Knowledge Base

BUG: DBGrid with Visible Property Set to False Becomes Visible

Article ID: 139971

Article Last Modified on 11/18/2003

Microsoft Visual Basic 4.0 Standard Edition
Microsoft Visual Basic 4.0 Professional Edition
Microsoft Visual Basic 4.0 Enterprise Edition

This article was previously published under Q139971

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

Start Visual Basic, or if it is already running, click New Project on the File menu.
In the toolbox, double-click the data control button to add a new data control to the project.

Modify the following properties of the data control:

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

In the toolbox, double-click DBGrid to add a DBGrid control to the form.
In the Properties window, change the DataSource property of the DBGrid control to Data1.
Change the DBGrid's Visible property to False.
Click and drag a single command button, named Command1 by default, onto the form.

Add the following code to the Command1_Click procedure:

       Private Sub Command1_Click()
          Data1.Refresh
       End Sub

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

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

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

On the Run menu, click Start or press F5 to start your application. The DBGrid control is not displayed.
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: kbbug KB139971