Q149278: FIX: TreeView.Visible = False at Design-Time Causes Problems

Article: Q149278
Product(s): Microsoft Visual Basic for Windows
Version(s): 
Operating System(s): 
Keyword(s): kbGrpDSVB
Last Modified: 11-JAN-2001

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The information in this article applies to:

- Microsoft Visual Basic Standard Edition, 32-bit, for Windows, version 4.0 
- Microsoft Visual Basic Professional Edition, 32-bit, for Windows, version 4.0 
- Microsoft Visual Basic Enterprise Edition, 32-bit, for Windows, version 4.0 
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SYMPTOMS
========

After setting the Visible property of a TreeView control to False at design
time, odd behavior can be exhibited at run time. The reproduction sample at the
end of this article shows two examples. This behavior can range from the
Nodes.Count property returning incorrect values to all or some nodes not being
displayed, and even to GPFs in some cases.

RESOLUTION
==========

The work around for this problem is to not set the Visible property to False at
design time. If a TreeView control needs to be invisible when a form is shown,
the Visible property should be toggled in code before the form with the TreeView
is shown. This can easily be done in the Form_Load event of the TreeView laden
form with this line of code:

     TreeView1.Visible = False

STATUS
======

Microsoft has confirmed this to be a bug in the Microsoft products listed at the
beginning of this article. This bug has been fixed in Visual Basic 6.0.

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

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

1. Start Visual Basic 4.0. Form1 is created by default.

2. Add a single TreeView control and two command buttons to Form1.

3. Set this property of TreeView1:

  Visible: False

4. Add this code to Form1:

     Private Sub Form_Load()
        Dim nodX As Node  ' Create a tree.
        Set nodX = TreeView1.Nodes.Add(,,"r", "Root")
        Set nodX = TreeView1.Nodes.Add(,,"p", "Parent")
     End Sub

     Private Sub Command1_Click()
        TreeView1.Visible = True
        Debug.Print TreeView1.Nodes.Count
     End Sub

     Private Sub Command2_Click()
        TreeView1.Nodes.Clear
        Debug.Print TreeView1.Nodes.Count
     End Sub

5. Press F5 or select Start from the Run menu to start the application. Press
  the first command button--although the count property will say two, no nodes
  will be visible in the control. To demonstrate another oddity, stop and
  restart and then press Command2. The Clear method should have removed all
  nodes, but the Count property still returns 2.

Additional query words: kbVBp400bug kbVBp600fix kbVBp kbdsd kbDSupport kbControl

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Keywords          : kbGrpDSVB 
Technology        : kbVBSearch kbAudDeveloper kbVB400Search kbVB400
Issue type        : kbbug
Solution Type     : kbfix

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