PRB: ISAM Tuning Information Not Read From VB.INI

ID: Q150942

The information in this article applies to:

Microsoft Visual Basic Standard, Professional, and Enterprise Editions, 16-bit and 32-bit, for Windows, version 4.0

SYMPTOMS

The ISAM tuning information is not automatically read from the VB.INI file in the design environment or the <application>.INI in the executable program.

When using Visual Basic 4.0 with one of the ISAM drivers, unexpected behavior or errors occur. For example, setting Deleted=on in the [dBase ISAM] section of the VB.INI or <application name>.INI has no effect on the visibility of deleted records. Also, when trying to connect to a Paradox 4.x table, Visual Basic gives the error message:

Can't open this Paradox 4.x table because ParadoxNetStyle is set to 3.x in.

For developers working with Paradox 4.X tables, this means that their applications cannot access those tables at design time. Specifically, right clicking on a DBGrid and selecting "Retrieve Fields" will generate the error message described above. Also, the DataField property of bound controls will not be populated automatically. This means that the DataField property cannot be filled by selecting from the drop-down list of fields in the table. However, the field can still be entered at design time by typing it in. If the DBEngine.IniPath property is correctly assigned and contains the necessary information, the application will behave properly at run time.

Both the 16-bit and 32-bit versions of the Visual Basic database engine look for the [Installable ISAM] information, such as the [Paradox ISAM] and [dbase ISAM] sections, in the system registry. The 32-bit edition also looks for the ISAM tuning information in the system registry. The 16-bit version does not.

The 16-bit edition looks for the ISAM tuning information in a specified INI file. Unlike Visual Basic 3.0, it does not default to the VB.INI file or <application>.INI file.

STATUS

This behavior is by design.

WORKAROUND

To work around this problem in the 16-bit edition of Visual Basic, specify an .INI file that contains the ISAM entries using the INIPath property of the DBEngine object, and set all properties at run-time. For example:


   Sub Form_Load ()

      'Do before any other references to DAO objects or data control.
      DBEngine.INIPath = "VB.INI"
      'All other code

   End Sub

To work around this problem in the 32-bit edition of Visual Basic, specify a Registry key such as:


   ...\Engines\SomeISAM

where SomeISAM = Xbase, Paradox, Excel, Text, or Lotus, and the ... specifies any Registry key you specify.

Use the DBEngine.INIPath property as documented above to point to the Registry Key up to, but not including, the Engines Key (the ...).

If ... = "HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Jet\3.0", then the settings are system wide and DBEngine.INIPath does not need to be used.

NOTE: The full path to the .Ini file must be included, Visual Basic will not automatically look in the Windows directory.

For further information see:

"The Jet Database Engine Programmer's Guide", Appendix C.

Additional query words: 4.00 vb4win vb4all

Keywords : kbDatabase kbIISAM
Version : 4.00
Platform : WINDOWS
Issue type :