ComboBox: "Pfeil-" Button verändern

[Bummi]

nur als Einstieg, was Du mit dem Canvas machst überlasse ich Dir ...

Delphi-Quellcode:

type
  TComboBox=Class(StdCtrls.TComboBox)
  Protected
    procedure WMPaint(var Message: TWMPaint); message WM_PAINT;
  End;
  TForm2 = class(TForm)
....
....
{ ComboBox }

procedure TComboBox.WMPaint(var Message: TWMPaint);
var
 r:Trect;
 c:Tcanvas;
begin
  inherited;
        c:=Tcanvas.Create;
        c.Handle := GetDC(handle);
        R := ClientRect;
        R.Left := R.Right - GetSystemMetrics(SM_CXHTHUMB);
        if Style <> csSimple then
        Canvas.FillRect(r);
          if DroppedDown then
            c.TextOut(r.left,r.top,'D')
         else
            c.TextOut(r.left,r.top,'U');

        ReleaseDC(handle,c.Handle);
        c.Free;
end;