>Hi Nancy..
>
>I don't have very clear the topic of the buffering yet , as you will have imagined.
>What I was trying to do, is to validate the key in the moment in that the user was entering the data (that is to say in the Valid Event of the fields) and if he finds a registration with that key, it doesn't allow him
>to continue (like in the old FoxProw 2.6), but the record it is already created, so it always returns me .t. (when I look for the key)..
>
>
>Thanks...

You may not create a record. It's not mandatory at all. You can empty textbox.controlsource and let user to enter whatever he/she wants: it will not go to table until you will issue INSERT INTO (new record) or REPLACE (edit record).
BTW, it's better to use surrogate keys to provide uniqueness.