/// <summary>
 /// Bài 34
 /// </summary>
 /// <param name="id"></param>
 /// <returns></returns>
 public ActionResult Detail(long id)
 {
     var productDao = new ProductDao();
     var product = productDao.ViewDetail(id);
     if (product.CategoryID != null)
         ViewBag.Category = new ProductCategoryDao().ViewDetail(product.CategoryID.Value);
     ViewBag.RelatedProducts = productDao.ListRelatedProducts(id, 4);
     return View(product);
 }