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Q192184: HOWTO: Add a Horizontal Scroll Bar to a Visual Basic ListBox

Article: Q192184
Product(s): Microsoft Visual Basic for Windows
Version(s): WINDOWS:4.0,5.0,6.0
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 Learning Edition for Windows, versions 5.0, 6.0 
- Microsoft Visual Basic Professional Edition for Windows, versions 5.0, 6.0 
- Microsoft Visual Basic Enterprise Edition for Windows, versions 5.0, 6.0 
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SUMMARY
=======

The normal ListBox that comes with Visual Basic for Windows does not have a
horizontal scroll bar. This can be a problem when the item in a ListBox extends
past the boundaries of the ListBox. To add a horizontal scroll bar to the
control, you can call the Windows API SendMessage function with the
LB_SETHORIZONTALEXTENT constant.

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

This message sets the width in pixels by which a ListBox can scroll
horizontally. If the width of the ListBox is smaller than this value, a
horizontal scroll bar will be added to allow horizontally scrolling items in the
ListBox.

Step-by-Step Example
--------------------

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

2. Add a CommandButton and a ListBox to Form1.

3. Paste the following code into the general declaration section of Form1:

        Option Explicit

        Private Declare Function SendMessageByNum Lib "user32" _
          Alias "SendMessageA" (ByVal hwnd As Long, ByVal _
          wMsg As Long, ByVal wParam As Long, ByVal lParam As Long) As Long
        Const LB_SETHORIZONTALEXTENT = &H194

        Private Sub Command1_Click()
           Dim s As String
           Static x As Long
           s = InputBox("Please enter any text", "List scroll", _
             "this is a simple scrollbar sample for demonstration purposes")
           List1.AddItem s
           If x < TextWidth(s & "  ") Then
              x = TextWidth(s & "  ")
             If ScaleMode = vbTwips Then _
                 x = x / Screen.TwipsPerPixelX  ' if twips change to pixels
             SendMessageByNum List1.hwnd, LB_SETHORIZONTALEXTENT, x, 0
           End If
        End Sub

4. Run the project and click on Command1. You will be prompted to enter a text
  string to be added to the ListBox. Each time you enter a string, the code
  checks to see if it is longer than the previous longest string and will
  adjust the scroll bar as necessary.

REFERENCES
==========

For information on performing this task in 16-bit versions of Visual Basic,
please see the following article in the Microsoft Knowledge Base:

  Q80190 : HOWTO: Add a Horizontal Scroll Bar to Visual Basic ListBox

Additional query words: kbDSupport kbDSD kbVBp kbVBp400 kbVBp500 kbVBp600 kbCtrl kbAPI

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Keywords          : kbGrpDSVB 
Technology        : kbVBSearch kbAudDeveloper kbZNotKeyword6 kbZNotKeyword2 kbVB500Search kbVB600Search kbVBA500 kbVBA600 kbVB500 kbVB600
Version           : WINDOWS:4.0,5.0,6.0
Issue type        : kbhowto

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