DOCUMENT:Q171487 11-JAN-2001 [vbwin] TITLE :FIX: Crash When Assigning Uninitialized Object to Tag PRODUCT :Microsoft Visual Basic for Windows PROD/VER:5.0 OPER/SYS: KEYWORDS:kberrmsg kbVBp500 kbVS97sp2fix kbGrpDSVB kbvbp500sp2fix ====================================================================== ------------------------------------------------------------------------------- The information in this article applies to: - Microsoft Visual Basic Learning Edition for Windows, version 5.0 - Microsoft Visual Basic Professional Edition for Windows, version 5.0 - Microsoft Visual Basic Enterprise Edition for Windows, version 5.0 ------------------------------------------------------------------------------- SYMPTOMS ======== Attempting to set the Tag property of one of the Windows Common Controls (COMCTL32.OCX) at run-time may result in the following error and cause the application to terminate: "VB5 caused an invalid page fault in module COMCTL32.OCX at 0137:202cb2a8." CAUSE ===== This problem occurs when the object variable that you are trying to assign to the Tag property is uninitialized or is null. RESOLUTION ========== In Visual Basic 5.0, you can work around the problem by checking the value of the variable before assigning it to the Tag property: Dim x As Object '... If x Is Nothing Then ' Else StatusBar1.Panels(1).Tag = x End If STATUS ====== Microsoft has confirmed this to be a bug in the Microsoft products listed at the beginning of this article. This bug has been fixed in Visual Studio 97 Service Pack 2. For more information on the Visual Studio 97 Service Pack 2, please see the following article in the Microsoft Knowledge Base: Q170365 INFO: Visual Studio 97 Service Packs - What, Where, and Why For a list of the Visual Basic 5.0 bugs that were fixed in the Visual Studio 97 Service Pack 2, please see the following article in the Microsoft Knowledge Base: Q171554 INFO: Visual Basic 5.0 Fixes in Visual Studio 97 Service Pack 2 MORE INFORMATION ================ With Visual Studio 97 Service Pack 2 installed, the above scenario correctly yields with the following trappable run-time error. Run-time error '91': Object variable or With block not set. Additional query words: listview toolbar treeview ====================================================================== Keywords : kberrmsg kbVBp500 kbVS97sp2fix kbGrpDSVB kbvbp500sp2fix Technology : kbVBSearch kbAudDeveloper kbZNotKeyword6 kbZNotKeyword2 kbVB500Search kbVBA500 kbVB500 Version : 5.0 Issue type : kbbug Solution Type : kbfix ============================================================================= THE INFORMATION PROVIDED IN THE MICROSOFT KNOWLEDGE BASE IS PROVIDED "AS IS" WITHOUT WARRANTY OF ANY KIND. MICROSOFT DISCLAIMS ALL WARRANTIES, EITHER EXPRESS OR IMPLIED, INCLUDING THE WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE. IN NO EVENT SHALL MICROSOFT CORPORATION OR ITS SUPPLIERS BE LIABLE FOR ANY DAMAGES WHATSOEVER INCLUDING DIRECT, INDIRECT, INCIDENTAL, CONSEQUENTIAL, LOSS OF BUSINESS PROFITS OR SPECIAL DAMAGES, EVEN IF MICROSOFT CORPORATION OR ITS SUPPLIERS HAVE BEEN ADVISED OF THE POSSIBILITY OF SUCH DAMAGES. SOME STATES DO NOT ALLOW THE EXCLUSION OR LIMITATION OF LIABILITY FOR CONSEQUENTIAL OR INCIDENTAL DAMAGES SO THE FOREGOING LIMITATION MAY NOT APPLY. Copyright Microsoft Corporation 2001.