gridView cummulative total on level break

if (e.Row.Cells[1].Text!=shiptp122)
{
RunTot = 0;
}
RunTot += (Convert.ToInt32(e.Row.Cells[2].Text));
e.Row.Cells[3].Text = Convert.ToString(RunTot);
shiptp122 = e.Row.Cells[1].Text;

www.svdeals.com cummulative total