public JsonResult GetSanPhamPT(int pageIndex, int pageSize, string productName)
        {
            if (Session["maloai"] == null)
            {
                Session.Add("maloai", "Rau");
            }
            SanPhamList spl = qlsp.LaySanPhamPT(Session["maloai"].ToString(), pageIndex, pageSize, productName);

            return(Json(spl, JsonRequestBehavior.AllowGet));
        }
        public JsonResult GetSanPhamPT(int pageIndex, int pageSize)
        {
            SanPhamList spl = qlsp.LaySanPhamPT(pageIndex, pageSize);

            return(Json(spl, JsonRequestBehavior.AllowGet));
        }