StringGrid 编辑状态下如何垂直居中？

OnDrawCell 里的代码对编辑状态不起作用procedure TFrmCompanyEdit.StringGrid1DrawCell(Sender: TObject; ACol,
  ARow: Integer; Rect: TRect; State: TGridDrawState);
begin
  with Sender as TStringGrid do
  begin
    // do something
    Canvas.FillRect(Rect);
    DrawText(Canvas.Handle, PChar(Cells[ACol, ARow]), Length(Cells[ACol, ARow]), Rect, DT_CENTER or DT_SINGLELINE or DT_VCENTER);
  end;
end;