdition Controls
    9 Calling API's/DLL's                   9 Calling API's/DLL's
   10 Using OLE/DDE                        10 VBWIN-ODBC/Database
   11 MSCOMM control                       11 MSCOMM control
   12 MCI/MAPI controls                    12 MCI/MAPI controls
   13 DOS Visual Basic                     13 DOS Visual Basic
   14 DOS and Mac Basic                    14 DOS and Mac Basic
   15 Suggestions/Mktg.                    15 Suggestions/Mktg.
   16 CDK                                  16 CDK
   17 3rd Party Products                   17 3rd Party Products
   
   There are magazines dedicated to VB. The best known is Fawcett
   Technical Publications' _Visual Basic Programmer's Journal_
   (VSPJ). Phone 800-848-5523 (for US credit card orders) or 303-541-
   0610 (int'l and US other orders), Email 74003.224@compuserve.com
   to Shirley Modric for subscription info. Address is 280 Second
   Street, Suite 200, Los Altos, CA 94022-3603 USA.
   
   From Randy Coates (rcoates@telerama.lm.com):
   I currently subscribe to "Inside Visual BASIC for Windows" from
   the Cobb Group.  Although it is a helpful monthly paper (about 14
   pages per publication), I find it to be overpriced when compared
   to VB Programmers Journal.  Here is the information anyway:
   Domestic $59/yr ($7.00 each); Outside US $79/yr ($8.50 each)
   Phone: Toll Free: 800-223-8720),  Local: 502-491-1900, Customer
   Relations Fax: 502-491-8050, Editorial Department Fax: 502-491-
   4200. Address: _Inside Visual BASIC for Windows_, 9420 Bunsen
   Parkway, Suite 300, Louisville, KY  40220.
   
   (Note: for completeness other VB magazines should be listed, and I
   would like to receive info on those!)
   

6.   WWW pages for VB! [**]
   
   Carl 'n Gary's Visual Basic HomePage is a good place to start:
   
      http://www.apexsc.com/vb/
   
   This page has hotlinks to lots of goodies, including the FAQs,
   clbv.* archives (with search tool), etc. Send any e-mail inquiries
   (about the page!) to:
   
      vb-admin@apexsc.com
   
   [Gary Wisniewski (gary@apexsc.com)]

7.   Are there any examples of commercial applications built using
   Visual Basic?
   
   Profit by Microsoft was written mostly in Visual Basic. In fact,
   Profit was one of three programs selected as PC Magazine's
   Editor's Choice among Windows small business accounting packages.
   Most of the current version of Quicken was written in VB2. The
   viewer/launcher/installer in the oh-so-popular Way Cool [Topic]
   for Windows series of CD-ROMs was written in VB3.
   
   Microsoft uses VB extensively for smaller utilities. 3 of the
   small apps in the Windows and Windows for Workgroups Resource
   Toolkits are written in VB. Also, if you have the Microsoft
   Bookshelf CD-ROM, you will notice that the MVOPTION.EXE program,
   which is an "options" program for MS Viewer, is created in VB.
   
   Note: The existence of VBX files in a package doesn't ecessarily
   mean that it was written in VB. The most popular C++ compilers
   also support VBXes.

8.   Limits of VB?
   
   Are you kidding? VB have *no* limitations... Uh, yeah ;-)
   
   For starters:
   
   * It's not a true compiler, hence it's slow for non-interface
   stuff (it's of
     course slow for interface stuff as well, but that's *Windows*
   not VB)
   
   * It's not really object-oriented (Try looking for the parent of
   ie. a line
     control, and you'll wonder why it has no hWnd  - SpyWorks is an
   add-on you
     may need if this is annoying)
   
   * A statement must be on a single line! (Note: Fixed in VB4!!!!)
   
   * No arrays of constants.
   
   * Your Complaint Here!
   
   An enormous amount of contributers to this topic! Can you guess
   why?
   [Entry suggested by Andre van Meulebrouck (vanmeule@netcom.com)]


C.   COMMON VISUAL BASIC PROGRAMMING QUESTIONS
  

1.   What's the difference between MODAL and MODELESS forms? [++]
   
   MODAL forms are forms which require user input before any other
   actions can be taken place. In other words, a modal form has
   exclusive focus in that application until it is dismissed. When
   showing a modal form, the controls outside this modal form will
   not take user interaction until the form is closed. The internal
   MsgBox and InputBox forms are examples of modal forms. To show a
   form modally, use the syntax:
   
     MyForm.SHOW 1
   
   MODELESS forms are those which are shown but do not require
   immediate user input. MDI child forms are always modeless. To show
   a form modeless, use the syntax:
   
     MyForm.SHOW
   
   (Thanks to John M. Calvert (calvertj@magi.com) for correcting a
   slightly embarrassing mistake in previous versions of this topic)

2.   When/Why should I use Option Explicit?
   
   Option Explicit forces you to declare all variables before using
   them. Opinions vary greatly on this subject. The main reason to
   use the OPTION EXPLICIT statement at the top of all modules is to
   minimize the amount of bugs introduced into your code by
   misspelling a variable name. Most variants of BASIC (including VB)
   have the capability to create variables 'on the fly' (without any
   declarations). This capability can be a double edged sword.
   
   At the minimum, some suggest using the DEFINT A-Z statement in leu
   of OPTION EXPLICIT. This statement will cause any variables which
   are created on the fly to be created as integers as opposed to
   variant (VB 3.0) or single precision (VB 1.0 and 2.0). (Integers
   take up less memory).
   
   The OPTION EXPLICIT statement causes VB to 'disable' its ability
   to create variables on the fly. Thus, all variables must be
   declared using a DIM or REDIM statement. All variables not
   declared will cause an error when the OPTION EXPLICIT statement is
   used. This will eliminate bugs caused by a misspelled variable.
   The option works module-wide, so you can have some modules with
   and some without this option in your project.

3.   Why does everybody say I should save in TEXT not BINARY?
   
   Actually, saving in binary mode is a bit faster, so why do we
   recommend you to save in text?
   
   If you save the source and the project as text, it becomes ASCII
   (or really, ANSI) code that you can edit with any text editor or
   (if you are careful when you save) word processor. If you save in
   binary, only the VB development environment, current or later
   versions, will understand the code. The Setup Wizard can not scan
   binary projects. Also, source documenters and other programming
   tools usually require text mode. If you use text, you can use a
   simple text editor (ie. notepad) to cut and paste code from other
   source/form modules into your current project. Some 'tricks' (like
   making an array of 1 control into a single non-array control
   again) is easily done with an editor but not that easy in the
   environment. If you want to print your project to paper the
   file|print option in the VB environment is often not good enough;
   you may want to import the text files into your word processor.
   And, finally, if something goes wrong (only one byte is changed!)
   you may be out of luck in binary mode. In text mode you will more
   easily be able to fix it.

4.   Is the Variant type slower than using other variable types?
   
   Generally, yes, if we are talking numeric variable types. The
   Variant type also increases memory overhead. To test the speed
   difference, try the following piece of code in something like a
   button_click event and keep the debug window on the screen:
   
     Dim Va As Variant
     Dim In As Integer
     T1! = Timer
     For i% = 1 To 32766
       Va = i%
     Next i%
     T2! = Timer
     Debug.Print "With variant:  "; Format$((T2! - T1!), "0.0000")
     T1! = Timer
     For i% = 1 To 32766
       In = i%
     Next i%
     T2! = Timer
     Debug.Print "With integer:  "; Format$((T2! - T1!),"0.0000")
   
   This test shows (on our test system) that integers are ~60%
   faster! However, for strings there where no real difference, or in
   some instances, variants were faster than strings for routines
   with heavy conversion usage. For the best result in your
   application, test your routines directly.

5.   How do I make a text box not beep but do something else when I
   hit the Enter key?
   
   Put "something else" in your _KeyPress event, depending on what
   you really want. This code example makes *nothing* happen, for an
   extended period of time:
   
     Sub Text1_KeyPress (KeyAscii As Integer)
         If KeyAscii = 13 Then   '13 is Key_Return
            KeyAscii = 0
         End If
     End Sub
   
   This might not be a very nice thing to do, since your users
   usually have some intention when they press Enter. Often they will
   want to jump to the next control, like the Tab key does. To have
   the Enter key emulate the Tab key action, you will need to add the
   line 'SendKeys "{tab}"' above 'KeyAscii=0' in the example above
   (Yes, I thought KeyAscii=9 works but it doesn't! Tab is obviously
   handled by Windows on a lower level).
   
   By the way, you'll also find this in the Microsoft VB Knowledge
   Base (see KB Q78305 and Q85562).
   
   Note: If MultiLine=True you will *not* want to disable the normal
   behaviour of the Enter key.

6.   How do I implement an incremental search in list/dir/combo/file
   boxes?
   
   This is your lucky day. Dan Champagne (Dan_Champagne@dell.com)
   made some VB code (no DLLs are necessary!) which easily provides
   this feature for your applications:
   
     ' Code by Dan Champagne
     ' 4/18/94
     
     ' This code can be used to do an incremental search in either a
     ' list box, dir, combo, or a file box. The following code is set
     ' for a file box called FILE1. To make it work with a list box, or
     ' a file box with a different name, change all occurences of FILE1
     ' with whatever you or VB has named your list, combo, dir, or file box.
     ' There are two places where you will need to change these. They are
     ' on the last couple of lines in the KeyPress code.
     ' Also, thanks to John Tarr for helping debug the code.
     
     'In a .BAS file, add the following:
     'searchme$ is a global vaiable that will keep track of what the
     'user has typed so far.
     Global searchme$
     
     'The following needs to be on one line.
     Declare Function SendMessageBystring& Lib "User" ALIAS
     |"SendMessage" (ByVal hWnd%, ByVal wMsg%, ByVal
     |wParam%, ByVal lParam$)
     
     Global Const WM_USER = &H400
     Global Const LB_SELECTSTRING = (WM_USER + 13)
     Global Const LB_FINDSTRING = (WM_USER + 16)
     
     'In File1 under keydown, add the following:
     'This checks if the user has pressed the up or down arrow.
     'If they have, reset searchme$ to "".
     If KeyCode = 40 Or KeyCode = 38 Then
        searchme$ = ""
     End If
     
     'In File1 under lostfocus, pathchange, patternchange, and click add:
     
     'If the user has done any of the above, reset the searchme$
     'string.
     searchme$ = ""
     
     'In File1 under keypress add:
     
     Dim result&
     
     Select Case KeyAscii
         Case 8     'Backspace
             If searchme$ <> "" Then
                 searchme$ = Left$(searchme$, Len(searchme$) - 1)
             Else
                File1.ListIndex = 0
             End If
             KeyAscii = 0
             Exit Sub
         Case 27    'Escape
             searchme$ = ""
             KeyAscii = 0
             Exit Sub
         Case 13    'Enter
             searchme$ = ""
             KeyAscii = 0
             Exit Sub
         Case Asc("a") To Asc("z"), Asc("A") To Asc("Z"), Asc("'"),
         |Asc("."), Asc(" "), Asc("0") To Asc("9")
             searchme$ = searchme$ & Chr$(KeyAscii)
             KeyAscii = 0
     End Select
     
     result& = SendMessageBystring(FILE1.hWnd, LB_FINDSTRING,
     |0, searchme$)
     
     If result& = -1 Then
        searchme$ = Left$(searchme$, Len(searchme$) - 1)
     Else
        result& = SendMessageBystring(FILE1.hWnd, LB_SELECTSTRING,
        |-1, searchme$)
     End If

7.   How do I get the Tab key to be treated like a normal character?
   
   You must set TabStop = False for ALL controls on the active form.
   Then you will be able to insert "tab" (chr 9) characters in
   controls like the text box.
   
   If you feel you need the Tab key to behave "normal" (ie. jump to
   next control) outside this specific control, it is trivial to
   emulate its functionality in code:
   
     Sub Command1_KeyDown (KeyCode As Integer, Shift As Integer)
       If KeyCode = 9 Then
         If Shift = 0 Then
            Command2.SetFocus 'Tab=Next control
         ElseIf Shift = 1 Then
            Command3.SetFocus 'Shift-Tab=Prev.ctrl.
         End If
       End If
     End Sub
   
   ...etc.

