Dynamically bind data in DropDownList in GridView edit update delete in ASP.Net

i  cretaed  3 category table. categry1,categry2,categry3. product table.

and then use of gried view add ,edit ,update ,delete  product . in product table.

in griedview retrive data from product table . i select categry from dropdownlist in griedview categry1,categry2,categry3   and save  update  dropdown list category value dynamically  in product table.  not define value static  in source code. 

when select category 1 change  on selected index change categary 2 or 3.

sir you have demo help me...    in my code  i used text box to ediit update delete. but here i will use dropdownlist.