Not too sure if I understand you correctly here, I am assuming English is not your first language?
If I understand correctly, you want to populate fields on a Web Form with data from a database
without clicking a button to do so?
I think what you need to remember here is that the Web is stateless. There is no "Form" in the same way that it is loaded into memory in a Windows appliation, its simply "faked" by using the ViewState & StateBag to store controls values. In which case a PostBack is always required.
I think what you are trying to achieve can be done via [possibly extensive] use of AJAX, but I would recommend waiting for the more experienced web guys to respond.
In the mean time, can you confirm if my assumption is correct?
Rob
http://cantgrokwontgrok.blogspot.com