how to get the checkbox selected value from gridview

Question

 

 

  In gridview as follows

Select               studentid

checkbox                  2
checkbox                  4
checkbox                  5


i want to add gridview checkbox selected row into listbox.
i have listbox as follows

In listbox selected checkbox data to be added in the listbox
Suppose user select firstrow and secondrow using checkbox means that gridview selected rows to be added in the listbox.

In listbox i want output as follows
studentid
2
4

for that how can i do in asp.net using c#.