Delphi - 绘制到字符串网格中选定单元格的画布 - 可能吗？

procedure TForm1.StringGrid1DrawCell(Sender: TObject; ACol, ARow: Integer;
  Rect: TRect; State: TGridDrawState);
var
  Canvas: TCanvas;
  Text: string;
begin
  Canvas := TStringGrid(Sender).Canvas;
  Text := TStringGrid(Sender).Cells[ACol, ARow];

  if (ACol = TStringGrid(Sender).Col) and (ARow = TStringGrid(Sender).Row) then
  begin
    Canvas.Brush.Color := clYellow;
    Canvas.Font.Color := clBlue;
  end
  else
  begin
    Canvas.Brush.Color := clWhite;
    Canvas.Font.Color := clBlack;
  end;

  Canvas.FillRect(Rect);
  Canvas.TextRect(Rect, Rect.Left + 2, Rect.Top + 2, Text);
end;