Author: Tomas Rutkauskas

I have a TListBox with style lbOwnerDrawVariable. I want to draw some text indented 
10 pixels from the left (this is no problem). However, I also want it so the 
highlighting color and focus rectangle are indented as well (so the 10 pixel margin 
is completely blank, no matter what items are selected). I can't seem to do this 
... the focus rectangle always seems to extend all the way to the left. How do I 
get around this?

Answer:

The problem is that the control as coded draws the focus rectangle after your owner 
drawing code has completed. To override that you have to make a new control 
descending from TListbox (or TCustomlistbox) and give it a handler for the 
CN_DRAWITEM message. Here you need to duplicate what the TCustomlistbox.CNDrawItem 
method does:
1   
2   procedure TMyListBox.CNDrawItem(var message: TWMDrawItem);
3   var
4     State: TOwnerDrawState;
5   begin
6     with message.DrawItemStruct^ do
7     begin
8       State := TOwnerDrawState(LongRec(itemState).Lo);
9       Canvas.Handle := hDC;
10      Canvas.Font := Font;
11      Canvas.Brush := Brush;
12      if (Integer(itemID) >= 0) and (odSelected in State) then
13      begin
14        Canvas.Brush.Color := clHighlight;
15        Canvas.Font.Color := clHighlightText
16      end;
17      if Integer(itemID) >= 0 then
18        DrawItem(itemID, rcItem, State)
19      else
20        Canvas.FillRect(rcItem);
21      if odFocused in State then
22      begin
23        Inc(rcItem.left, 10); {this is the change}
24        DrawFocusRect(hDC, rcItem);
25      end;
26      Canvas.Handle := 0;
27    end;
28  end;