How to find the control in Gridview Footer row using C#

protected void gdvs_RowDataBound(object sender, GridViewRowEventArgs e)
        {
            if (e.Row.RowType == DataControlRowType.Footer)
            {
                Button btnDelete = (Button)e.Row.FindControl("btnDeleteRow");
                btnDelete.Visible = false;
            }

           
        }