BUG: No Error Produced when Data Changed in DataControl

• Microsoft Visual Basic Standard and Professional Editions for Windows, version 3.0
• Microsoft Jet 2.0/Visual Basic 3.0 Compatibility Layer

SYMPTOMS

This article describes a scenario where two or more Visual Basic applications using the Microsoft Jet 2.0/Visual Basic 3.0 Compatibility Layer to edit and update the same record at the same time fail to produce error message 3197: "Data has changed; operation stopped."

STATUS

Microsoft has confirmed this to be a bug in the Standard and Professional Editions of Visual Basic for Windows, version 3.0, and the Jet 2.0/Visual Basic 3.0 Compatibility Layer. 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

1. On a computer with the Visual Basic 3.0 Compatibility Layer installed, start a new project in Visual Basic. Form1 is created by default.



2. Add a text box (Text1), command button (Command1), and data control (Data1) to the form.



3. Set the following properties of each of the controls according to the table listed below:




Control    Property       Setting       Comment
---------  -------------  -----------   --------------------------------------
Data1      DatabaseName   BIBLIO.MDB    Sample MDB in the VB directory.
Data1      RecordSource   Authors       The Authors table is in BIBLIO.MDB.
Text1      DataSource     Data1         Bind the text box to the data control.
Text1      DataField      Author        Put author's name in the text box.
Command1   Caption        Update        What the button does. 

4. Place the following code in the Click() event for the command button:

   
         Sub Command1_Click()
            Data1.RecordSet.Update
         End Sub 




5. Choose Make EXE File from the File menu, and compile the program as "DATAERR.EXE". Choose OK.



6. Exit Visual Basic, saving and naming the .MAK and .FRM files. In the Program Manager, choose Run from the File menu. Type "C:\VB\DATAERR.EXE" in the prompt and choose OK. Repeat this step so that you have two instances of the application running.



7. In the first instance, make a change to the author's name and choose Update (do not choose the data control).



8. In the second instance, make a different change to the author's name and choose Update. Notice that you did not get error message 3197 "Data has changed; operation stopped" as you should have.

WORKAROUND

To work around this problem, add the following lines of code to your Form_Load Event().

   Data1.Refresh        'Make sure the DatabaseName and RecordSource
                        'properties are set before you do this.
   Data1.RecordSet.Edit
   Data1.RecordSet.Update 

Additional query words: 3.00

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