BUG: Memory Leak When You Bind a Recordset to Visual Basic Intrinsic Controls (308644)

SYMPTOMS

If your Visual Basic application includes Visual Basic intrinsic controls (such as TextBox controls) on the form, when the code repeatedly binds a Recordset object to the control with the DataSource property of the control, you may notice that memory usage grows while the application runs.

RESOLUTION

A supported hotfix is now available from Microsoft, but it is only intended to correct the problem that this article describes. Apply it only to systems that are experiencing this specific problem.

Note You must have a Visual Studio license agreement to obtain this hotfix.

To resolve this problem, contact Microsoft Product Support Services to obtain the hotfix. For a complete list of Microsoft Product Support Services telephone numbers and information about support costs, visit the following Microsoft Web site:

http://support.microsoft.com/contactus/?ws=support

Note In special cases, charges that are ordinarily incurred for support calls may be canceled if a Microsoft Support Professional determines that a specific update will resolve your problem. The usual support costs will apply to additional support questions and issues that do not qualify for the specific update in question. The English version of this fix should have the following file attributes or later:

   Date        Time  Version      Size     File name
   ----------------------------------------------------
   25-Sep-2001 8:03  6.0.93.63    1.33 MB  MSVBVM60.dll  
   25-Sep-2001 8:03  6.0.93.63    1.79 MB  VB6.exe

MORE INFORMATION

Steps to Reproduce Behavior

Create a new Standard EXE application in Visual Basic. Form1 is created by default.
On the Project menu, click References. Select the Microsoft ActiveX Data Objects 2.x Library check box, and then click OK.
Place a TextBox control and a CommandButton control on Form1. Keep the default names for these two controls.

Add the following code to the code window of Form1:

Option Explicit

Private mRecordset  As ADODB.Recordset

Private Sub ClearDataSource()
    Text1.DataField = vbNullString
    Set Text1.DataSource = Nothing
    Set mRecordset = Nothing
End Sub

Private Sub Command1_Click()

    Dim lOffset As Integer
    
    For lOffset = 1 To 100 Step 1
        ClearDataSource
        CreateADO
        Text1.DataField = "firstname"
        Set Text1.DataSource = mRecordset
    Next lOffset
End Sub

Private Sub CreateADO()
    Set mRecordset = New Recordset
    mRecordset.CursorLocation = adUseClient
    mRecordset.LockType = adLockBatchOptimistic
    Set mRecordset.ActiveConnection = Nothing

    mRecordset.Fields.Append "firstname", adVarChar, 10
    mRecordset.Open 
    mRecordset.AddNew
    mRecordset(0) = "Joe"
    mRecordset.MoveFirst
End Sub

Build and run the application.
Click the command button repeatedly. Use Performance Monitor or Task Manager to monitor the memory usage.