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Q139971: BUG:DBGrid with Visible Property Set to False Becomes Visible

Article: Q139971
Product(s): Microsoft Visual Basic for Windows
Version(s): 4.0
Operating System(s): 
Keyword(s): kbbuglist
Last Modified: 02-NOV-2001

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The information in this article applies to:

- Microsoft Visual Basic Standard Edition for Windows, version 4.0 
- Microsoft Visual Basic Professional Edition for Windows, version 4.0 
- Microsoft Visual Basic Enterprise Edition for Windows, version 4.0 
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SYMPTOMS
========

A DBGrid that has its Visible property set to False does not remain invisible
when the data control referenced in its DataSource property is refreshed (via
the Refresh method) or has its current record changed.

CAUSE
=====

As a side effect of these methods, a message to repaint is sent to a data bound
grid. In this case, the problem is that the DBGrid control does not check its
Visible property to see if it is all right to draw itself on the form, it just
goes ahead and does it.

WORKAROUND
==========

Executing the following line of code

      <DBGrid Name>.Visible = False

causes another Paint message to be sent to the DBGrid control, but this time the
grid behaves correctly and hides itself. The workaround is to place this line of
code (shown above) in the Reposition event of the data control. Whenever a data
control executes a Refresh method, or any of the Move methods, the Reposition
event is called, and this line of code causes the correct painting to occur.


Another workaround is to move the DBGrid control off of the visible section of
the form when it should not be seen. You can use a line of code such as the
following:

    DBGrid1.Move -5000, -5000

To make the DBGrid visible again, move it back to the correct location on the
form.


STATUS
======

Microsoft has confirmed this to be a bug in the Microsoft products listed at the
beginning of the article. 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. Start Visual Basic, or if it is already running, click New Project on the
  File menu.

2. In the toolbox, double-click the data control button to add a new data
  control to the project.

3. Modify the following properties of the data control:

        DatabaseName: <path to your VB directory>\biblio.mdb
        RecordSource: Authors

4. In the toolbox, double-click DBGrid to add a DBGrid control to the form.

5. In the Properties window, change the DataSource property of the DBGrid
  control to Data1.

6. Change the DBGrid's Visible property to False.

7. Click and drag a single command button, named Command1 by default, onto the
  form.

8. Add the following code to the Command1_Click procedure:

         Private Sub Command1_Click()
            Data1.Refresh
         End Sub

9. On the Run menu, click Start or press the F5 key to start your application.
  The DBGrid control is not displayed as expected.

10. Click the command button to send a Refresh to the data control. This causes
  the DBGrid control to be drawn on the form, despite the fact that its
  Visible property is false.

11. Stop the application, then add the following code to the Data1_Reposition
  procedure:

        Private Sub Data1_Reposition()
           DBGrid1.Visible = False
        End Sub

12. On the Run menu, click Start or press F5 to start your application. The
  DBGrid control is not displayed.

13. Click the command button to send a Refresh to the data control. The DBGrid
  control is not displayed, which is the desired behavior.

Additional query words: 4.00 vb4win vb4all buglist4.00

======================================================================
Keywords          :  kbbuglist
Technology        : kbVBSearch kbAudDeveloper kbZNotKeyword6 kbZNotKeyword2 kbVB400Search kbVB400
Version           : :4.0
Issue type        : kbbug

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