8.   How do I make an animated icon for my program?
   
   For an example on how you change the icon for your application as
   it is displayed when it is minimized, see the example REDTOP in
   the \samples\picclip directory for VB/Win 3 Pro. This demonstrates
   a fancy animated icon.

9.   What is passing by reference?
   
   Arguments are either passed by reference or by value. When they
   are passed by value, they cannot be changed by the procedure or
   function they are passed to. They *can* be altered when passed by
   reference, since passing by reference is just passing the address.
   
   Note that procedures are less strict about variable types when you
   use BYVAL. If you declare that your Sub takes a Variant, VB takes
   that seriously and gives a nasty "mismatch error" if you try to
   pass ie. a string to it. Make it ByVal (at the cost of some speed)
   and your sub will be more tolerant.
   
   Also note the following nasty trap:  Arguments are passed by
   reference unless enclosed by parentheses or declared using the
   ByVal keyword. [VBWin Language Ref., p. 55]

10.  I get a "file not found" error on the IIF function when I
   distribute by program. Uh?
   
   There's a documentation error, since the manual does not tell you
   that the IIF function requires the file MSAFINX.DLL to be
   distributed with your application. No, IIF is not financial (I
   should know, I study finance right now, or at least I should be
   doing that ;-] ).

11.  Is there any way to pass a variable to a form apart from using
   global variables?
   
   The standard workaround is to put an invisible text box (or
   caption or any other control that suits your use.) on the target
   form and access it by Form.textbox = "value". Then you can use the
   Change event of that control to do anything you want in that form.
   Also, check out the .Tag property which is a "what-you-want"
   property where you can hook any string you want onto a control.
   This property can also be accessed from other modules.
   [Dave Mitton (mitton@dave.enet.dec.com)]
   
   Perhaps a more elegant and flexible way is to implement a stack
   with similar routines. I've done this for a math project, but this
   stack was rather complicated and special purpose (and inspired by
   HP calculators, of whihc I'm a great fan).
   
   Jan G.P. Sijm (jan.sijm@intouch.nl) have implemented some routines
   for general stacks:
   
   '-----------------------------------------------------------------
   ---
   Option Explicit                        'Variable declarations
   required
   Dim m_vStack() As Variant              'Stack of variant types
   
   '*-------------
   '*  This function will pop a value of a stack of variant
   '*  values. The value to be popped (e.g. the variable it
   '*  is assigned to) must have one of the basic variable
   '*  types that Visual Basic supports. The type of the
   '*  return value is determined by the type of the variable
   '*  it is assigned to.
   '*
   '*  Input    : None
   '*  Modifies : m_vStack, Stack of variant's
   '*  Return   : Value of last pushed variant
   '*-------------
   Function stkPop () As Variant
     Dim iM As Integer
     iM = UBound(m_vStack)                'Get current stack size
     stkPop = m_vStack(iM)                'Pop value from stack
     iM = iM - 1                          'Decrement number of
   elements
     ReDim Preserve m_vStack(iM) As Variant
   End Function
   
   '*-------------
   '*  This function will push a value onto a stack of
   '*  variant values. The value to be pushed must have one
   '*  of the basic variable types that Visual Basic supports
   '*
   '*  Input    : vValue, Value to be pushed
   '*  Modifies : m_vStack, Stack of variant's
   '*-------------
   Sub stkPush (ByVal vValue As Variant)
     Dim iM As Integer
     On Error Resume Next                 'Trap for undimensioned
   array
     iM = UBound(m_vStack)                'Get current array size
     iM = iM + 1                          'Increment number of
   elements
     ReDim Preserve m_vStack(iM) As Variant
     m_vStack(iM) = vValue                'Push value on stack
   End Sub
   
   'This is a short example of how the stack routines can be used in
   a
   'Visual Basic program. This example will push three parameters
   onto
   'the stack. A modal dialog is displayed. The dialog will pop the
   'parameters from the stack and set edit controls with the values.
   
   Sub ShowDialog()
     '
     '  Push the parameters for the dialog
     '  onto the stack and display the dialog
     '
     stkPush sName
     stkPush sStreet
     stkPush sCity
     dlgPerson.Show MODAL
   End Sub
   
   Form_Load()
     '
     ' Pop the parameters of this dialog from the
     ' stack in REVERSED ORDER and place the values
     ' in the appropriate edit controls.
     '
     dfCity.Text = stkPop()
     dfStreet.Text = stkPop()
     dfName.Text = stkPop()
   End Sub
   '-----------------------------------------------------------------
   ---

12.  How should dates be implemented so they work with other language
   and country formats?
   
   If you use ie. MM/DD/YY format dates in a program, you will get
   either a runtime-error (ie. month>12) or the wrong date (ie. March
   12 instead of December 3) when your program is used in Europe. And
   vice versa, of course. Even Microsoft's own example programs (like
   the MAPI sample) make this stupid mistake and fail miserably. Use
   the Format command to make sure you get the date you want. For
   example:
   
     strTodaysDate = Format[$](Now, "Short Date")
   
   As a side note, Microsoft has taken much heat on the newsgroup for
   VB's bad support for internationalization! Just try to make a date
   literal in source code that works everywhere as a little exercise.
   Answer elsewhere in this document. No prizes  :-)

13.  Can a VB application be an OLE server?
   
   No. You'll have to use an external DLL/VBX. If you see any
   examples, please tell the newsgroup.

14.  How do I dial a phone number without using the MSCOMM VBX?
   
   The MSCOMM VBX that comes with VB/Pro is great for creating
   communication programs, but it's overkill for dialing a phone
   number. Try the following code:
   
     PhoneNumber$ = "(123)456-7890"
     Open "COM2:" For Output As #1   'or COM1
     Print #1, "ATDT" & PhoneNumber$ & Chr$(13)
     Close #1
   
   Ian Storrs <exuian@exu.ericsson.se> informed me that he had
   experienced problems with this when the VB program was run from a
   network drive. A file named "COM1" was created on the disk! Jeff
   Rife <jrife@health.org> put in the ":" after COM2 to solve that
   problem!
   
   This trick is probably not a good idea for bigger applications,
   but it's nice for small personal utilities.

15.  I have [several] megabytes of memory. Why do I get an "out of
   memory" error? [++]
   
   This problem and its solution(s) should not be applicable to
   Windows 95.
   
   Unfortunately, Microsoft has been more famous for memory barriers
   than anything else. This is a late descendant of the infamous 640K
   barrier that has been plaguing us for years. Although Windows
   allows the user to access several megabytes of memory, it uses two
   limited (64K) memory areas called User Heap and GDI Heap for some
   specific data structures. Go to the Help|About box in Program
   Manager to see the percentage of free resources in the *most*
   exhausted heap. If these areas are exhausted, you are out of luck.
   VB programs are unfortunately rather greedy on these structures.
   Windows 4 is supposed to free us from this limitation...
   
   Note that every visible control (ie every button) is a window to
   Windows. Every new control takes up some bytes in the precious
   User heap.
   
   Also, there is another way to run out of memory in Windows, not
   related to VB. Windows requires free Upper Memory Area (UMA, also
   called Upper Memory Blocks, not to be confused with High RAM,
   which is the first 64K of extended memory) to do certain tasks. If
   you use QEMM or DOS 6+ MemMaker and you have many device drivers
   (network, etc) this area may have been filled up before you launch
   Windows. You will then be unable to start applications, even
   though you have plenty of free RAM. The problem can be solved with
   careful memory setup, but this is far beyond the scope of this
   FAQ.
   
   On a completely unrelated problem: When you run a program with an
   outline control with some ATI graphics cards, it may crash with
   just that error message. (see Knowledge Base Q100194 PRB: "Some
   ATI Video Drivers Hang When Using MSOUTLIN.VBX")

16.  How do I mimic a toggle button? [++]
   
   The only "fix" we know for this problem is to use a picture or
   image control to mimic the action of a button or button3d control.
   You need two bitmaps, one for buttonup and one for buttondown (and
   perhaps one more for inactive state). This is a kluge, we know.
   Look at the button bar used in the MDINOTE sample program supplied
   with VB for an example of this.

17.  How do I get my application on top?
   
   To force a form to the front of the screen, do the following
   command:
   
     Form1.ZOrder
   
   To make the application *stay* on top, put the Zorder command in a
   Timer event repeatedly called, say, every 1000 msecs. This makes a
   "softer" on-top than other methods, and allows the user to make a
   short peek below the form.
   
   There are two different "Zorder"'s of forms in Windows, both
   implemented internally as linked lists. One is for "normal"
   windows, the other for real "topmost" windows (like the Clock
   application which is distributed with MS Windows). The Zorder
   command above simply moves your window to the top of the "normal"
   window stack. To make your window truly topmost, use the
   SetWindowPos API call like this:
   
     'Make these declares:
     Declare Function SetWindowPos Lib "user" (ByVal h%,
     |ByVal hb%, ByVal x%, ByVal y%, ByVal cx%, ByVal cy%,
     |ByVal f%) As Integer
     Global Const SWP_NOMOVE = 2
     Global Const SWP_NOSIZE = 1
     Global Const FLAGS = SWP_NOMOVE Or SWP_NOSIZE
     Global Const HWND_TOPMOST = -1
     Global Const HWND_NOTOPMOST = -2
     
     'To set Form1 as a TopMost form, do the following:
     res% = SetWindowPos (Form1.hWnd, HWND_TOPMOST, 0, 0,
     |0, 0, FLAGS)
     'if res%=0, there is an error
     
     'To turn off topmost (make the form act normal again):
     res% = SetWindowPos (Form1.hWnd, HWND_NOTOPMOST, 0, 0,
     |0, 0, FLAGS)

18.  Is there a way to break long lines in VB code?
   
   There is unfortunately no line continuation character in VB/Win
   3.0. Excel 5 VBA does, however, use Space+Underscore (" _") as a
   line continuation character, and we hope this will be included in
   the next version of VB.
   
   There are a few tricks you can use to reduce line length, but
   unfortunately there is very little to do with DECLARE statements
   which can get very long.
   
   Print your source in landscape   :-/

19.  How do I remove/change the picture property of a control at
   design time?
   
   Mark the (bitmap) or (icon) text in the property window and press
   Del or Backspace. "No!" I hear you cry, "It doesn't work". Well,
   it does if you first select the object from the combo box at the
   top of the Properties Window, and then immediately afterwards
   doubleclick (or paint over) the "(bitmap)" text and press Del.
   Alternatively, just click on another control, then click back to
   the first control. Now Del works. Who said "bug"?
   
   If you want to paste your picture directly into the VB program by
   pressing Ctrl-V when you are editing the picture property, you
   will have to use a semilar procedure: select the control, select
   the property, press Ctrl-V. If you try it again without
   deselecting the control first (or selecting it from the combo
   box), it doesn't work.

20.  Is a [foo] VBX/DLL available as shareware/freeware?
   
   Part 4 of the FAQ is Adam Harris' excellent "Shareware Custom
   Controls List". Please consult this list before you post this
   question.
   
   The following type of controls are NOT known to be available as
   sw/pd/fw for Visual Basic, only as commercial toolboxes (If you
   feel like making any of these for VB and sharing it for a modest
   fee, you will become very popular!):
   
   a.   ZModem communication control/source
   
   b.   Rich Text Format-control or other mixed font/word processor
      control (rumours indicate that this will be in the Windows 4 API, and
      therefor available from VB)
   
   c.   Matrix math
   
   If any of these should be available, please tell us.

21.  How do I make my applications screen-resolution independent?
   
   There are two methods: Either get a custom control that does the
   job for you, or you write lots of complicated code in the Load and
   Resize events.
   
   For the first option, check out VideoSoft's $hareware VSVBX.VBX
   (download VSVBX.ZIP from Cica or mirrors). It has a will of its
   own, as you will experience, but it's generally better than trying
   what is described below.
   
