Author: Tomas Rutkauskas

I'm trying to ensure that a TListBox is wide enough to hold the items in it. 
However, I see no method for determining if a scroll bar exists, and if so how wide 
it is.

Answer:

1   procedure TForm1.FormShow(Sender: TObject);
2   var
3     LBStyle: Longint;
4   begin
5     LBStyle := GetWindowLong(ListBox1.Handle, GWL_STYLE);
6     if (LBStyle and WS_VSCROLL) <> 0 then
7       ShowMessage(' ScrollBar visible, its width is ' + 
8   IntToStr(GetSystemMetrics(SM_CYVSCROLL))
9         + ' pixels ')
10    else
11      ShowMessage('ScrollBar not visible');
12  end;