dbgrid怎样实现指针指向的行高亮！

procedure Tfrm_Main.Grid_DataDrawCell(Sender: TObject; ACol, ARow: Integer;
  Rect: TRect; State: TGridDrawState);
var
  aRect:TRect ;
begin
   with TStringGrid(Sender) do
    begin

      Canvas.Brush.Color := clGreen ;
      Canvas.FillRect(Rect);

      ARect := Rect;
      DrawText(Canvas.Handle, PChar(Cells[ACol, ARow]), -1, ARECT,
        DT_SINGLELINE or DT_VCENTER);

    end;
end;