   For the brave (or stupid), try to write "screen resolution-smart
   code" in the form's Load event. If the form is resizable (normally
   it should be), you'll have to put some magic into the Resize event
   as well. There are 4 rules of thumb:
   
   a.   Do not trust the form's height and width properties.  These
      measure the entire form, not the client area where your controls are.
      To see this in action, create a simple applet with the only code being
      in the resize event which resets a line control from 0,0 to the form's
      width,height properties.  The top left corner is in the client area,
      the bottom right corner disappears.  The API call GetClientRect will
      return the size of the client area in pixels.  You can use the screen
      object's TwipsPerPixelX and TwipsPerPixelY properties to convert from
      pixels to twips. If that's not enough, GetWindowRect will return the
      actual size of the entire form, client and non-client areas combined.
      GetSystemMetrics will return individual pieces of things like border
      width/hight, caption height, etc.
   
   b.   Use the TextWidth and TextHeight properties.  You can use them
      off the form if all your controls share the same font, otherwise use
      them off of the given control.  I typically do a TextWidth("X") and
      TextHeight("X") to get a value which I use as a margin between
      controls.  I grab these values on startup, and multiply it by 2, 1.5,
      .75, .5, .25 to get varying margin sizes, depending on how close or
      far apart I want to space things. If your control has an autosize
      property, you may want to use it, and then calculate the maximum width
      of a control in a given "column" of controls on your screen and
      position all of them accordingly.
   
   c.   Try not to resize your controls in the resize event.  You will
      spawn another resize event in the process.  Of course, you can use a
      flag to determine whether the resize event is the original event or
      the spawned one.  Using the load event, and setting the forms borders
      to fixed minimizes the amount of work you have to do.
   
   d.   Make sure you use a consistant scale.  I don't even bother with
      the scale properties, but instead just convert pixels (from API calls)
      into twips and be done with it.  If you do use scale properties, be
      sure you convert your numbers correctly.  I had no end of difficulty
      when I failed to convert into twips with one number that was used in a
      series of calculations to position controls.  Also be sure all your
      controls share the same SCALE -- another nasty problem I had before I
      gave up on them completely.
      [Thanks to our generous anonymous source "D"]

22.  How do I do Peek and Poke and other low-level stuff? [++]
   
   VB provides no mechanism for this.  There are several 3rd party
   pkgs. which provide this.  Also, this often comes up in regards to
   the comm ports and you can many times do what you want with the
   mscomm.vbx.
   [George Tatge (gat@csn.org)]
   
   On The Developer Network Library CD, you'll find the following:
   
   VBASM is a Microsoft(R) Visual Basic(R) dynamic-link library (DLL)
   that
   helps Visual Basic programmers accomplish tasks that are difficult
   or
   impossible using Visual Basic alone. This sample application
   includes
   two programs, SNOOPER and TXTALIGN, that demonstrate the DLL's
   use.
   The DLL contains many low-level routines such as access to real
   and
   protected mode interrupts, port input/output (I/O), peek/poke,
   control
   manipulation, and so on. These routines and their associated
   functions
   include:
   
   * Control Manipulation
   vbGetCtrlHwnd, vbGetCtrlModel, vbGetCtrlName, vbRecreateCtrl
   
   * Pointer and Memory
   vbGetData, vbGetLongPtr, vbPeek, vbPeekw, vbPoke, vbPokew, vbSAdd,
   vbSetData, vbSSeg, vbVarPtr, vbVarSeg
   
   * Byte/Word/Long Manipulation
   vbHiByte, vbHiWord, vbLoByte, vbLoWord, vbMakeLong, vbMakeWord
   
   * I/O Access
   vbInp, vbInpw, vbOut, vbOutw
   
   * Interrupts
   vbInterrupt, vbInterruptX, vbRealModeIntX
   
   * Others
   vbGetDriveType, vbShiftLeft, vbShiftRight
   [Deane Gardner <deaneg@ix.netcom.com> quotes Microsoft]
   
   There's a shareware package for in/out routines, btw.

23.  Why doesn't "my string" & Chr$(13) do what I want?
   
   You need to also add a Chr$(10):  "my string" & Chr$(13) &
   Chr$(10) will give you a CR and LF.
   [George Tatge (gat@csn.org)]

24.  How do I prevent multiple instances of my program?
   
   In VB 3, the property App.PrevInstance is set to True if an older
   instance of the program already exist.
   
   The following piece of code, stolen from MS KB article Q102480,
   will activate the old instance and then terminate itself:
   
     Sub Form_Load ()
       If App.PrevInstance Then
          SaveTitle$ = App.Title
          App.Title = "... duplicate instance."      'Pretty, eh?
          Form1.Caption = "... duplicate instance."
          AppActivate SaveTitle$
          SendKeys "% R", True
          End
       End If
     End Sub
   
   As Robert Knienider(rknienid@email.tuwien.ac.at) informed me, this
   piece of code WILL NOT work for non-English versions of MS Windows
   where the word for "Restore" does not have "R" as the underlined
   word. Replace the "R" in the SendKeys line above with "{ENTER}" or
   "~".
   
   Note that you shouldn't prevent multiple instances of your
   application unless you have a good reason to do so, since this is
   a very useful feature in MS Windows. Windows will only load the
   code and dynamic link code *once*, so it (normally) uses much less
   memory for the later instances than the first.

25.  How do I implement an accelerator key for a text box?
   
   You want to use a label caption to identify a text box and to act
   as if it were the text box caption:
   
   Example:
   
   &Label1  [text1      ]
   
   How should I do to set the focus to text1, by typing <ALT>L
   
   Make sure that the TabIndex property for the text box is 1 greater
   than the
   label's TabIndex. Since a label can't have the focus, the focus
   will go to the next item in the tab order, which would be the text
   box.
   
   Here's any easy way to set the TabIndex for a busy form. Select
   the object that should be last in the tab order and then select
   the TabIndex property. Press 0 (zero), click on the next to last
   object, press 0, click on the  the next object back, press 0, etc.
   When you're done, all of the TabIndexes  will be in order, because
   VB increments all of the higher TabIndexes when you put in a lower
   number.
   
   Many thanks to Jonathan Kinnick and Gary Weinfurther that provided
   the answer
   on the FIDO net echo VISUAL_BASIC.
   [Tiago Leal (Tiago.Leal@p25.f1.n283.z2.gds.nl)]

26.  How do I force a file dialogue box to reread the currect disk?
   
   If you make a simple dialogue box modelled after common dialogue
   (normally you should *use* the common dialogue VBX!), you will
   notice that reselecting the diskette drive will not really rescan
   the disk. Very annoying to change to C:, and to reselect A: just
   to make it read the directory of a new diskette.
   
   To solve this problem, put
   
     drive1.refresh
     dir1.refresh
     file1.refresh
   
   in the code for the "Rescan" button (or whatever).

27.  How do I get the number of free bytes on a disk? [++]
   
   As far as I know, there is three possibilities:
   1. SETUPKIT.DLL as mentioned above
   2. Arjen Broeze's VBIO.VBX or something like that, with a lot of
   options.
   3. Make your own DISKINFO.DLL from the example code in VBKB
   article Q106553.
   
   See Article Q113590 (or Q106553) in Microsoft's VB KnowledgeBase.
   A short extract follows:
   
   Declare Function DiskSpaceFree Lib "SETUPKIT.DLL" () As Long
   
   Dim free_space& ' Holds number of bytes returned from
   DiskSpaceFree().
   ChDrive "c:"    ' Change to the drive you want to test.
   free_space& = DiskSpaceFree()
   [Geir Tutturen(itfgt@nlh10.nlh.no)]

28.  Data Control missing from toolbox when I use VB under NT 3.5.
   Huh?
   
   Open the VB.INI file and add these lines under the [Visual Basic]
   heading:
   
   ReportDesign=1
   DataAccess=1
   [Danny Ames (dames@pic.net)]


D.   ADVANCED VISUAL BASIC PROGRAMMING ISSUES
  

1.   How do I tell when an application executed using the SHELL
   command is finished?
   
   Shell() doesn't really return a task handle, it returns an
   instance handle. Any documentation that says otherwise is wrong.
   But never mind that; the answer to your question is to use the API
   call GetModuleUsage.
   
     'Put this in the general declarations of your form/module
     Declare Function GetModuleUsage Lib "Kernel" (ByVal
     |hModule As Integer) As Integer
     
     'Here's where you shell out to the other program
     intHandle = Shell("PROGRAM.EXE")
     Do While GetModuleUsage(intHandle) > 0
        DoEvents
     Loop
   [Kenn Nesbitt, Microsoft Consulting Services (kennn@netcom.com)]
   
   The FindWindow command can also be used (search the Tips help file
   for "How VB Can Determine if a Specific Windows Program Is
   Running"). I have had to use this when the program I shelled to
   unloaded itself and ran a different EXE. My program thought the
   shell was done (since the shelled EXE ended), but it really had
   just "moved on" to another EXE. Generally, the code in cases like
   this must be customized to fit the situation.
   [John McGuire (jmcguire@jax.jaxnet.com)]

2.   How do I access C style strings?
   
   Use the 'lstrlen' and 'lstrcpy' calls found in the Kernel DLL.

3.   How can I change the printer Windows uses in code without using
   the print common dialog? How can I change orientation?
   
   You can change the printer the VB 3.0 Printer object is pointing
   to programmatically (without using the common dialogs). Just use
   the WriteProfileString API call and rewrite the [WINDOWS],  DEVICE
   entry in the WIN.INI file!  VB will instantly use the new printer,
   when the next Printer.Print command is issued. If you get the old
   printer string before you rewrite it (GetProfileString API call),
   you can set it back after using a specific printer. This technique
   is especially useful, when you want to use a FAX printer driver:
   Select the FAX driver, send your fax by printing to it and switch
   back to the normal default printer.
   [Hajo Schmidt (hajo@bwl.bwl.th-darmstadt.de)]
   
   It is recommended (and polite, as we're multitasking) to send a
   WM_WININCHANGE (&H1A) to all windows to tell them of the change.
   Also, under some circumstances the printer object won't notice
   that you have changed the default printer unless you do this.
   
     Declare Function SendMessage(ByVal hWnd As Integer,
     |ByVal wMsg As Integer, ByVal wParam As Integer,
     |lParam As Any) As Long
     Global Const WM_WININICHANGE = &H1A
     Global Const HWND_BROADCAST = &HFFFF
     ' Dummy means send to all top windows.
     
     ' Send name of changed section as lParam.
     lRes = SendMessage(HWND_BROADCAST, WM_WININICHANGE, 0,
     |ByVal "Windows")
   [Nic Gibson (nic@skin.demon.co.uk)]
   
   To change between landscape and portrait orientation, search of
   VBKB_FT on "lands*" finds Article ID: Q80185 "How to Set Landscape
   or Portrait for Printer from VB App".
   
   This is an extract:
   
   Declare Function Escape% Lib "GDI" (ByVal hDC%, ByVal nEsc%, ByVal
   nLen%,
     |lpData As Any, lpOut As Any)
   
   Sub Command1_Click ()
      Const PORTRAIT = 1
      Const LANDSCAPE = 2
      Const GETSETPAPERORIENT = 30
      Dim Orient As OrientStructure
      Printer.Print ""
      Orient.Orientation = LANDSCAPE
      x% = Escape(Printer.hDC, GETSETPAPERORIENT, Len(Orient), "",
   Null)
      Print x%
   End Sub
   [Ayn Shipley (ashipley@hookup.net)]

4.   Any tips for speeding up VB?
   
   Who said "code in C"???? ;-)
   
   a.   When SHOWing a form with lots of bound controls, have a blank
      frame covering everything. Then, in the Form_Activate event, set the
      Frame.Visible = False. This greatly speeds the display of the form and
      hides ugly thrashing as the data controls initialize.
      [Christopher Biow (biow@cs.umd.edu)]
   
   b.   Try to keep any Global definitions to a minimum.  Massive numbers
      of global variables really seem to slow VB Windows down (besides
      chewing up memory).  In other words, if you've pasted a lot of stuff
      from the globals.txt file, trim all definitions and variables you
      don't use in your application.
   
   c.   Keep the total number of controls and forms used to a minimum
      (you've probably already guessed that).
   
   d.   Keep fancy graphics to a minimum (another one you know).
   
   e.   Try "pre-processing" in the background (using Do_Events).
      Doesn't really speed anything up, but often there is a lot of "idle"
      time while the user is selecting menu's, buttons and such - if you can
      do some calculations, image loading or whatever during this idle time
      your user perceives the application is faster than it really is.
   
   f.   Hide often-used forms rather than unloading them. Unloading saves
      memory, but it takes longer to re-load a form than to simply "un-hide"
      it.
      [Tips b to f by Galen Raben (galenr@gr.hp.com)]
   
   The following tip is along the same lines, but with a code sample.
   They are provided by Andy Dingley (dingbat@codesmth.demon.co.uk):
   
   You're limited by the system as to how quickly you can go from
   calling frmMyForm.Show to being able to type into the controls,
   but you can make the form *appear* to display faster. One
   technique is to keep forms loaded, and just switch their
   visibility on and off. This is heavy on resource usage, and
   doesn't help for the first time they're shown.
   
