public ActionResult Create(Product product)
        {
            Product prd = new Product();
            ProductCategory prdCat = new ProductCategory();
            ProductPicture picProd = new ProductPicture();
            product.ProductGuid = Guid.NewGuid();
            _productRepository.Add(product);
            prd = _productRepository.GetProductByGuid(product.ProductGuid);

            prdCat.CategoryID = product.CategoryID;
            prdCat.ProductID = prd.ID;
            if (product.CategoryID != 0)
            {
                _categoryRepository.InsertProductCategory(prdCat);
            }

            picProd.PictureID = product.PictureID;
            picProd.ProductID = prd.ID;
            picProd.DisplayOrder = 1;

            if (picProd.PictureID != 0)
            {
                _productRepository.InsertProductPicture(picProd);
            }

            return RedirectToAction("List");
        }
        public ActionResult Edit(Product product)
        {
            Product prd = new Product();
            ProductCategory prdCat = new ProductCategory();
            ProductPicture picProd = new ProductPicture();
            _productRepository.Update(product);

            prdCat.ProductID = product.ID;
            prdCat.CategoryID = product.CategoryID;

            if(product.CategoryID != 0)
            _categoryRepository.UpdateProductCategory(prdCat);

            picProd.PictureID = product.PictureID;
            picProd.ProductID = product.ID;
            if(product.PictureID != 0)
            _productRepository.UpdateProductPicture(picProd);

            return RedirectToAction("List");
        }