asp.net gridview

Question

i have three method 

 

i have to call load event

 

when i click the button all the three method was called

 

i get the file in fileupload using button click event.and store file in session and call the all the method.but gridview not refsh .previous datasotre in gridivew

how to refersh the gridview in each time   get the file click the button  .