Author: William Gerbert

Enabling a horizontal scrollbar in a TListBox

Answer:

Solve 1:

There is no such property in TListBox. To force a listbox to have horizontal 
scrollbars, use the message LB_SETHORIZONTALEXTENT. 

1   // e.g. in FormCreate(..)
2   begin
3     ListBox1.Width := 300;
4     // listbox can be scrolled by 100 pixels horizontally now:
5     SendMessage(ListBox1.Handle, LB_SETHORIZONTALEXTENT, 400, 0);
6   end;



Solve 2:

7   MaxWidth := 0;
8   for i := 0 to ListBox1.Items.Count - 1 do
9     if MaxWidth < ListBox1.Canvas.TextWidth(ListBox1.Items.Strings[i]) then
10      MaxWidth := ListBox1.Canvas.TextWidth(ListBox1.Items.Strings[i]);
11  SendMessage(ListBox1.Handle, LB_SETHORIZONTALEXTENT, MaxWidth + 100, 0);

It uses the Messages .dcu.