求高手指点分行显示GridEh背景颜色的问题

procedure TRejectForm.DBGridEh1DrawColumnCell(Sender: TObject;
  const Rect: TRect; DataCol: Integer; Column: TColumnEh;
  State: TGridDrawState);
begin
  case Datainout.QRClientDataSet.FieldByName('flag').AsBoolean=True of
    True :  DBGridEh1.Canvas.brush.color:=clwindow;
    False : DBGridEh1.canvas.Brush.color:=clSkyBlue;
  end;
  if((State=[gdselected]) or(State=[gdselected,gdFocused])) then
   DBGridEh1.Canvas.brush.color:=clactivecaption;
   DBGridEh1.canvas.pen.mode:=pmmask;
  DBGridEh1.DefaultDrawColumnCell(rect,datacol,column,State);
end;

老是提示DBGridEh1.DefaultDrawColumnCell(rect,datacol,column,State);出错
错误代码：incompatible types

求高手指点，为何出错啊