Knowledge Base

BUG: Data Control Errors Do Not Populate Error Object

Article ID: 129799

Article Last Modified on 12/9/2003

Microsoft Visual Basic 4.0 Standard Edition
Microsoft Visual Basic 4.0 Professional Edition
Microsoft Visual Basic 4.0 Professional Edition
Microsoft Visual Basic 4.0 16-bit Enterprise Edition
Microsoft Visual Basic 4.0 32-Bit Enterprise Edition

This article was previously published under Q129799

SYMPTOMS

A "Type Mismatch" error is generated when a control is bound to a field with an incompatible type, but the Error object is not populated when it is examined in the Data Control Error event.

CAUSE

This is a limitation of the Data Control in Visual Basic version 4.0. When the DAO generates an error, the Error object is cleared when the Error event for the Data Control is fired.

RESOLUTION

For more information, search for the "Trappable Data Access Errors" in the Help menu when building your error handling code.

You are not prevented in any way from writing the exact same error handling code you would have written previously. Note that the error number passed as a parameter to the Data Control's Error will be correct. Only the Error object is affected. Also, most error checking in the DAO will be unaffected. If a Field or Database object generates the error, then the Error object is properly populated.

STATUS

Microsoft has confirmed this to be a problem in the Microsoft products listed at the beginning of this article. We are researching this problem and will post new information here in the Microsoft Knowledge Base as it becomes available.

MORE INFORMATION

Steps to Reproduce Problem

Start a new project in Visual Basic. Form1 is created by default.
Add a data control (Data1) and a check box (Check1) to Form1.

Set the following properties for the controls:

   Control   Property       Value
   -----------------------------------
   Data1     Databasename   Biblio.MDB
   Data1     RecordSource   Authors
   Check1    DataSource     Data1
   Check1    DataField      Author

Add the following code to the Data1_Error procedure.

   Private Sub Data1_Error(DataErr As Integer, Response As Integer)
      Debug.Print "DataErr = "; DataErr
      Debug.Print "Description = "; Err.Description
      Debug.Print "HelpContext = "; Err.HelpContext
      Debug.Print "HelpFile = "; Err.HelpFile
      Debug.Print "Number = "; Err.Number
      Debug.Print "Source = "; Err.Source
      'Response = vbDataErrContinue
   End Sub

Start the program by clicking Start on the Run menu or by pressing the F5 key.

The program immediately generates a "Type Mismatch" error and pops up a dialog. The information in the Debug window looks like this:

DataErr = 13
Description =
HelpContext = 0
HelpFile =
Number = 0
Source =

If the Response = vbDataErrContinue is added to the program, the dialog will not pop up, but the output will be the same.

Additional query words: 4.00 buglist4.00 vb4win vb4all

Keywords: kbbug KB129799