   Most forms have some processing (eg. querying a table to fill a
   list box) that goes on when they're first opened, and this is what
   causes the most serious delay. It's possible to display the form,
   make its controls appear on screen, then do the slow processing
   before finally making the form "live". As the user can see things
   happening, the perceived delay is less obvious.
   
   Include the following code in your form:
   
     Option Explicit
     Dim FirstActivation as integer
     
     Sub Form_Activate
        DoEvents   'Allow the _Load event to be seen on screen
        If FirstActivation Then
     
           ' Do all the slow loading stuff here
           If FillComboBox <> 0 Then
              Unload Me 'If it all goes horribly wrong, then you
                        'can call Unload from an _Activate event
                        '(Which you can't do from the _Load event)
           End If
           FirstActivation = False
        End If
        Screen.MousePointer = DEFAULT
     End Sub
     
     Sub Form_Load
        FirstActivation = True
     End Sub
     
   Show the form by using:
     
     Screen.MousePointer = HOURGLASS
     frmMyForm.Show MODAL
     
   
   Bruce Garrett (bruceg@access2.digex.net) had the following tips
   from his VBITS 93 notes:
   
   - Polling a control for its properties directly is 10 to 20
     times slower then placing the property values you need into
     variables and testing the value of the variables.
   
   - Swap tuning: Modules are not loaded until used; put related
     code in the same modules, reduce the number of intermodule
     calls and keep modules small.
   
   - Binary file I/O is faster then Text/Random.
   
   There was also a lot of discussion about "apparent" speed i.e: how
   it looks on the screen as opposed to how fast it's chugging
   internally. It was noted that the cute little flashing menu items
   and exploding windows in the Mac amounted to a little razzle-
   dazzle to distract you from how long it took to actually load
   something and get it on the screen.  Keeping all your forms loaded
   but hidden until needed was suggested.  Also the use of progress
   indicators and a simple quickly loaded and drawn startup form.
   Also preloading data you expect to need.

5.   How do I speed up control property access?
   
   Instead of using a property in a loop, you will be better off
   using a normal variable in the loop and then assign the variable
   once to the property afterwards. Also, when reading a property,
   you should read it once into a variable instead of using it in a
   loop.
   
   Sometimes it is not possible to simply put contents of a property
   into a variable. For example, if you are using a list box or you
   need to conserve memory. In these cases you can send the
   WM_SetRedraw message to the control to prevent redrawing. You can
   typically increase the speed 6-10 times - or even more.
   
     'Add the following declares:
     Declare Function SendMessage Lib "User" (ByVal hWnd As
     |Integer, ByVal wMsg As Integer, ByVal wParam As
     |Integer, lParam As Any) As Long
     Const WM_SetRedraw = &HB
     
     'Add this to your code:
     Result% = SendMessage(Text1.hWnd, WM_SetRedraw, 0, 0)
     'redraw off
     'Do your stuff here!
     Result% = SendMessage(Text1.hWnd, WM_SetRedraw, 1, 0)
     'redraw on
   
   This same method applies to list boxes and other controls.

6.   How much gain in performance will I get if I write my number
   crunching routines in C instead of Visual Basic?
   
   Probably the best solution to the number crunching problem is to
   write the number crunching routines as a custom control or a DLL,
   and plug it into a VB app. VB interface handling is not
   significantly slower than, say C++, and most of the wait is
   associated with Windows.
   
   Some real world experience speaks volumes about this one:
   
   I wrote some time consuming code in VB to solve a combinatorical
   (does this word exist in English?) problem. The code consists of
   one main recursive function, which calls itself very often. It
   took a night to compute a certain problem. I was rather
   disappointed and then decided to write the central routine in C++.
   It was a 1:1 transcription. The routine was compiled with the MS
   C++-Compiler. It took only 22 Minutes for the same problem.
   Amazing, isn't it? The routine doesn't do any floating point
   arithmetic, only integer, and handles some arrays. The PC was a
   33MHz 486. And the second amazing thing is, that a IBM RS6000
   (560)-Risc-machine needed 17 Min for the same code. I was the only
   one on the machine. I thought it should be much faster. The MS C++
   seems to make very fast, optimized code. The optimization was
   configured to make fast code.
   [Christoph Steinbeck (steinbeck@uni-bonn.de)]

7.   How do you make a TEXTBOX read only? Or, how do I prevent the
   user from changing the text in a TEXTBOX?
   
   There's a lot of ideas on this one. You can grab the _KeyPress and
   _KeyDown events and set them to zero. However, the best idea is to
   use the Windows API SendMessage function to tell the control to
   become read-only:
   
     'After making the following declarations...
     Global Const WM_USER = &H400
     Global Const EM_SETREADONLY = (WM_USER + 31)
     Declare Function SendMessage Lib "User" (ByVal hWnd As
     |Integer ByVal wMsg As Integer, ByVal wParam As
     |Integer, lParam As Any) As Long
     
     'Then Try:
     SendMessage(Text1.hWnd, EM_SETREADONLY, 1, 0)
     [Pete Jones (pjones@csi.compuserve.com)]
   
   This will still allow the user to copy *from* the text box. If you
   need to disable this (why?), steal the Ctrl-C in the _KeyPress
   event.

8.   How can I create a VBX?
   
   VBXs (Visual Basic eXtensions) are practically always written is C
   (Borland C++, but mainly MS VC++). You should refer to the
   _Control Development Guide_ (in VB Professional Features Vol. I)
   and any relevant documentation for your compiler. Followup
   questions should normally be directed to comp.os.ms-
   windows.programmer.* or comp.lang.c*.
   
   There are some example VBX's with C code supplied with VB3 Pro.
   You'll find them under the directory [VB]\CDK.

9.   How do you change the system menu (on the Control-Menu Box)?
   
   You can turn off the minimize and maximize menu options by
   changing properties, but what if you need to remove the "close"
   option?
   
     'Make the following declares.
     Declare Function GetSystemMenu Lib "User" (ByVal hWnd
     |As Integer, ByVal bRevert As Integer) As Integer
     Declare Function RemoveMenu Lib "User" (ByVal hMenu
     |As Integer, ByVal nPosition As Integer, ByVal wFlags As
     |Integer) As Integer
     Global Const MF_BYPOSITION=&H400
     
     'Use the following code to remove the "close" option.
     SystemMenu% = GetSystemMenu (hWnd, 0)
     Res% = RemoveMenu(SystemMenu%,6, MF_BYPOSITION)
     '(also remove the separator line)
     Res% = RemoveMenu(SystemMenu%,6, MF_BYPOSITION)
   
   Adding menu items to the control menu is more complicated, since
   you need to respond to the events triggered when the user selects
   the new options. The newest Message Blaster (msgblast.vbx, see
   details in beginning of FAQ about how to get files) contains
   example code.

10.  How do I play MID, WAV or other multimedia files?
   
   Use the MSMCI.VBX, provided with VB/Win Pro 3.0. You can also
   declare and call the MM-functions manually:
   
     Declare Function mciExecute Lib "MMSystem"
     |(ByVal FileName as String) As Integer
     
     Sub Form1_Click ()
         iResult = mciExecute("Play c:\windows\mkmyday.wav")
     End Sub
   
   Also:
   
   Playing a WAV file is covered in the VB Tips help file (there is a
   Windows call that is for this specificially; see below). The
   routine won't play MIDI files or other sound formats, however.
   
   Declare Function sndPlaySound Lib "MMSYSTEM.DLL"
    |(ByVal WavFile$, ByVal Flags%) As Integer
   Global Const SND_SYNC = &H0
   Global Const SND_ASYNC = &H1
   Global Const SND_NODEFAULT = &H2
   Global Const SND_LOOP = &H8
   Global Const SND_NOSTOP = &H10
   Global Const SND_USUAL = SND_ASYNC And SND_NODEFAULT
   [John McGuire (jmcguire@jax.jaxnet.com)]

11.  How can I call a 'hidden' DOS program from VB?
   
   If you run a DOS program minimized using the SHELL command, it
   will never complete. This is because DOS tasks by default are NOT
   setup to run in the background. The easiest way to get around this
   is to make a PIF file for the program you need to run with the
   "Background" option checked. Then SHELL to the PIF file to run the
   DOS program and it will return control to your VB application when
   it terminates.
   
   Tip: If you edit or replace the _DEFAULT.PIF file in the Windows
   directory to allow execution in background, this will apply to all
   DOS boxes that is not run with it's own .pif!

12.  How do I do drag & drop between applications?
   
   MSGBLAST.ZIP (the famous Message Blaster by Ed Staffin and Kyle
   Marsh) available on Cica and mirrors tell you *everything* you
   want to know about this and other advanced stuff. This is now
   (inexpensive) shareware, but the older freeware version is still
   supposed to be available. Get the file mentined above for more
   info.
   
   Short glossary for the confused ones  :-)
   Drag & Drop Client: the form you drop objects to/on
   Drag & Drop Server: the form you drag object(s) from

13.  How do I use GetPrivateProfileString to read from INI files?
   
   There's a good example of accessing *.INI files in the Knowledge
   Base, but here's the basic idea:
   
     'You declare these API function as usual:
     Declare Function GetPrivateProfileString Lib "Kernel"
     |(ByVal lpApplicationName As String, ByVal lpKeyName
     |As Any, ByVal lpDefault As String, ByVal
     |lpReturnedString As String, ByVal nSize As Integer,
     |ByVal lpFileName As String) As Integer
     
     'Then in your code you do like below:
     strIniFile = "WIN.INI"
     strSection = "MyProgram"
     strKey = "Language"
     strDefault = "English"
     iLength = 70
     strReturn = String$(iLength, " ")  'Pad the string first!
     iResult = GetPrivateProfileString(strSection, strKey,
     |strDefault, strReturn, iLength, strIniFile)
   
   WARNING: Be aware that there was an ERROR in the Windows 3.1 API
   documentation that came with VB. Here's the scoop:
   
   Knowledge Base article Q110826 (DOCERR: GetPrivateProfileString
   Declaration Incorrect in API) corrects a documentation error for
   the GetPrivateProfileString function call as described in the
   Windows version 3.1 API Reference help file that shipped with
   Microsoft Visual Basic version 3.0 for Windows. The CORRECT
   declaration is as follows:
   
     Declare Function GetPrivateProfileString Lib "Kernel"
     |(ByVal lpApplicationName As String, ByVal lpKeyName
     |As Any, ByVal lpDefault As String, ByVal
     |lpReturnedString As String, ByVal nSize As Integer,
     |ByVal lpFileName As String) As Integer
   
   Note that the "ByVal" keyword was omitted from the second
   parameter in the online reference. This means that the function is
   passing the second parameter (lpKeyName) by reference. It needs to
   be passed by value.
   
   The most common problem that occurs when using the incorrect
   declaration is that when the function is called, it returns a copy
   of "lpdefault" in the "lpReturnedString" parameter instead of the
   actual value referenced by KeyName.
   
   OOPS: As P. Wierenga (pwiereng@sol.UVic.CA) told me, the same doc
   error applies to Writeblablabla:
   
   DOCERR: WriteProfileString Declaration Incorrect in API Article
   ID: Q115328
   
   The correct declaration is as follows:
   
   Declare Function WritePrivateProfileString Lib "Kernel"
                                    (ByVal lpApplicationName As
   String,
                                     ByVal lpKeyName As Any,
                                     ByVal lpString As Any,
                                     ByVal lplFileName As String) As
   Integer
   
   (all on one line of course!)
   

