Uso del gettext settext de un tfield

delphi_tfield.pas

procedure TForm1.Table1CategoryGetText(Sender: TField;
var Text: String; DisplayText: Boolean);
begin
case Sender.AsInteger of
1: Text := 'Electrical';
2: Text := 'Agricultural';
else
Text := '[Error]';
end;
end;

procedure TForm1.Table1CategorySetText(Sender: TField;
const Text: String);
begin
if Text = 'Electrical'then
Sender.Value := 1
else if Text = 'Agricultural' then
Sender.Value := 2
else
raise Exception.Create ('Error in Category field conversion');
end;

end.