如何在丰富的编辑(Delphi)中左/右对齐行？

procedure TForm1.StringGrid1DrawCell(Sender: TObject; ACol, ARow: Integer;
  Rect: TRect; State: TGridDrawState);
var
  S: string;
begin
  if (ACol = 0) and (ARow > 0) then
  begin
    S := StringGrid1.Cells[ACol, ARow];
    StringGrid1.Canvas.FillRect(Rect);
    DrawText(StringGrid1.Canvas.Handle, PChar(S), Length(S), Rect,
      DT_LEFT or DT_VCENTER or DT_SINGLELINE);
  end;
end;