procedure TForm1.ListBox1DrawItem(Control: TWinControl; Index: Integer;
  Rect: TRect; State: TOwnerDrawState);
  var LB: TListBox;
begin
  LB := (control as TListBox);
    case Index of
      1: begin
         LB.Canvas.Brush.Color := clRed;
         LB.Canvas.Font.Color := clBlack;
         LB.Canvas.Pen.Color := clWhite;
         end;
      2: begin
         LB.Canvas.Brush.Color := clYellow;
         LB.Canvas.Font.Color := clBlack;
         LB.Canvas.Pen.Color := clWhite;
         end;
[...]
      else
        begin
        LB.Canvas.Brush.Color := clWhite;
        LB.Canvas.Font.Color := clBlack;
        end;
    end;
    LB.Canvas.Rectangle(Rect);
    LB.Canvas.TextOut(Rect.Left + 1, Rect.Top + 1, LB.Items[Index]);
end;