14.  How do I implement Undo?
   
   For most controls, you will have to keep track of changes
   yourself. There's no magic involved, just some coding. However, if
   you use the standard Text box or Combo box, Windows provides a
   "free" undo function for you!
     
     'Do the following declares:
     Declare Function SendMessage Lib "User" (ByVal hWnd As
     |Integer, ByVal wMsg As Integer, ByVal wParam As
     |Integer, lParam As Any) As Long
     Global Const WM_USER = &h400
     Global Const EM_UNDO = WM_USER + 23
     
     'And in your Undo Sub do the following:
     UndoResult = SendMessage(myControl.hWnd, EM_UNDO, 0, 0)
     'UndoResult = -1 indicates an error.

15.  How do I create a window with a small title bar as in a floating
   toolbar?
   
   Download the MSGBLAST VBX from ftp.microsoft.com (filename
   msgblast.zip) or (better) from ftp.cica.indiana.edu or mirrors.
   The example files provide an example of a form with a small title.
   When you see it, you'll understand why I haven't include a full
   explanation here!

16.  What is Pseudocode?
   
   VB/Win does not generate machine code like most compilers do.
   Instead it creates what is called pseudocode (a real misnomer,
   IMO). A good explanation is given below:
   
   A bit of history: the original P-code was an instruction set for a
   "virtual Pascal" machine. This came with a portable Pascal
   compiler written at ETH in Zuerich. The portable compiler produced
   instructions for this phony machine which had an instruction set
   ideally suited to the stack and heap management of Pascal.  To
   executed portable Pascal programs, you had two choices: either
   write an interpreter for P-code, or translate the small set of P-
   code instructions (there were about 80) into assembler; assemble
   it; and run it at native speed.  Thus "P-code" originally stood
   for "Portable" or "Pascal" code. The broader meaning, "pseudo-
   code" came later. P-code was widely popularized by the UCSD Pascal
   system, a small workstation that was implemented entirely in Pcode
   and interpreted. It was sold for some years, and one company even
   re-did the microcode for a PDP-11 microchip to interpret P-code.
   The original Borland Turbo Pascal had obvious similarities to the
   UCSD system although it was not interpreted. The dialect was
   virtually identical.  Today P-code is used extensively in
   Microsoft apps, for two reasons. First, it is much more compact
   than  native code; so the apps are smaller. Second, having an
   interpreter at the core of an app makes it much easier to
   customize and extend. That is why VB is becoming the heart of the
   MS major apps.  It is simply not true that P-code apps run much
   slower than native apps. The slowdown is determined by the
   granularity of the interpreted routines. If every little thing is
   an interpreted op, the slowdown might be as much as 3-to-1 for the
   80x86 architecture, or about 2-to-1 for the Motorola 68000 family
   (which is better suited to writing interpreters).  But in
   practice, modern P-code systems have large-scale instructions,
   each of which is executed by a big compiled subroutine. These subs
   run at native speed, so the overhead of the interpreter is
   occasional at worst.
   [Roger E. Ison (r_ison@csn.org)]
   
   It is also possible that since the code may not need recompilation
   to run on other platforms *if* the run-time interpreter is first
   ported, VB applications can become very portable. This depends on
   Microsoft's long-term plans.
   
   A note on the word "pseudocode": I wrote above that it is a
   misnomer, and I stand on that. Pseudocode is *really* the pascal-
   like (mostly) explanation of an algorithm that is intended for
   human readers, not computers. But since somehow the term
   pseudocode stuck to the psaudo-machine-code created by VB the word
   is used here.

17.  Does VB support pointers to functions?
   
   No, it does not.
   [George Tatge (gat@csn.org)]

18.  How do I program the Novell NetWare API from VB?
   
   Tom Tregilgas (Tom.Tregilgas@InfoB.unisg.ch) had a lot of
   information on this one. Normally I leave it to the other FAQ
   parts to list books & how-to-get-info's, but since this topic is
   very specific and more NetWare than VB I include all the stuff
   here for your convenience:
   
   If you are interested in seeing how Visual Basic can be used for
   NetWare programming, obtain the following files from your friendly
   neighboorhood Novell FTP Mirror site.
   
   Mirror sites are (according to ftp.novell.com):
   
         Novell Germany            ftp.novell.de
         Netherlands               ftp.rug.nl
         United Kingdom            ftp.salford.ac.uk
         Logan, Utah               netlab2.usu.edu
         New Zealand               tui.lincoln.ac.nz
         Tuscaloosa, Alabama       risc.ua.edu
         Ottowa, Ontario, CA       novell.nrc.ca
         Boston, Mass              bnug.proteon.com
   
   novlib\11\nivb.zip              Netware Interface for Visual Basic
   novlib\11\nwtest.zip            NetWare Test for Visual Basic
   
   There are also two Novell App Notes on the subject of using
   NetWare with Visual Basic (although this is _NOT_ supported by
   Novell...) which are:
   
   October 92      Interfacing Visual Basic for Windows and NetWare
   July 93         A NetWare Interface for Visual Basic
   
   The AppNotes can be obtained by contacting the Novell Research
   Order Desk, FAX: +1 303 294-0903, Voice 800 377-4136, +1 303 297-
   2725.  Address as follows:
   
   Novell Research Order Desk
   1601 Park Avenue West
   Denver, CO 80216-5199
   
   AppNotes are $95/year ($135 outside US)
   
   Here are a few books which might help you out to figure the calls
   out:
   
   Windows Development on NetWare Systems, Lori Gauthier and Sue
   Whitehead (c) 1994, Windcrest, Blue Ridge Summit, PA 17294-0850
   (McGraw-Hill) $34.95 Comes with disk This book also tells you how
   to "upgrade" to the currently supported SDK calls
   
   NetWare System Interface Technical Overview, Novell (c) 1990,1989
   (Addison-Wesley), $32.95 (describes Novell's C Network Compiler
   API's)
   
   Visual Basic Programmer's Guide to the Windows API, Daniel
   Appleman Ziff-Davis Press, 5903 Christie Ave, Emeryville, CA
   94608, $34.95  Comes with disk
   
   It should be mentioned that the APIs included with the NIVB are
   _not_ current, and for this purpose, you should get the Novell SDK
   kit. Also, Novell will not support NIVB, but you can sometimes get
   some helpfrom Compu$erve, or from others on the Infobahn <g>
   
   Good luck!
   
   p.s. It behooves you to become a member in the PDP (Professional
   Developer's Program) since you get the AppNotes (& Bullets!)
   for...free.
   
   p.p.s. Novell does NOT support the NIVB...
   
   p.p.p.s. Also, no docs come with it.  You'll probably need the
   Client C SDK kit to be able to really _use_ the code.
   
   p.p.p.p.s. To make things even better, the calls in NIVB are
   fairly old, and not of the Client C SDK kit variety.  However,
   there _are_ books which could help you out, e.g. "NetWare System
   Interface Technical Overview", by Novell. ISBN:0-201-57027-0,
   published by Addison-Wesley Publishing co, $32.95 US, $42.95 in
   Canada.
   
   Update:
   
   AppNotes are dead, however, Develper Notes live on.  There is one
   article about NetWare programming with Visual Basic here:
   
   July/Aug 94     NetWare Programming in Visual Basic:
                   Using Apiary's NetWare Client SDK for Visual Basic

19.  Visual Basic 4 news [**]
   
   Here is the news we have observed (and which was a guess in
   previous versions of this FAQ)
   
   a.   Two versions: 32-bit and 16-bit
      Like Visual C++ 1.5, VB 4 comes with compilers for the 16-bit API from
      Windows 3.1 as well as a real 32-bit compiler (or pseudocompiler) for
      Windows 95 (and NT) bundled together.
   
   b.   New features inherited from VBA
      
      1)   VB 4.0 is really VB Applications Edition 2.0
2)   Line continuation character " _" (space+underscore)
      
      3)   WITH statement, known from Pascal, to save typing and make code
           cleaner. An example:
        
             With Form1
               With Text1
                 Bold = true
                 FontName = "New Times Roman"
               End With
             End With
      
      4)   FOR EACH .. NEXT statement allows you to make changes to a group
           of objects at once better than FOR..NEXT. Syntax:
   
             For Each element In group
                     [statements]
                     [Exit For]
                     [statements]
             Next [element]
      
      5)   OPTIONAL statement allows you to leave some Variant parameteres
           undefined when calling a user-defined sub or function. Also an ARRAY
           function that returns an array form a list supplied as parametres, and
           a special optional ParamArray optional parameter of Variants.
      
      6)   Boolean data type. Coded as 16-bit (2-byte), but can only have
           TRUE or FALSE value.
      
      7)   Byte data type (8-bit). Can have values from 0 to 255.
8)   FUNCTION can be of user-defined type.
      
      9)   OLE Automation allows detailed control over objects taken from
           ie. Excel or Word.
      
      10)  Reusable Objects and Collections, called Classes
      
      11)  Property Procedures allows you to add custom properties to form
           and some other modules.
      
      12)  New enhanced development environment, which includes an object
           browser and allows add-ins. Pro edition also allows creation of your
           own add-ins. (For some strange reason, the 32-bit version of this does
           not use Win95 file dialog boxes!)
      
      13)  Conditional compilation: allows one source for 32- and 16-bit
           versions.
14)  Data bound DBList, DBCombo, and DBGrid controls! VB 4 uses Jet
2.5 engine.
   
   c.   VBX is dead. Long live OCX!
      
      You may not feel for celebrating this either, but the 32 bit VB 4 will
      not support the old 16-bit VBX'es. The 16-bit version of VB 4 will
      support them for backwards compatibility, but be aware that OLE 2 and
      OCX is the way of the future, at least if Microsoft gets it as they
      want.

20.  How do you change the icon and otherwise manipulate the DOS box?
   
   Enclosed is the results of my digging around to enable me to
   change the icon
   of a DOS box launched with the SHELL function. It illustrates most
   aspects
   of dealing with DOS boxes.
   
   Example of launching PIF file minimized and running it in the
   background (Needs Execute Background box checked in PIF file), and
   assigning the PIF file a new Icon rather than the default DOS Box
   Icon.
   
   (Note: it seems this method changes the icon of ALL the active DOS
   boxes)
   
   Code follows:
   x-----------------------------------------------------------------
   ----x
   Option Explicit
   
   Global Const SWP_NOSIZE = 1
   Global Const SWP_NOMOVE = 2
   Global Const SWP_NOACTIVATE = &H10
   Global Const SWP_SHOWWINDOW = &H40
   Global Const SWP_HIDEWINDOW = &H80
   Global Const SWP_FLAGS = SWP_NOMOVE Or SWP_NOSIZE Or
   SWP_NOACTIVATE
   Global Const SWP_SHOW = SWP_SHOWWINDOW Or SWP_FLAGS
   Global Const SWP_HIDE = SWP_HIDEWINDOW Or SWP_FLAGS
   Global Const HWND_BOTTOM = 1
   Global Const GCW_HICON = (-14)
   Global Const GCW_HMODULE = (-16)
   
   Declare Function GetModuleUsage Lib "Kernel" (ByVal hWnd%) As
   Integer
   Declare Function ExtractIcon Lib "Shell" (ByVal hInst%, ByVal
   lpExeName$,
   |ByVal hIcon%) As Integer
   Declare Function DestroyIcon Lib "User" (ByVal hIcon%) As Integer
   Declare Function FindWindow Lib "User" (ByVal lpClassName As Any,
   ByVal
   |lpCaption As Any) as Integer
   Declare Function SetWindowPos Lib "User" (ByVal h%, ByVal hb%,
   ByVal X%,
   |ByVal y%, ByVal cx%, ByVal cy%, ByVal F%) as Integer
   Declare Function GetClassWord Lib "User" (ByVal hWnd%, ByVal
   nIndex%)
   |As Integer
   Declare Function SetClassWord Lib "User" (ByVal hWnd%, ByVal
   nIndex%,
   |ByVal wNewWord%) As Integer
   
