public int updateProduct(SanPham sp)
        {
            QuanLySanPhamDAO dao = new QuanLySanPhamDAO();

            return(dao.updateProduct(sp));
        }
        public int addProduct(SanPham sp)
        {
            QuanLySanPhamDAO dao = new QuanLySanPhamDAO();

            return(dao.addProduct(sp));
        }
        public int removeProduct(string maSP)
        {
            QuanLySanPhamDAO dao = new QuanLySanPhamDAO();

            return(dao.removeProduct(maSP));
        }
        public DataTable loadAllUnitProduct()
        {
            QuanLySanPhamDAO dao = new QuanLySanPhamDAO();

            return(dao.loadAllUnitProduct());
        }