Q201577: BUG: TreeView Scroll Bar Does Not Disappear When Scroll = False

Article: Q201577
Product(s): Microsoft Visual Basic for Windows
Version(s): 6.0
Operating System(s): 
Keyword(s): kbAPI kbCmnCtrls kbCtrl kbSDKWin32 kbTreeView kbVBp kbGrpDSVB kbDSupport
Last Modified: 24-JUN-2001

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The information in this article applies to:

- Microsoft Visual Basic Enterprise Edition for Windows, version 6.0, used with:
   - Microsoft Windows 95 
   - Microsoft Windows 98 
   - Microsoft Windows Millennium Edition 
- Microsoft Visual Basic Professional Edition for Windows, version 6.0, used with:
   - Microsoft Windows 95 
   - Microsoft Windows 98 
   - Microsoft Windows Millennium Edition 
- Microsoft Visual Basic Learning Edition for Windows, version 6.0, used with:
   - Microsoft Windows 95 
   - Microsoft Windows 98 
   - Microsoft Windows Millennium Edition 
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SYMPTOMS
========

If you set the Scroll property of the TreeView control from Microsoft Windows
Common Controls (Mscomctl.ocx) to False at run time, the scroll bar does not
disappear as expected.

RESOLUTION
==========

To work around this problem, call the ShowScrollBar function instead of using
the Scroll property. The following example demonstrates how to use the
ShowScrollBar function:

1. Open a new Standard EXE project in Visual Basic. Form1 is created by default.

2. On the Project menu, click Components, select the "Microsoft Windows Common
  Controls 6.0" check box, and then click OK.

3. Add a TreeView control (TreeView1) and a CheckBox control (Check1) to Form1.

4. Add the following code to the General Declarations section of Form1:

  Option Explicit

  Private Const SB_VERT = 1

  Private Declare Function ShowScrollBar Lib "user32" _
      (ByVal hWnd As Long, ByVal wBar As Long, ByVal bShow As Long) As Long

  Private Sub Check1_Click()
  ' The reference to CBool is not required but is used to enhance clarity.
      Call ShowScrollBar(TreeView1.hWnd, SB_VERT, CBool(Check1.Value))
  End Sub

  Private Sub Form_Load()
      Dim i As Integer
      For i = 1 To 20
          TreeView1.Nodes.Add , , , "Item " & i
      Next i
      Check1.Caption = "Show Scroll Bar"
      Check1.Value = vbChecked
  End Sub

5. Run the code, and notice that a vertical scroll bar appears on the TreeView
  control.

6. Click Show Scroll Bar, and notice that the scroll bar disappears. Click Show
  Scroll Bar again, and notice that the scroll bar re-appears.

STATUS
======

Microsoft has confirmed this to be a problem in the TreeView control from
Microsoft Windows Common Controls (Mscomctl.ocx) under Windows 95, Windows 98,
and Windows Millennium Edition.

NOTE: This problem does not occur under Windows NT 4.0 and Windows 2000.

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

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

NOTE: You must perform these steps on a computer that is running Windows 95,
Windows 98, or Windows Millennium Edition (Me).

1. Open a new Standard EXE project in Visual Basic. Form1 is created by default.

2. On the Project menu, click Components. In the Components dialog box, select
  the "Microsoft Windows Common Controls 6.0" check box, and then click OK.

3. Add a TreeView control (TreeView1) and a CommandButton control (Command1) to
  Form1.

4. Add the following code to the General Declarations section of Form1:

  Option Explicit

  Private Sub Command1_Click()
      TreeView1.Scroll = False
  End Sub

  Private Sub Form_Load()
      Dim i As Integer
      For i = 1 To 20
          TreeView1.Nodes.Add , , , "Item " & i
      Next i
      Command1.Caption = "Hide Scroll Bar"
  End Sub

5. Run the code, and notice that a vertical scroll bar appears on the TreeView
  control.

6. Click Hide Scroll Bar, and notice that the scroll bar is still displayed.

REFERENCES
==========

For additional information, click the article number below to view the article
in the Microsoft Knowledge Base:

  Q189249 HOWTO: Determine Which 32-Bit Windows Version Is Being Used

Additional query words:

======================================================================
Keywords          : kbAPI kbCmnCtrls kbCtrl kbSDKWin32 kbTreeView kbVBp kbGrpDSVB kbDSupport 
Technology        : kbVBSearch kbAudDeveloper kbZNotKeyword6 kbZNotKeyword2
Version           : :6.0
Issue type        : kbbug
Solution Type     : kbnofix

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