Adding textbox and autocomplete extender

Question

Hi,
 
I wanted to use textbox and autocomplete extender in gridview. after entering in textbox corresponding letter series should come from database like google search. I am not getting what procedures to follow for adding textbox and autocomplete extender in gridview. i have done this without using gridview. Now i wanted to use in gridview. please can anybody help me regarding this?

Thanks in advance.