   Sub LaunchPif(PifFile as String, IconName as String)
       Dim Res As Integer     'Return value from API call
       Dim MyInst As Integer  'Instance handle for this app
       Dim PifIcon As Integer 'Pif Icon Resource name
       Dim OldIcon as Integer 'Original Pif Icon resource (default =
   0)
       Dim PifhWnd As Integer 'Dos Box Window handle
       'Launch PIF file
       PifInst = Shell(PifFile, 6)
       'Get Instance handle for main MDI Window (assumed to be
   frmMDI)
       MyInst = GetClassWord((frmMDI.hWnd), GCW_HMODULE)
       'Create new Icon resouce by loading Icon from disk file
       'Check Icon file exists
       If Dir$(IconName) <> "" Then
          'Make sure string is null terminated
          IconName = IconName & Chr$(0)
          'Create Icon resource in this window
          PifIcon = ExtractIcon(MyInst, IconName, 0)
       Else
          PifIcon = 0
       End If
       'Reset Default Icon on DOS Box to PifIcon
       'Check PIF file still running and Icon resource created
       If GetModuleUsage(PifInst) <> 0 and PifIcon > 0 Then
          'Get Pif Window handle
          PifhWnd = FindWindow(0&, "Window name in PIF file")
          'Set Icon handle to PifIcon resource
          OldIcon = SetClassWord(PifhWnd, GCW_HICON, PifIcon)
          'Hide and show window to get a redraw of the Icon
          Res = SetWindowPos(PifhWnd, HWND_BOTTOM, 0, 0, 0, 0,
   SWP_HIDE)
          Res = SetWindowPos(PifhWnd, HWND_BOTTOM, 0, 0, 0, 0,
   SWP_SHOW)
       End If
   
       'Wait for PIF file to complete
       Do While GetModuleUsage(PifInst) <> 0
          DoEvents
       Loop
   
       If PifIcon > 0 then
          'Reset Icon to original
          Res = SetClassWord(PifhWnd, GCW_HICON, OldIcon)
          'Tidy up by removing PIF Icon resource
          Res = DestroyIcon(PifIcon)
       Endif
   End Sub
   x-----------------------------------------------------------------
   ----x
   [Dr David Baird (BairdD@AgResearch.CRI.NZ)]

21.  How do I make the mouse cursor invisible/visible?
   
   Use the API call ShowCursor(False) or ShowCursor(True). Just be
   aware that the Windows cursor is a shared object, so if your
   process hides it then it must also redisplay it as well. Also the
   function is not truly "True" or "False" in nature - it is LIFO, so
   that if your process has for some reason set it "False" multiple
   times then you must set it "True" the same number of times in
   order to re-display the cursor. Hard to explain but play with it -
   you'll see what I mean...
   [Galen Raben (galenr@hpgrla.gr.hp.com)]

22.  How do I create controls dynamically (at run-time)?
   
   Search of VBKB_FT on "control* near array*" finds a number of
   articles, including Article ID: Q79029 "Creating Nested Control
   Arrays in Visual Basic" This is THE article to read to understand
   control arrays (plus a number of other neat concepts). In
   particular, look at the procedure "loadall_click".
   
   The key is that you need to create the first instance of
   your_control (ie. your_control(0)) at design time.
   [Ayn Shipley (ashipley@hookup.net)]

23.  How do I set the Windows wallpaper at runtime?
   
   I'm surprised this isn't in the FAQ yet. [ED: now it is!] You need
   the SystemParametersInfo API function and the SPI_SETDESKWALLPAPER
   constant.
   
   For this you will need the following constants and function
   declaration...
   
   Const SPI_SETDESKWALLPAPER = 20
   Const SPIF_SENDWININICHANGE = &H2
   Const SPIF_UPDATEINIFILE = &H1
   Declare Function SystemParametersInfo Lib "User" (ByVal uAction As
    |Integer, ByVal uParam As Integer, lpvParam As Any, ByVal
   fuWinIni As
    |Integer) As Integer
   
   'You then call the function as follows...
   
   Result% = SystemParametersInfo(SPI_SETDESKWALLPAPER, 0, ByVal
   BMPFile$,
    |SPIFlags%)
   
   '... where SPIFlags% is 0 if the change is not to be made
   permanent, or
   '(SPIF_UPDATEINIFILE Or SPIF_SENDWININICHANGE) if it is to be
   carried across
   'into future Windows sessions.
   
   NOTE: Please be certain to include the ByVal keyword before the
   bitmap
   filename, as this argument is declared as Any, NOT as ByVal
   String.
   [Luke Webber(webber@werple.apana.org.au)]

24.  How do I call help files from a VB program? [**]
   
   There are 2 ways you can display help files:
   1) In code
      a) Using the common dialog control
      b) Making a winhelp api call
      (see below for examples)
   2) Pressing F1 when App.HelpFile is set to your
      help file.
      Note - if a control's HelpContextID property is
      set to the context id of a help topic, that topic
      will be displayed if the control has focus and the
      user presses F1, otherwise the contents is displayed.
   
   (see Mapping Context-Sensitive Topics, Chapter 6 pg. 117
    of the Professional Features Book 1 for information on
    setting the context ids for your help file. Many help
    authoring tools will generate the context ids for you.)
   
   - Include constant.txt in your project
   - Set App.HelpFile = "c:\yourfile.hlp"
   - Declare the following function in a .bas module
     (make sure it is all on one line):
   
   'Function for display windows help files
   Declare Function WinHelp Lib "User" (ByVal hWnd As Integer,
   ByVal lpHelpFile As String, ByVal wCommand As Integer,
   dwData As Any) As Integer
   
   COMMON DIALOG:
   ---------------
   Note - The HelpContext property can only be assigned
   an integer. The equivalent WinHelp Api call can use a long.
   In this example the context id is 1000
   
   jump to a context id within help file.
     CMDialog1.HelpFile = "c:\yourfile.hlp"
     CMDialog1.HelpCommand = HELP_CONTEXT
     CMDialog1.HelpContext = 1000
     CMDialog1.Action = 6
   
   bring up contents
     CMDialog1.HelpFile = "c:\yourfile.hlp"
     CMDialog1.HelpCommand = HELP_CONTENTS
     CMDialog1.Action = 6
   
   bring up search window
     CMDialog1.HelpFile = "c:\yourfile.hlp"
     CMDialog1.HelpCommand = HELP_PARTIALKEY
     CMDialog1.HelpKey = ""
     CMDialog1.Action = 6
   
   quit help
     CMDialog1.HelpFile = "c:\yourfile.hlp"
     CMDialog1.HelpCommand = HELP_QUIT
     CMDialog1.HelpContext = 0
     CMDialog1.Action = 6
   
   
   WINHELP API:
   -----------------
   In the following examples iRetCde is declared as an integer.
   
   Jump to context id (e.x., context id is 1000)
     iRetCde = WinHelp(Me.hWnd, "c:\yourfile.hlp", HELP_CONTEXT,
   ByVal CLng(1000))
   
   bring up contents
     iRetCde = WinHelp(Me.hWnd, "c:\yourfile.hlp", HELP_CONTENTS,
   CLng(0))
   
   bring up search window
     iRetCde = WinHelp(Me.hWnd, "c:\yourfile.hlp", HELP_PARTIALKEY,
   ByVal "")
   
   quit help
     iRetCde = WinHelp(Me.hWnd, "c:\yourfile.hlp", HELP_QUIT,
   CLng(0))
   
   [Blake Miller (bemiller@amoco.com)]


E.   CALLING THE WINDOWS API AND DLLs IN GENERAL
  

1.   What is the Windows API?
   
   The Windows API (Application Program Interface) is a collection of
   Dynamic-Link Libraries (DLLs) that do most of the common things in
   Windows. Calls to the Windows API gives you access to routines
   that do things like drawing menu bars, manipulating bitmaps,
   playing sound files, and pretty much every other function of
   Windows.

2.   How do I call a DLL?
   
   Basically, you declare a DLL procedure which you can call in your
   VB program which in turn passes data to and/or retrieves data from
   the DLL. You should read the section of the VB manual that talks
   about calling DLLs ("Chapter 24  Calling Procedures in DLLs" in
   the VB 3.0 Programmer's Guide). This chapter covers the basics of
   using the Windows API DLLs and calling DLLs in general. Beyond
   that you may want to find a good book on this subject since it is
   too large to cover here (see the Book Listing in the Appendix of
   the General FAQ - Part 1). Don't be too intimidated!  Using DLLs
   (especially many of the Windows API functions) is quite easy, once
   you learn how to call them. In fact, many of the newer DLLs
   include VB-compatible modules!

3.   What about DLL calls that require callbacks?
   
   VB does not support callbacks, but various extensions can help.
   
   Dan Appleman's "Visual Basic Programmer's Guide to the Windows
   API" comes with a floppy disk which code samples and tools. It
   also includes a VBX which supports the callbacks which many API
   calls require. Dan is also founder and president of Desaware which
   sells more extensive tools, including SpyWorks, for VB developers.
   [Walter Hill (whill@netcom.com)]

4.   Tips for calling DLLs (such as the Windows API)
   
   
   a.   Using the BYVAL keyword is critical. Using it when you're
      supposed to call by reference and (more common) not using it when you
      are to give a value to the external function are the single most
      common mistakes. Wrong calling convention can often result in a
      General Protection Fault (GPF) or, even worse, corruption of another
      applications' data.
   
   b.   Check return and parameter types. For return types, a C function
      declared as "void" means you use a Sub not a Function.
   
   c.   Initialize strings by padding it to the necessary length! If you
      pass a string that is too short to the API it will happily write past
      the end of the string and possibly corrupt data.
   
   d.   Use Option Explicit. A typing error that results in a bug in the
      VB source will occasionally cause a GPF when you call external code.
e.   It's a jungle out there! Check parameter values as there is no
type checking outside VB. If you make a mistake, you'll often get a
GPF.
   
   f.   Save before you run! You may even need to restart Windows after a
      GPF, since DLL's often aren't unloaded properly. As a second option
      you can check out WPS (Windows Process Status) which is distributed
      with VB/Pro and placed in the CDK directory. This utility allows you
      to kick out any module (EXE, DLL) from memory (shooting yourself in
      the foot if you want to. WPS is a nice way to find out what DLLs are
      actually used, but save your work first!).


F.   VISUAL BASIC AND DATABASES
  

1.   Why can't I use an index with my VB accessed database?
   
   There is a mistake in the docs which says you can set the active
   index for a recordset. You can't. The data control uses the
   primary key for tables and physical order (I think) for dynasets.
   [Nic Gibson (nic@skin.demon.co.uk)]
   
   NOTE: You can of course set the indexes yourself using code in
   VB/Pro (Table objects), but Data Control's can't. Sorry for the
   problems this possible misunderstanding caused!
   
   Thanks to John McGuire (jmcguire@jax.jaxnet.com) for clarifying
   this.
   

2.   "Can't find installable ISAM" or Why does my compiled VB database
   app generate an error when it ran just fine in the design environment?
   
   You can thank Microsoft for documenting this topic so poorly. When
   you compile your VB database application, you must also have an
   INI file for it which provides the correct pointers to the
   appropriate database drivers. Therefore, if your application is
   named "INVOICE.EXE", you will need to have a properly configured
   "INVOICE.INI" file in your Windows directory. The file,
   EXTERNAL.TXT, that came with VB should explain all about it.

3.   Is the Access Engine and Visual Basic Pro good enough for
   database work?
   
   That, of course, depends. Generally the answer is "yes", but you
   may need some third-party add-on products.
   
   These are the major weaknesses of VBPro's database functions:
   
   a.   Limited data controls: No add, delete or search button; no bound
      list box or masked edit control and - the worst - no bound grid!
b.   No run-time query builder ("how good is your user in SQL?") or
report builder.
c.   No direct advanced control of the Access 1.1 (or 2) Database
Engine (ie. security, optimization, etc).
   
   d.   SQL us SLOW. Handcoding is much faster (but harder to code)
   
   The good news is that lots of companies are willing to sell you
   products which address one or more of the above weaknesses.
   
   Also, if you build a database application with advanced database
   relations, it can be a good idea to build the database itself with
   Access and the front-end with VB.

