if (GridvView1.Rows.Count > 0)
{
GridViewRowCollection rc = GridvView1.Rows;
foreach (GridViewRow gRow in rc)
{
CheckBox cBox = (CheckBox)(gRow.FindControl("chkSelect"));
if (cBox.Checked == true)
{
//comparisions to be made &
//if u want to save any values then use some or
//static variables
}
}
}