[VBnet List API] SetWindowLong: Right-Align List Box Data and/or the Scrollbar


	Visual Basic List API SetWindowLong: Right-Align List Box Data and/or the Scrollbar

Posted:	Saturday November 03, 2001
Updated:	Monday December 26, 2011

Applies to:	VB4-32, VB5, VB6
Developed with:	VB6, Windows XP
OS restrictions:	None
Author:	Harald Genauck, VBnet - Randy Birch

Related:	VBnet CoolTabs GetTextExtentPoint32: Right-Align List Box Data SetWindowLong: Right-Align List Box Data and/or the Scrollbar SetWindowLong: Right-Align List Contents in a Combo SendMessage: Align Text Box Contents Using Tabstops SendMessage: Align List Box Contents Using Tabstops WM_LBUTTONDOWN: Substitute a Tabbed List for a Combo's Dropdown List WM_LBUTTONDOWN: Substitute a ListView for a Combo's Dropdown List

Prerequisites

None.

The newsgroup request for code to create a right-aligned column of numbers in a list box was one of those fun projects in our mvp VB newsgroup that ended up generating quite a few methods to accomplish this. This routine, based on the method provided by Harald M. Genauck, forces the listbox to display its contents right-aligned by toggling the listbox alignment extended style bit. It's certainly the simplest method we encountered. I've added an additional method to completely render UI specs and conformance useless by moving the vertical scrollbar to the left. Either of these options can be set independently, providing complete flexibility.

BAS Module Code

None.

Form Code

To the form containing a list (List1) and two check boxes (Check1, Check2), add the following code:

Option Explicit

''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''
' Copyright ©1996-2011 VBnet/Randy Birch, All Rights Reserved.
' Some pages may also contain other copyrights by the author.
''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''
' Distribution: You can freely use this code in your own
'               applications, but you may not reproduce 
'               or publish this code on any web site,
'               online service, or distribute as source 
'               on any media without express permission.
''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''''

Private Const GWL_EXSTYLE As Long = (-20)
Private Const WS_EX_RIGHT As Long = &H1000
Private Const WS_EX_LEFTSCROLLBAR As Long = &H4000

Private Declare Function GetWindowLong Lib "user32" _
   Alias "GetWindowLongA" _
  (ByVal hwnd As Long, _
   ByVal nIndex As Long) As Long

Private Declare Function SetWindowLong Lib "user32" _
   Alias "SetWindowLongA" _
  (ByVal hwnd As Long, _
   ByVal nIndex As Long, _
   ByVal dwNewLong As Long) As Long

Private Enum AlignConstants
   alignLeft = 0
   alignRight = 1
End Enum

   

Private Sub Form_Load()

   Dim x As Long
   
   For x = 0 To Screen.FontCount - 1
      List1.AddItem Screen.Fonts(x)
   Next

   Check1.Caption = "Align Scrollbar to Left"
   Check2.Caption = "Align Text to Right"
   
End Sub


Private Sub Check1_Click()
   
  'Since the values of the alignment Enum
  'correspond to the two values of a checkbox, 
  'the checkbox value property can be used 
  'directly as the alignment style parameter.
   ListScrollAlign List1, Check1.Value
   
End Sub

Private Sub Check2_Click()
  
   ListBoxAlign List1, Check2.Value

End Sub


Private Sub ListBoxAlign(lb As ListBox, _
                         Optional ByVal Align As AlignConstants = alignLeft)

   Dim nStyle As Long

   With lb
      
      nStyle = GetWindowLong(.hwnd, GWL_EXSTYLE)
        
      Select Case Align
         Case alignRight:
            nStyle = nStyle Or WS_EX_RIGHT
         Case alignLeft:
            nStyle = nStyle And Not WS_EX_RIGHT
      End Select
      
      SetWindowLong .hwnd, GWL_EXSTYLE, nStyle
    
   End With
    
End Sub


Private Sub ListScrollAlign(lb As ListBox, _
                            Optional ByVal Align As AlignConstants = alignRight)

   Dim nStyle As Long
   
   With lb
      
      nStyle = GetWindowLong(.hwnd, GWL_EXSTYLE)
        
      Select Case Align
         Case alignRight:
            nStyle = nStyle Or WS_EX_LEFTSCROLLBAR
         Case alignLeft:
            nStyle = nStyle And Not WS_EX_LEFTSCROLLBAR
      End Select
      
      SetWindowLong .hwnd, GWL_EXSTYLE, nStyle
    
   End With
   
End Sub

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