4.   How do you avoid the "Invalid use of null" error when reading
   null values from a database?
   
   If you try to retrieve a null value (empty field) from a database,
   you will get the error: "Invalid use of Null". Here is one way to
   get around this problem:
   
   I've worked around this problem with the following code:
   
     TextBox.Text = MyTest.Fields("TestFld") & ""
   
   This code converts the Null-Value into an empty string.
   [Ralf Metzing (rmm@dragon.stgt.sub.org)]

5.   What is "NULL"?
   
   Contrary to popular belief, Null is not nothing. It's even less
   than nothing.   8^)
   
   The VB documentation describes all the horrors of misunderstanding
   the infamous NULL. Since people don't read the documentation, we
   feel like informing that
   
     If ThisVarIsNull = NULL then DoSomething
   
   will *always* fail, and the DoSomething can't possibly be
   executed. You *must* use IsNull(ThisVarIsNull) which will return
   True if the var is Null (phew!).
   
   If you want to find out why someone came to think of this strange
   value, read some relational database theory.

6.   How can I access a record by record number?
   
   Use a counter or index field - or even better, a Bookmark property
   - for this.
   
   It is *impossible* to ask a relational database system to give you
   ie. "field number 3 in record number 10" since by definition a
   relational database does not have row or column numbers. Databases
   allowing direct access like that is not even remotely relational.
   
   Access (and therefore, VB) is about as close to a real relational
   database system as you can get.

7.   How about Access 2.0 compatibility?
   
   You need the compatibility layer availability. The file COMLYR.EXE
   is in the MSBASIC library on Compuserve. This file provides all
   the items necessary for compatibility between VB 3.0 and Access
   2.0.
   [Fred Griffin (72321.3230@compuserve.com)]
   
   For unknown reasons you can't install the compatibility layer
   without Acess 2.0 being installed, even if you just want to open a
   database from VB that was created by someone else.
   [Kent Boortz <boortz@sics.se>]
   
   The file COMLYR.EXE can be downloaded from ftp.microsoft.com. It
   is located in the directory /softlib/mslfiles. (NOTE: A "DIR" in
   this directory is rarely a wise course of action. There is an
   enormous amount of files im /mslfiles.)

8.   Tips for VB database programming:
   
   
   a.   Use Access and QBE. Once it's "working" (even if the parameters
      are hardcoded), then open up View.SQL and copy the stuff from the SQL
      window into your VB code. If you need to insert VB variables, try
      testing this under Access by using parameters instead. They're then
      nice & easy to spot when it comes to converting into VB - I always
      call my parameters "PR_xxxx", so I can just search my VB code for this
      to find any instances that I've missed.
   
   b.   It never works first time. So put an error handler into your VB
      code that copies the contents of SQLStr onto the clipboard, should the
      query fail. Now it's quick & easy to switch back to Access, find a
      scratch query and paste the erroneous SQL into that. It's *much*
      easier to debug a SQL query in Access, after the variables have been
      merged in, than it is to do it blind from VB.
   
   c.   Use carriage returns to break up your SQL. One before each
      reserved word is sensible. They're not significant in SQL. I assume
      you're not stupid enough to put them in the middle of field names -
      unfortunately Debug.Print is!
   
   d.   When merging in the contents of a variable (building a SQL query
      in a VB string), it should *always* be surrounded by an ampersand and
      3 double quotes, or an ampersand and 2 mixed quotes, depending on your
      local conventions:
      
        SQLStr = SQLStr & "WHERE Username <= """ & Username$ """ "
      
        or
      
        SQLStr = SQLStr & "WHERE Username <= '" & Username$ "' "
   
   e.   If you're using dates, then it will *always* be one quote, a hash
      and an ampersand:
      
        SQLStr = SQLStr & "WHERE Start_Date <= #" &
        |Format$(CutOffDate,"Long Date") & "# "
   
   f.   Another tip with dates is to format them with the long date
      format, not the short date. This is then safe against the
      transatlantic reversal of month & day position.
   
   g.   If you're merging in a field/table name, enclose it in square
      brackets. That way the SQL will still be valid if the variable
      contains spaces:
      
        SQLStr = "SELECT * FROM [" & TableName$ "] ;"
      
      When building SQL strings in VB, then you'll often do this on several
      lines, concatenating SQLStr with the new string. If you leave a space
      at the end of every string, then you can guarantee you won't have
      problems with the text from successive lines running into each other.
   
   h.   If you're using Access 1, you'll keep running into the 1024
      character limit on the length of a SQL string. Keep the table & field
      names short, especially if many JOINs are concerned. Using underscores
      in names is shorter than spaces, as you don't need the extra 2
      characters for the square brackets around them. If your SQL is
      slightly too long, then you'll probably see a "Missing semicolon"
      error, even though the semicolon is obviously there (To you, anyway!).
   
   i.   Making a QueryDef is a complicated process that is often slower
      than executing the query ! Don't mess with the .SQL property, as that
      is equally slow (Access needs to do a lot of work to turn SQL into its
      internal query format). Two ways around this: Use ready-built queries,
      written with Access. If you need to merge in values from variables,
      then use a query with parameters. Setting parameter values is quick to
      execute.
   
   j.   If you really need to build SQL on the fly -- you need to build
      an ad hoc query, or to supply table or field names (which can't be
      done with query parameters), then try using:
      
        database.Execute SQLStr
      
      As this doesn't build a QueryDef, then it's quick.
      [Tips a to j by Andy Dingley(dingbat@codesmth.demon.co.uk)]
   
   k.   Make sure all Tables, Dynasets, Snapshots, Databases, and other
      data access objects are properly closed before ending the program. As
      near as I can tell, the pointers to these objects are not destroyed if
      your VB program doesn't Close them (including when a program crashes).
      A Microsoft guy did say he can't find anything that confirms that they
      close, but (of course) he wouldn't say for certain that they aren't
      closed. Based on resources after serious crashes (that I couldn't walk
      the program out of by hand), I don't think they're automatically
      closed.
      [John McGuire (jmcguire@jax.jaxnet.com)]

9.   How come I get a "No Current Record" error when I use a a Data
   Control on an empty table?
   
   Well, this is a "feature" courtesy of Microsoft.  KB article
   Q106494 explains this in detail.  Basically, the workaround is to
   add an empty record to the table before the user can do anything
   (or before you try to do any Moves on the Table).
   [George Tatge (gat@csn.org)]

10.  How can I speed up my VB database application?
   
   KB article Q109830 gives some hints.  Things you should do
   include:
   
   - Use Snapshots when possible.
   - Use transactions whenever possible.
   - Use Dynasets when possible.
   - Use SQL action queries when possible.
   [George Tatge (gat@csn.org)]
   
   Major Weakness: SQL is SLOW! A hand-coded search (with indices) is
   MUCH faster than an equivalent SQL call, especially with complex
   search criteria. For example:
   
     SELECT * FROM Table WHERE SSN = '555-33-1234' AND Posted #01-31-
   95#
   
   is a lot slower than:
   
     Table.Index = "SSN"
     Table.Seek "=", "555-33-1234"
     If Not Table.NoMatch Then
       While Not Table.EOF
         If Table("SSN") "555-33-1234" Then
           Table.MoveLast  'Forces an EOF
         ElseIf Table("Posted") #01-31-95# Then
           'Do something
         End If
         Table.MoveNext
       Wend
     End If
   
   Granted, it is a LOT more code, but I ran a VERY similar query
   that took THIRTY HOURS! The equivalent hand-written code took
   ELEVEN MINUTES! That's 163 times faster! I think basically SQL
   isn't very good at figuring out which indexes to use (I also think
   I've read something to the effect that the newer version, 2.0 or
   2.5, IS better at this).
   [John McGuire (jmcguire@jax.jaxnet.com)]

11.  How do I get a bitmap picture in a field in an Access database?
   
   See p.466 of the Visual Basic (3.0) Programmer's Guide. It
   contains a section called "Using Bound Picture Box and Image
   Controls". Basically you have to bind the VB PictureBox to a field
   in the Access DB, set the .Picture property in the PictureBox, and
   then move to the next record or something. VB will then store your
   picture in Access in a form in which it can be retrieved by VB in
   the future.
   
   If you store the pictures in Access directly (using Access), VB
   won't be able to read them (using VB 3.0 and Access 1.1).
   
   You can also store the picture's filename as a text field in the
   database and use LoadPicture() to load that file into the VB
   PictureBox.
   [Tim Shea (shea@marcam.com)]

12.  What is "Reserved Error -1209"?
   
   You will get a Reserved Error [-1209] ("There is no message for
   this error")
   when your database is corrupted. Try opening the database using MS
   Access;
   if it's corrupted you should get the option to repair it.
   [Joe Abley (joe_abley@originuk.demon.co.uk)]
   
   You should also compact it, after repair. I recommend you add the
   following to your File menu on your main form:
   
     Case ...
     
       RepairDatabase Curentdatabasename
     
     Case ....
     
       On Error resume next
       Kill "temp.MDB"
       Name  curentdatabasename as "temp.mdb"
       on error goto errcompact
       compactdatabase "temp.mdb", Currentdatabasename
       kill "temp.mbd"
       exit sub
     
     errcompact:
       msgbox "compaction failed"
       name "temp.mdb" as Currentdatabasename
     
     Case ...
   
   [Ayn Shipley (ashipley@hookup.net) , Kym Wilson]

13.  "Cannot perform operation. illegal.." with Paradox 3.5 table(s)
   
   Your Paradox table must have a primary key, or it will be read-
   only no matter    what you set its properties to.
   [Ayn Shipley (ashipley@hookup.net)]

14.  I'm getting error message "Reserved Error [-nnnn] ("There is no
   message for this error")" from Jet Engine 2.0. Huh?
   
   See the Knowledge Base article Q117900 "Reserved Error Numbers
   Returned by
   the Jet 2.0 Engine" for a complete list of the new error messages.
   
   Extract:
   "Jet_Error/Message_String
      -1010 Invalid database ID.
      -1016 Can't have more than 10 fields in an index.
      -1029 Database engine hasn't been initialized.
      -1030 Database engine has already been initialized.
      -1034 Query support unavailable."
   [Ayn Shipley (ashipley@hookup.net)]

15.  Why do I get "object not an array" when I try reference the
   fields of a global object variable which I have set to a table?
   
   VB has a parser bug which makes it difficult to use database
   objects        declared in a module from within a form.
   
   WORKAROUND: Just perform some _method_ on the table object
   somewhere _before_ you try to reference fields. Say in a form-
   based subroutine AAAA_IllBeFirst you have a Tbl.MoveFirst, which
   is never even executed. Then VB suddenly realises what the object
   is and all is forgiven.
   
   Credit to Luke Webber and "Joe Foster of Borg".
   [Ayn Shipley (ashipley@hookup.net)]

16.  Steps for securing an Access 2.0 database [**]
   
   What I started with:
     A database that I wanted to make secure.
     Access 2.0 installed on my hard drive.
     No Access permissions or accounts ever played with under Access.
   
   1)  I ran MS Access Workgroup Administrator and created a new
       SYSTEM.MDA and assigned a unique workgroup id.
   
   2)  Ran Access and created a new database, DB1.MDB.
   
   3)  Changed the password for the Admin user using Change Password
   under
        the Security menu.  Changed the password from nothing to
   "PASSWORD".
   
   4)  Clicked on Users under Security.  Added a new user, "JOEUSER"
   and made
       it a member of the Admins and Users groups.
   
   5)  Closed Access, deleted the new database I had just created,
   DB1.MDB,
       and restarted Access.  Logged in as the new user, "JOEUSER".
   Created
       a new database named DB1.MDB.  Changed the password from
   nothing to=7F
       "PASSWORD".
   
   6)  From the File menu, clicked Add-ins and then Import Database.
   Imported
       my database, REAL.MDB, that I wanted to make secure.
   
   7)  Went to Permissions under the Security menu and turned off all
       permissions for all Groups and all Users for the database, all
   tables,
       forms, macros, etc.  The only permissions I left on was full
   permissions
       for all objects for the new user, "JOEUSER".  After changing
   the
       permissions, I closed Access (note that the database I just
   used was
       DB1.MDB).
   
   8)  I made a backup of my database REAL.MDB and renamed DB1.MDB to
   REAL.MDB.
   
   9)  Opened my VB code and added the line:
   
                SetDefaultWorkspace "JOEUSER", "PASSWORD"
   
       right before the line where I open the database.
   
