public ActionResult Edit(ProductCategoryManageEditViewModel model)
        {
            if (ModelState.IsValid)
            {
                var productCategory = new ProductCategory
                {
                    Id = model.Id,
                    Name = model.Name,
                    Description = model.Description,
                    UrlSlug = model.UrlSlug
                };

                db.Entry(productCategory).State = EntityState.Modified;
                db.SaveChanges();
                return RedirectToAction("Index");
            }
            return View(model);
        }
        // GET: ProductCategoryManage/Edit/5
        public ActionResult Edit(int? id)
        {
            if (id == null)
            {
                return new HttpStatusCodeResult(HttpStatusCode.BadRequest);
            }
            ProductCategory productCategory = db.ProductCategories.Find(id);
            if (productCategory == null)
            {
                return HttpNotFound();
            }

            var vm =new ProductCategoryManageEditViewModel{
                Id=productCategory.Id,
                Name=productCategory.Name,
                Description=productCategory.Description,
                UrlSlug=productCategory.UrlSlug
            };
            return View(vm);
        }