WebApi 2.0 RouteAttribute 错误

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 时收到的错误

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。我相信我正在以新的 WebApi 2.0 方式正确执行所有操作，但我遗漏了一些东西。

提前致谢。

Update

这是堆栈，以防有帮助

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

请删除

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

from 全局.asax.

然后打电话MapHttpAttributeRoutes in the WebApiConfig.cs

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