   10) Copied the SYSTEM.MDA from my C:\ACCESS directory to the
   directory
       where my VB code is.  (Note, I do not have an INI file for my
   program).
   
   11) Ran my VB program and my database can be opened by my program
   and nobody
       else.  The SYSTEM.MDA has to be delivered with my program
   however.
   
   See SetDefaultWorkspace and SetDataAccessOption in VB help for
   more information on how to set up the data access paramaters in an
   INI file.  Make sure you add error handling for a missing or
   messed up SYSTEM.MDA file.
   
   I think this is a good basic way to prevent people from
   looking/changing your database.  Possible flaws are looking at a
   dump of the .EXE file and finding the name and password used to
   open the database (there are various workarounds for this) and
   also running a program to look at parameters passed when opening
   the database (don't know if this is possible and can't think of a
   workaround if it is).
   [Justin F. Smith (jsw117@psu.edu)]


G.   DISTRIBUTING VISUAL BASIC APPLICATIONS
  

1.   What are some tips for using Setup Wizard?
   
   There were loads of bugs in the setup utilities supplied with VB3.
   Be sure to get the newest version of SETUPKIT (usually called
   SETUPK.EXE or -.ZIP). It is available from the sources listed in
   the beginning of this document, and in the General FAQ.
   
   Alternatively, if you have the older versions, you may have to
   manually remove the line referring to OLE2UI.DLL in the file
   SETUPWIZ.INI. See later in this document for dates of newest files
   on ftp.microsoft.com.
   
   Follow the instructions in SETUPK.TXT exactly. The files actually
   belong in two separate directories. Not placing them correctly can
   create strange and unusual side effects -- none of them good(!)
   
   Set all involved EXE, DLL and VBX files to Read-Only so that the
   setup program doesn't modify them.
   [Charles F. Mulks (21667cfm@msu.edu)]
   
   A *very* good tip. Actually, make all executables on your system
   read-only. If not, you can get a sharing violation if you try to
   run the same DOS executable twice at the same time.
   
   Also, the source code for a SETUP program is *included* with VB3
   Pro. It is quite trivial to tailor it to your specific needs.
   
   The question remains: Is SetupWiz good? No! Good enough? Perhaps.

2.   Are there restrictions on what I can distribute with my VB
   program?
   
   The documentation tells what parts of the Visual Basic kit you can
   freely distribute: the VBX files, some DLL's and what the SetupKit
   includes on your distribution diskettes. Reading software license
   agreements may be more boring than asking the newsgroup, but is
   nevertheless a good idea. 8^)
   
   There have been some rumours on the newsgroup that you can't
   redistribute programs written with VB freely. This is nonsense.
   All applications created with VB can be redistributed freely
   without royalties (as long as you don't distribute proprietary
   external files).
   
   The rumours probably originated when Microsoft announced that they
   will not sell kits allowing third-party software to include the
   Visual Basic for Applications (VBA) system.

3.   What alternatives to setup wizard do I have?
   
   Perhaps the best one is to simply modify the setup app which is
   supplied with VB.  Look in your VB directory for the setupkit\
   setup1 directory.  There you will find everything you need to do a
   complete setup program.  This sample setup is coded to install a
   few sample app files and create a program group.  You can comment
   out those lines and change to your files and program mgr. group.
   There are also a few global variables you will want to change.
   All of this is contained in the comments in the code.
   
   Using this, and the distribution information in the manual telling
   you about which files to distribute with your app will make things
   much easier than using the setup wizard (IMNSHO).
   
   There are also several third party setup products available.
   [George Tatge (gat@csn.org)]

4.   Do I need to worry about users who have Progman replacements such
   as Norton Desktop and PC Tools?
   
   Earlier versions of those products and some others do not respond
   properly to the DLL commands to create groups and items.  More
   recent versions do.  All you can do in this case is to include
   some information in your readme.txt file that instructs users of
   those products to shut them down and start up program manager
   before installing.
   [George Tatge (gat@csn.org)]

5.   Can I distribute my app without vbrunXXX.dll?
   
   If you are sure that your users have it or can get it, you can
   easily distribute your app without vbrunXXX.dll.  Simply remove
   the file from your distribution disk or zip file and and ALSO
   remove it from the setup.lst file.
   [George Tatge (gat@csn.org)]

6.   Why won't my setup program install commdlg.dll et. al.?
   
   There are a couple of DLLs that are almost always in use by
   windows.  Commdlg.dll is the most common example.  When faced with
   this problem, there is no easy way out.  The full explanation is
   several pages long and beyond the scope of this FAQ.  The general
   idea is as follows:
   
   Your setup program will need to create a .BAT file to expand and
   then copy these files.  Then, it will need to shutdown Windows
   (see ExitWindowsExec API call) and run the .BAT file.  Then it
   will need to restart windows and continue your setup program.
   Your setup program should delete the temporary .BAT file that is
   no longer needed.
   [George Tatge (gat@csn.org)]

7.   Where do I install VBXs and DLLs?
   
   PLEASE- this is one place where everybody's life is much easier if
   you will follow Microsoft's recommendations.  All PUBLIC VBXs and
   DLLs should be installed in the windows/system directory!  A
   "PUBLIC" DLL or VBX is any which can be purchased on the open
   market.  In other words, if another VB programmer might possibly
   use the same VBX or DLL, install it in the
   system directory.
   
   If you have written private VBXs or DLLs that will never be used
   by any program but yours, you can install them in the same
   directory where you install your application files.
   
   There are lots of good reasons for doing this, but it makes a
   short novel to rehearse them all.
   [George Tatge (gat@csn.org)]


H.   MISCELLANEOUS TIPS AND INFORMATION
  

1.   Multiple identifiers after the DIM statement can be confusing
   
   Some programmers with background from Pascal can try the following
   
     Dim iA, iB, iC as Integer
     
   and think that all these 3 variables end up as Integer. In fact,
   the first two end up as default data type, normally Variant.
   
   Instead you should do
   
     Dim iA as Integer
     Dim iB as Integer
     Dim iC as Integer
     
   which takes up more space, but gives you room to comment your
   variables (hint, hint); *or*
   
     Dim iA%, iB%, iC%
     
   which does the whole job.

2.   "Clean up" your project before final EXE compilation.
   
   When you are ready to compile your VB project into your 'finished'
   EXE, be sure to save the project files, exit VB, restart Windows,
   run VB, load your project and go straight to compiling. Otherwise,
   your EXE may be larger in file size than necessary due to
   'garbage' getting included in the EXE. For some reason, VB does
   not fully clean up all of the previously used variables or objects
   that you may have been playing with while developing your program
   so these get included in your EXE even though they aren't used.
   Other VB users have even advocated saving all the project files as
   ASCII, then loading the ASCII files before compiling to further
   "clean up" the resulting EXE file.

3.   Multiple END statements can be dangerous; or, The program that
   refused to terminate.
   
   Suggestion: put the END statement used to exit your program *only*
   in the Form_Unload event of the main form. Whenever you want to
   end the program, just tell the main form to unload.
   
   Some have reported that after their program have (supposedly)
   terminated, it still appears in the task list. This can happen if
   you only hide secondary forms and forget to unload them when you
   end/unload the main form.
   
   Also note that the Stop-button on the button-bar of the integrated
   development environment doesn't really unload anything. It *nukes*
   the program, which generally is a good idea since it could be a
   bug in it that caused it to be stuck in an eternal loop or
   something.

4.   What are the latest versions of the various files used by VB?
   
   Date       File to download  Updates files   Description
   3/7/94     BTR110.EXE        BTRV110.DLL     Btrieve IISAM Driver
   3/7/94     DATAINDX.EXE      DATAINDX.DOC    "Data Access Guide"
                                                Index
   3/7/94     GENERIC.EXE       \VB\CDK\GENERIC Sample custom control
                                                source
   3/7/94     VBGRID.EXE        GRID.VBX        Grid control
   3/7/94     VBHC505.EXE       HC.EXE, HCP.EXE WinHelp compiler
   3/7/94     MSAJT.EXE         MSAJT110.DLL    Access Database Engine
   3/8/94     MSCOMM.EXE        MSCOMM.VBX      Serial
                                                Communications\control
   3/7/94     ORA110.EXE        ORACLE.TXT      Updated ORACLE.TXT file
   6/27/94    SETUPK.EXE        SETUP.EXE       Setup Toolkit
   3/7/94     VBRUN300.EXE      VBRUN300.DLL    Visual Basic Runtime
                                                Library
   3/7/94     XBS110.EXE        XBS110.DLL      XBase IISAM Driver
   
   There is an article in the Microsoft Knowledge Base that points to
   each of these files and provides more detailed information about
   the update. To find these articles, query the Microsoft Knowledge
   Base using the file name and the word "update3.00".
   
   Note the NEW SETUPKIT update!
   [Thanks to Marks Harrop <harrop@werple.apana.org.au>]
   
   Please inform the FAQ maintainer about newer versions.


I.   VISUAL BASIC FOR APPLICATIONS (VBA)
  

1.   Any tips for VB/Win 3 programmers moving to VBA?
   
   You are in for some surprises. VBA is more unlike VB 3 than most
   people thought. Especially the development environment is very
   different, and the language puts more emphasis on objects. The
   latter is a trend you can get used to for VB also.
   
   For Excel 5 VBA, be aware that the environment is based on the
   "workbook" idea Microsoft stole from Borland. Your controls will
   be placed in one sheet, and the code will be in another.
   Doubleclicking on the control to open the code window doesn't
   help. You have to use the "Tools|Assign Macro" menu option.
   
   Also, be aware that the list of events is nowhere close to what
   VB3 supports! No GotFocus, no MouseMove, no nothing. You'll be
   very confused if you try to look for "events" in the VBA docs!

2.   Does VBA support VBXs?
   
   No. If Microsoft have its way, VBX is a dead end. There will never
   be 32-bit VBXs, but OCXs using OLE 2. VBA is more a subset of VB 4
   than VB 3, but it does not fully support OCX yet. It will, though.

3.   How do I access properties on my dialog boxes in VBA?
   
   As noted above, VBA is a culture chock to VB programmers. If you
   create a textbox in VBA, call it txName and try to
     
     cMyVar=txName.Text
   
   the impolite interpreter will give you a "variable not defined"
   error.
   
   The magic is objects. You have to
     
     Dim txName as Object
     Set txName = DialogSheets("NameDialog".EditBoxes("txName"))
   
   And then you can access your properties like you used to in good
   ol' VB 3. (Anyone volunteer to beat senseless the guy who thought
   out this?)

4.   How do I use database routines from Excel VBA?
   
   The documentation is somewhere between sparse and inexistant on
   this topic. Any info on VBA and SQL would be much appreciated.
   
   Here Microsoft breaks the tradition and you *can't* use database
   objects, at least not the way you do in VB. Also, forget dynasets.
   
   I know nothing about databases in VBA. I just bring on the
   following tips from various magazines:
   
   Both SQLOpen and QueryGetData require a 'connection string'.
   That's about what the doc's say about the parameter. What is it?
   The doc is also tragically void of useful examples. Someone dug up
   the following example:
   
     "DSN=My data file;DBQ=c:\access\data.mdb;FIL=RedISAM;"
   
   which is about as understandable as it looks. If you use an empty
   string, you get a dialog which also can give you the string into a
   spreadsheet cell.
   
   Also, search for SQLREQUEST in the *main* help file for Excel 5
   (not the VBA help!) for these examples of connection_string's:
   
   dBASE             DSN=NWind;PWD=test
   SQL Server        DSN=MyServer;UID=dbayer;PWE=123;Database=Pubs
   ORACLE            DNS=My Oracle Data Source;DBQ=MYSER VER;
                     |UID=JohnS;PWD=Sesame
   
   There's a KnowledgeBase on Excel 5 on ftp.microsoft.com. Last time
   I looked, it was void of database stuff. Still, it may be a good
   idea to download it as the situation may have changed now.
   
   
   *** END OF VB/WIN FAQ DOCUMENT ***

-- 
Kris Nosack      knosack@park.uvsc.edu

>>>--->  Be strange, but not a stranger!  <---<<<

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Last Update March 27 2014 @ 02:12 PM