public ActionResult Products_Read([DataSourceRequest]DataSourceRequest request, int categoryId)
 {
     using (var northwind = new NorthwindEntities())
     {
         IQueryable<Product> products = northwind.Products.Where(product => product.CategoryID == categoryId);
         // Flatten the Product to avoid circular references during JSON serialization
         DataSourceResult result = products.ToDataSourceResult(request, product => new
         {
             product.ProductID,
             product.ProductName
         });
         return Json(result);
     }
 }
 public ActionResult Categories_Read([DataSourceRequest]DataSourceRequest request)
 {
     using (var northwind = new NorthwindEntities())
     {
         IQueryable<Category> categories = northwind.Categories;
         // Flatten the Category to avoid circular references during JSON serialization
         DataSourceResult result = categories.ToDataSourceResult(request, category => new
         {
             category.CategoryID,
             category.CategoryName
         });
         return Json(result);
     }
 }