从TescoLabsApi接收产品详细信息时，我的MVC ShoppingCart应用程序中的AddtoCart方法返回Null：

Question

当我从TescoLabs Api获取产品信息时，当我调用AddtoCart方法时，我的方法返回null：

下面的My MakeRequest方法显示此屏幕 ：

public async Task<ActionResult> MakeRequest(string q)
{
    System.Net.ServicePointManager.SecurityProtocol |= SecurityProtocolType.Tls12;

    var client = new HttpClient();
    client.DefaultRequestHeaders.Add("Ocp-Apim-Subscription-Key", "api key ");

    var uri = string.Format("https://dev.tescolabs.com/grocery/products/?query={0}&offset={1}&limit={2}", q, 0, 100);

    var response = await client.GetAsync(uri);
    string body = await response.Content.ReadAsStringAsync();
    var result = JObject.Parse(body);

    IList<JToken> results = result["uk"]["ghs"]["products"]["results"].Children().ToList();

    //// serialize JSON results into .NET objects
    IList<Product> products = new List<Product>();
    foreach (JToken r in results)
    {
        // JToken.ToObject is a helper method that uses JsonSerializer internally
        Product product = r.ToObject<Product>();
        products.Add(product);
    }
    return View(products);  

我有AddToCart方法：

public void AddToCart(Product Product)
{
    var cartItem = listDB.Carts.SingleOrDefault(c => c.CartId == ShoppingCartId && c.Id == Product.ID);
    if (cartItem == null)
    {
        cartItem = new Cart
        {
            Id = Product.ID,
            CartId = ShoppingCartId,
            Count = 1,
            DateCreated = DateTime.Now
        };
        listDB.Carts.Add(cartItem);
    }
    else {
        cartItem.Count++;
    }
    listDB.SaveChanges();

}

这是我的ShoppingCartController和ActionResult方法：

public ActionResult AddToCart(string name)
{
    var addedProduct = listDB.products.FirstOrDefault(product => product.Name == name);
    var cart = ShoppingCart.GetCart(this.HttpContext);
    cart.AddToCart(addedProduct);
    return RedirectToAction("Index");
}

但是由于某些原因，当我单击“添加”按钮时，以下异常显示：

System.Reflection.TargetException was unhandled by user code
  HResult=-2146232829
  Message=Non-static method requires a target.
  Source=mscorlib

产品信息返回空运行时异常

如何修改AddToCart方法以从TescoLabsApi接收产品信息，然后将其添加到购物车中？

Answer 1

我认为这可能是错误的地方。

var cart = ShoppingCart.GetCart(this.HttpContext);

ShoppingCart参考的价值是什么-它在哪里定义？