How to get data from EditTextField to UserDataSource without lose focus

Hi,

I'm trying to rebuild a ChooseFromList form like that for Business Partners.

There is an edit text field where you can enter a cardcode. By every keyDown it checks for matches in the matrix of all business partners below and autoselects the first matching or the first in list if none is matching.

Now my experience is, the text in the editTextField is only written to UDS if it loses focus. But thats not what i want. Can i force the data to be written to the datasource? Or have i to force my editTextField to lose focus and get it new after every keydown? How may this work?

Can you please help me?

Thx