ASP.NET MVC 3 服务器错误

我有以下控制器：

public class ItemController : Controller
{
    private SomeDbEntities _db= new SomeDbEntities ();
    //
    // GET: /Item/
    public ActionResult Index()
    {
        var items = _db.Items.ToList();
        return View(items);
    }
    public ActionResult Decription(int id)
    {
        var item = _db.Items.Single(a => a.ItemID == id);
        return View(item); 
    }
}

和 2 个视图：

Index.cshmtl

@model IEnumerable<Web.Models.Item>
@{
    ViewBag.Title = "Index";
 }
<h2>Index</h2>
<ul>
@foreach (var item in Model)
{
    <li>@Html.ActionLink(item.Name, "Description", new { id = item.ItemID})</li>
}

Description.cshtml

@model Web.Models.Item
@{
    ViewBag.Title = "Decription";
 }
 <h2>Decription</h2>
 <p>@Model.Description</p>

路线

public static void RegisterRoutes(RouteCollection routes)
    {
        routes.IgnoreRoute("{resource}.axd/{*pathInfo}");
        routes.MapRoute(
            name: "Default",
            url: "{controller}/{action}/{id}",
            defaults: new { controller = "Item", action = "Index", id = UrlParameter.Optional }
        );
        routes.MapHttpRoute(
            name: "DefaultApi",
            routeTemplate: "api/{controller}/{id}",
            defaults: new { id = RouteParameter.Optional }
        );

    }

当我试图达到即 http://localhost:12952/Item/Description/2我收到服务器错误：

HTTP 404. The resource you are looking for (or one of its dependencies) could have been removed, had its name changed, or is temporarily unavailable.