The OnGetText and OnSetText events, can be used to customize the output of a field. These two(2) events are extremely powerful: they allow you to use data-aware controls even when the representation of a field you want to display is different from the one Delphi will provide by default.

procedure TForm1.Table1ShipDateGetText

(Sender: TField;

var

        Text: string;

        DisplayText: boolean);

begin

   if Sender.IsNull then

        Text := '<undefined>'

   else

        Text := Sender.AsString;        

end;

procedure TForm1.Table1ShipDateSetText

(Sender: TField;

const Text: string);

begin

   if Text = '' then

        Sender.Clear

   else

        Sender.AsString := Text;

end;