public ActionResult EditProduct(ChiTietSanPhamViewModel model)
 {
     if (!Roles.IsUserInRole("admin"))
     {
         return RedirectToAction("Index", "Admin");
     }
     else
     {
         bool thanhCong = SanPhamBLL.SuaThongTinSanPham(model.SanPham);
         if (thanhCong)
         {
             return Json(new { Flag = "Success" });
         }
         else
         {
             return Json(new { Flag = "Unsuccess" });
         }
     }
 }
        //
        public ActionResult EditProduct(int id)
        {
            if (!Roles.IsUserInRole("admin"))
            {
                return RedirectToAction("Index", "Admin");
            }
            else
            {
                SanPham sanpham = SanPhamBLL.LayThongTinSanPham(id);
                List<TinhTrang> danhSachTinhTrang = TinhTrangBLL.LayDanhSachTinhTrang();
                ChiTietSanPhamViewModel viewModel = new ChiTietSanPhamViewModel()
                {
                    SanPham = sanpham,
                    CacTinhTrang = danhSachTinhTrang
                };

                return View(viewModel);
            }
        }