WebApi 2.0 RouteAttribute 出错

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 Api 控制器

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

这是我导航到 localhost:123/api/admin/users/get 时遇到的错误

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。我相信我为新的 WebApi 2.0 方式做的一切都是正确的，但我错过了一些东西。

提前致谢。

更新

这是堆栈以防万一

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

Answer 1

请删除

    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

就我而言，我收到此错误是因为我在 WebApi 之前配置 Autofac：

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

更改顺序让我解决了这个问题：

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