how to access gridview column values into another function ?

Question

i have a gridview named GridView1 which has 6 columns 1st and 6th is a buttonfield.

on a button submit click i binded gridview1 now i have another function for which i need Gridview1 column data. 

 

i tried using

lblname.text= GridView1.SelectedRow.Cell[2].text

but when it comes to this line it shows an error:

object reference not set to an instance of an object