Page goes refreshing when click on edit event in gridiview?

Question

                                                                                                                                                                           In the above image i have two tabs 1st one add investment and 2 one is invest data in invest data i used gridview to bind data from database but when click on edit button it goes page refreshing and going to the 1st tab i.e add investment, Here event is worikng but i don't want page refresh i used updatepanel also but it's not working