FIX: Attempting to Refresh Null TableDef Field Causes GP Fault

ID: Q94773

The information in this article applies to:

Microsoft Visual Basic programming system for Windows, version 2.0

SYMPTOMS

A general protection (GP) fault occurs when you attempt to refresh a Null Fields collection of a TableDef. Instead, you should receive this error:

"Method not applicable to this object."

When the Fields collection for a TableDef is not Null, the Refresh method works as expected.

STATUS

Microsoft has confirmed this to be a problem in Microsoft Visual Basic version 2.0 for Windows. This problem was corrected in Microsoft Visual Basic version 3.0 for Windows.

MORE INFORMATION

The following steps reproduce the problem:

Start the Professional Edition of VB.EXE with ODBC support already installed.

Add the following code to the Form_Click event procedure of Form1:


   Form_Click ()
   Dim db As Database
   Dim tDef As TableDef
   DBName$ = "Server1"
   Set db = OpenDatabase(DBName$)   '* DBName$ name of Database
                                    '* that is already setup on
                                    '* the SQL Server. This
                                    '* DBName$ should be set to
                                    '* server name that listed in
                                    '* the ODBC.INI file.
   Set tDef = db.TableDefs(0)

   Set db = OpenDatabase(DBName$)
   tDef.Fields.Refresh      '* This should result in a
                            '* error, but instead results
                            '* in a GP Fault.
   End Sub

In order to reproduce the problem, the first TableDef in the database, TableDefs(0), cannot have any fields associated with it.

Press the F5 key or ALT+R+S.

At this point, a GP fault occurs -- usually at address 0008:0083 in VBODBCA.DLL.

To avoid the problem, make sure the Fields collection is not Null before using the Refresh method. To do this, replace the tDef.Fields.Refresh statement in step 2 above with the following code:


   If Not tDef.Fields = Null Then
      tDef.Fields.Refresh
   End If

Additional query words: 2.00 3.00 GPF buglist2.00 fixlist3.00

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