I'm not sure about the property to trigger a refresh, however for
your code snippet"

> Is this line
>
> iboquery.unprepare;
> iboquery.parambyname('code').AsString:=edit_1.text;
> iboquery.open;
>
> better than this line
>
> iboquery.close;
> iboquery.parambyname('code').AsString:=edit_1.text;
> iboquery.open;
>

I would be using Close/Open instead of Unprepare/Open... because
closing would keep the query prepared. In some of the queries I use
it can take 1/2 second or more to prepare, which can be annoying for
an interactive application.