Q198938: PRB: MSFLexGrid Redraw May Not Function Correctly

Article: Q198938
Product(s): Microsoft Visual Basic for Windows
Version(s): WINDOWS:6.0
Operating System(s): 
Keyword(s): kbCtrl kbVBp600 kbGrpDSVBDB
Last Modified: 11-JAN-2001

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The information in this article applies to:

- Microsoft Visual Basic Learning Edition for Windows, version 6.0 
- Microsoft Visual Basic Professional Edition for Windows, version 6.0 
- Microsoft Visual Basic Enterprise Edition for Windows, version 6.0 
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SYMPTOMS
========

After setting the TopRow property of the MSFlexGrid, setting the Redraw property
to True does not cause the MSFlexGrid to be automatically redrawn.

CAUSE
=====

Microsoft is researching this problem and will post new information in the
Microsoft Knowledge Base as it becomes available.

RESOLUTION
==========

There are a couple of workarounds to this problem. You can use the code in these
workarounds in place of the code shown in the MORE INFORMATION section of this
article

1. If you replace the MSFlexGrid1_Click() event in the MORE INFORMATION section
  with the following code, it works as expected:

     Private Sub MSFlexGrid1_Click()

       With MSFlexGrid1

         .Redraw = True
         If .Row = .Rows - 1 Then
           .TopRow = 2
           Debug.Print "Right After Setting .Top Row:  " & .TopRow

         End If

       End With

       Debug.Print "After leaving With block: " & MSFlexGrid1.TopRow

     End Sub

-or-

2. Using the above workaround will get the MSFlexgrid to move to the correct
  position. However, doing so may cause the grid to flicker when filling. To
  avoid this flickering you can use the LockWindowUpdate API call as noted in
  the below code. Instead of using the above code, replace the code in the
  MSFlexGrid_Click() event with the following:

     Private Declare Function LockWindowUpdate Lib "user32" _
           (ByVal hwndLock As Long) As Long

     Private Sub fgrItemGrid_Click()

       lres = LockWindowUpdate(Me.hWnd) 'Lock repaints

       With fgrItemGrid

         .Redraw = True
         If .Row = .Rows - 1 Then
           .TopRow = 2
           Debug.Print "Right After Setting .Top Row:  " & .TopRow

         End If

       End With

       lres = LockWindowUpdate(0&) 'Release Lock

       Debug.Print "After leaving With block: " & fgrItemGrid.TopRow

    End Sub

NOTE: The LockWindowUpdate API can be used to enable or disable a window from
repainting. In workaround 2 above, it is used to prevent the window from
repainting.

STATUS
======

Microsoft is researching this problem and will post new information here in the
Microsoft Knowledge Base as it becomes available.

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

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

1. Start a new Visual Basic 6.0 standard EXE.

2. From the Project menu, choose Components and add a reference to the Microsoft
  FlexGrid Control 6.0.

3. Add an MSFlexGrid to the default form.

4. Cut and paste the following code into the form:

     Private Sub MSFlexGrid1_Click()

       With MSFlexGrid1

         .Redraw = False
         If .Row = .Rows - 1 Then
           .TopRow = 2
           Debug.Print "Right After Setting .Top Row:  " & .TopRow

         End If
         .Redraw = True
         '.Refresh

       End With

       Debug.Print "After leaving With block: " & MSFlexGrid1.TopRow

     End Sub

     Private Sub Form_Load()
       With MSFlexGrid1
         .RowHeightMin = 288
         .Cols = 10
         .Rows = 5
         .TextMatrix(0, 1) = "Row 0"
         .TextMatrix(1, 1) = "Row 1"
         .TextMatrix(2, 1) = "Row 2"
         .TextMatrix(3, 1) = "Row 3"
         .TextMatrix(4, 1) = "Row 4"
         .Width = 4095
         .Height = 1600
       End With
     End Sub

5. Click on the "Row 4" cell. The code in the Click event will execute. However,
  the grid will not refresh and move up so that the TopRow is now 2.

  NOTE: Forcing a refresh with the .Refresh method does not correct this
  problem.

Additional query words:

======================================================================
Keywords          : kbCtrl kbVBp600 kbGrpDSVBDB 
Technology        : kbVBSearch kbAudDeveloper kbZNotKeyword6 kbZNotKeyword2 kbVB600Search kbVBA600 kbVB600
Version           : WINDOWS:6.0
Issue type        : kbprb

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