foreach in gridview for the first 10 rows in pagesize=20

Question

i want to foreach in a gridview for first 10 the rows in a gidview but ,total coloum is 20.  in 1st page 10 and 2nd page  10...if  CheckBox check all only select first 10 rows .

foreach (GridViewRow row in gvStatus.Rows)

{

            CheckBox Check = (CheckBox)row.FindControl("ChkSelect"); 

             if (Check.Checked)

               {

                } 

}