if (GridView1.Rows.Count > 0)
    {
        
        for(K=1;k>GridView1.Columns.Count-1;k++)
        {
         decimal amount = 0;
         foreach (GridViewRow row in GridView1.Rows)
         {
            amount += Decimal.Parse(row.Cells[K].Text, System.Globalization.NumberStyles.Any);
         }
         GridView1.FooterRow.Cells[0].Text="amount";
         GridView1.FooterRow.Cells[K].Text = string.Format("{0:F0}", amount);
        }
    }