WebApi 2.0 RouteAttribute中的错误

Question

这是我的Global.asax

    protected void Application_Start()
    {
        RegisterRoutes();
    }

    private static void RegisterRoutes()
    {
        AreaRegistration.RegisterAllAreas();

        GlobalConfiguration.Configure(WebApiConfig.Register);
        FilterConfig.RegisterGlobalFilters(GlobalFilters.Filters);
        RouteConfig.RegisterRoutes(RouteTable.Routes);

        GlobalConfiguration.Configure(x => x.MapHttpAttributeRoutes());
        GlobalConfiguration.Configuration.EnsureInitialized();
    }

这是我的Web控制器

    [RoutePrefix("api/admin/users/")]
    public class UsersController : ApiController
    {
        [Route("get")]
        public IQueryable<User> GetUsers()
        {
            return db.Users;
        }
    }

下面是我导航到localhost时遇到的错误:123/api/admin/user/ get

The object has not yet been initialized. Ensure that HttpConfiguration.EnsureInitialized() is called in the application's startup code after all other initialization code.

我不知道我在这里做错了什么。我相信我正在为新的WebApi 2.0方法做好一切，但我遗漏了一些东西。

提前谢谢。

更新

这是堆栈，以防万一，这是有帮助的

at System.Web.Http.Routing.RouteCollectionRoute.GetRouteData(String virtualPathRoot, HttpRequestMessage request) 
at System.Web.Http.WebHost.Routing.HttpWebRoute.GetRouteData(HttpContextBase httpContext)

Answer 1

请移除

    GlobalConfiguration.Configure(x => x.MapHttpAttributeRoutes());

来自Global.asax。

然后在WebApiConfig.cs中调用MapHttpAttributeRoutes

    public static void Register(HttpConfiguration config)
    {
        config.MapHttpAttributeRoutes();
    }

Answer 2

在我的例子中，由于在WebApi之前配置Autofac，所以我得到了这个错误：

GlobalConfiguration.Configure(WebApiConfig.Register);
GlobalConfiguration.Configure(AutofacConfig.Register);

改变命令让我克服了这个问题：

GlobalConfiguration.Configure(AutofacConfig.Register);
GlobalConfiguration.Configure(WebApiConfig.Register);