将数据从视图传递到控制器时出错

Question

我在视图页面上有一个按钮，它通过传递一个 ID 值连接到另一个控制器。

控制器

public class CartController : Controller
{
    ......
    [Route("index")]
    public IActionResult Index()
    {
        var cart = SessionHelper.GetObjectFromJson<List<Item>>(HttpContext.Session, "cart");
        ViewBag.cart = cart;
        return View();
    }

    [Route("buy/{customerID}/{invetoryID}")]
    public async Task<IActionResult> Buy(int? customerID, int? invetoryID)
    {
        if (customerID == null || invetoryID == null)
        {
            return NotFound();
        }
        Customer custData = await _context.Customers.FindAsync(customerID);
        var intData = await _context.Inventories.FindAsync(invetoryID);

        if (SessionHelper.GetObjectFromJson<List<Item>>(HttpContext.Session, "cart") == null)
        {
            List<Item> cart = new List<Item>();
            cart.Add(new Item
            {
                Custom = custData,
                Inventory = intData,
                Quantity = 1
            });
            SessionHelper.SetObjectAsJson(HttpContext.Session, "cart", cart);
        }           
        return RedirectToAction("Index");
    } }}

型号

public class Item
{
    public Customer Custom { get; set; }
    public Inventory Inventory { get; set; }
    public int Quantity { get; set; }
}

如下图所示

<table cellpadding="2" cellspacing="2" border="1">
   .......
    @{var dataCart = ViewBag.cart; }
    @foreach (var item in ViewBag.cart)
    {
        <tr>
            <td>@item.Inventory.StrainId</td>
            <td>@item.Inventory.StrainName</td>
            <td>@item.Quantity</td>
        </tr>
    }
 </table>
 <br>
<a asp-action="Index" asp-controller="Inventories" asp-route-id="@dataCart.Custom.CustomerId">Select</a>
</body>
</html>

当我加载页面时它会抛出错误，它会抛出像RuntimeBinderException: 'System.Collections.Generic.List<JAXSurplusMouseApp.Models.Item>' does not contain a definition for 'Custom'这样的错误

即使 Item 模型和 ViewBag 具有 Custom，它也不会抛出任何定义。谁能告诉我在这里想念什么。如果我没有按钮，那么页面加载非常好。

 <a asp-action="Index" asp-controller="Inventories" asp-route-id="@dataCart.Custom.CustomerId">Select</a>

Answer 1

你必须修正你的观点

@if ( @ViewBag.cart != null && ViewBag.cart.Count>0)
{
<a asp-action="Index" asp-controller="Inventories" asp-route-id=" @ViewBag.cart[0].Custom.CustomerId">Select</a>
}
````
or  place ancor inside of foreach
````
 @foreach (var item in ViewBag.cart)
    {
        <tr>
            <td>@item.Inventory.StrainId</td>
            <td>@item.Inventory.StrainName</td>
            <td>@item.Quantity</td>
             <td>
<a asp-action="Index" asp-controller="Inventories" asp-route-id="@item.Custom.CustomerId">Select</a>
            </td>
        </tr>
    }
 </table>
 <br>