计算GridView中每列的总值并在页脚中显示它们

从周日到周六，我的Gridview中有7列。我需要在每一列中添加值，并将它们显示在页脚上。我试着做一个专栏，但不能做每一个专栏。

   int total=0;
    protected void gvEmployeeTimeSheet_RowDataBound(object sender, GridViewRowEventArgs e)
    {          
        if (e.Row.RowType == DataControlRowType.DataRow)
        {  
            Label lblsaturday = (Label)e.Row.FindControl("lblSaturday");
            int qty = Int32.Parse(lblsaturday.Text);
             total = total + qty;
        }
        if (e.Row.RowType == DataControlRowType.Footer)
        {
            Label lblTotalqty = (Label)e.Row.FindControl("lblFootersaturday");
            lblTotalqty.Text = total.ToString();
        }
    }