datagridview checkbox column

Question

Hi,
In a winform I have a datagridview and in that dgv I have created a checkbox column. Now when I run this form it shows that checkbox column. Now my question is how to identify whether a particular row's checkbox is checked or not? Because after checking I am going to assign some value to an integer variable. That is if a particular row's checkbox is checked then I am going to assign value 1 to that integer variable else the value zero.
Thanks