Q314746: BUG: Access Violation Occurs in ADO When You Run Executable File

Article: Q314746
Product(s): Microsoft Visual Basic for Windows
Version(s): 2.1,2.5,2.6,2.7,6.0
Operating System(s): 
Keyword(s): kbGrpDSVBDB kbGrpDSMDAC kbDSupport
Last Modified: 02-JAN-2002

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The information in this article applies to:

- Microsoft Visual Basic Enterprise Edition for Windows, version 6.0 
- Microsoft Visual Basic Professional Edition for Windows, version 6.0 
- ActiveX Data Objects (ADO), versions 2.1, 2.5, 2.6, 2.7 
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SYMPTOMS
========

You receive an access violation in ADO under the following circumstances:

1. Call the Debug.Print method on certain properties of the ADO Recordset
  object.

2. Compile the project.

3. Run the file as an executable (.exe) file.

CAUSE
=====

This problem occurs because the compiler does not remove the Debug.Print
statement correctly.

RESOLUTION
==========

To resolve this problem, use one of the following methods:

- Remove the Debug.Print statement from the code.

- Store the property value in a variable.

STATUS
======

Microsoft has confirmed this to be a bug in the Microsoft products listed at the
beginning of this article.

MORE INFORMATION
================

Steps to Reproduce Behavior
---------------------------

1. Create a new Standard EXE project in Visual Basic.

2. Add two CommandButton controls to the form. Specify the caption "Open
  Recordset" for Command1. Specify the caption "Close Application" for
  Command2.

3. On the Project menu, click Reference, and then select the "Microsoft ActiveX
  Data Object 2.x" check box.

4. Add the following code to the form:

  Option Explicit
  Dim cn As ADODB.Connection

  Private Sub Command1_Click()
      Dim rs As ADODB.Recordset
      Set rs = New ADODB.Recordset
      
      rs.Open "Select * from Customers", cn, adOpenDynamic, adLockBatchOptimistic
      
      Debug.Print "Update: " & rs.EOF
      
      rs.Close
      Set rs = Nothing
      
  End Sub

  Private Sub Command2_Click()
      Unload Me
  End Sub

  Private Sub Form_Load()
      Set cn = New ADODB.Connection
      cn.Open "User ID=sa;password=sa;Initial Catalog=pubs;Data Source=mySQLServer"
  End Sub

5. Modify the connection string as appropriate for your environment.

6. Compile and run the executable file.

7. Click Open Recordset.

8. Click Close Application. Notice that an access violation occurs.

9. To resolve this problem, use one of the following methods:

   - Comment out the Debug.Print line of code, and then repeat steps 5 through
     7.

   - Replace the code

      Debug.Print "Update: " & rs.EOF

     with the following code:

  Dim b as boolean
  b = rs.eof
  Debug.Print "Update: " & b

Additional query words:

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Keywords          : kbGrpDSVBDB kbGrpDSMDAC kbDSupport 
Technology        : kbVBSearch kbAudDeveloper kbADOsearch kbADO210 kbADO210sp1 kbADO210sp2 kbADO250 kbADO260 kbZNotKeyword6 kbZNotKeyword2 kbVB600Search kbVB600 kbVB600SP3 kbVB600SP4 kbVB600SP5 kbADO260SP1 kbADO270
Version           : :2.1,2.5,2.6,2.7,6.0
Issue type        : kbbug
Solution Type     : kbnofix

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