PRB: Cannot Set TabStops in ListBox Using SendMessage API

• Microsoft Visual Basic Learning, Professional, and Enterprise Editions for Windows, versions 5.0, 6.0

SYMPTOMS

When you use the SendMessage API and the LB_SETTABSTOPS message to define custom TabStops within a ListBox control to give the appearance of multiple columns, there is no effect on a ListBox control whose Style property is set to "1 - Checkbox."

CAUSE

To set the columns in the ListBox, send the ListBox control a LB_SETTABSTOPS message along with information to define the TabStops. A list box must be created with the LBS_USETABSTOPS style to respond to this message. The Visual Basic ListBox with a style set to "1 - Checkbox" is not created with the LBS_USETABSTOPS style. Therefore, the LB_SETTABSTOPS message has no effect on the ListBox control.

RESOLUTION

To set custom TabStops within the standard Visual Basic ListBox control, you must set the style setting to "0 [ASCII 150] Standard." Alternatives include using controls provided by third-party vendors, or using the Microsoft Grid or ListView controls to obtain the look and functionality you desire.

STATUS

This behavior is by design.

MORE INFORMATION

Steps to Reproduce Behavior

1. Create a new Standard EXE project.



2. Add a command button to Form1.



3. Add a ListBox control to Form1.



4. Paste the following code into Form1's code window:

   
         Option Explicit
   
         Private Declare Function SendMessage Lib "User32" _
                                  Alias "SendMessageA" _
                                  (ByVal hWnd As Long, _
                                  ByVal wMsg As Long, _
                                  ByVal wParam As Long, _
                                  lParam As Any) As Long
         Private Const LB_SETTABSTOPS = &H192
   
         Private Sub Command1_Click()
             Dim ListBoxTabs(2) As Long
             Dim result As Long
   
             'Set the tab stop points.
             ListBoxTabs(1) = 75
             ListBoxTabs(2) = 200
   
             'Send LB_SETTABSTOPS message to ListBox.
             result = SendMessage(List1.hWnd, LB_SETTABSTOPS, _
                                  UBound(ListBoxTabs) + 1, _
                                  ListBoxTabs(1))
   
             'Refresh the ListBox control.
             List1.Refresh
         End Sub
   
         Private Sub Form_Load()
             'Add a few items to the ListBox.
             List1.AddItem "January Sales" & vbTab & _
                           "February Sales" & vbTab & _
                           "March Sales"
             List1.AddItem "50" & vbTab & _
                           "500" & vbTab & _
                           "5000"
         End Sub
    




5. Save and run the project.



6. Click Command1.
   
   RESULT: Two TabStops are set in the ListBox control. The first is 75 twips and the second is 200 twips.



7. Stop the application.



8. Set the Style property of the ListBox control to "1 [ASCII 150] Checkbox."



9. Repeat steps 5 and 6.
   
   RESULT: The TabStops do not affect the ListBox control.

Additional query words: list box check box kbVBp500 kbVBp600 kbControl kbWin32SDK kbAPI
kbVBp kbdsd kbDSupport

Keywords : kbGrpVB
Version :
Platform : WINDOWS
Issue type : kbprb