Sequence contains no elements - no info in stack trace

Question

Getting an error in my (at this stage) simple c# MVC3 (Razor) application, and I can't seem to find out what is causing the error below.

[InvalidOperationException: Sequence contains no elements]
   System.Linq.Enumerable.Last(IEnumerable`1 source) +4188046
   RouteDebug.RouteDebuggerHttpModule.OnBeginRequest(Object sender, EventArgs e) +78
   System.Web.SyncEventExecutionStep.System.Web.HttpApplication.IExecutionStep.Execute() +148
   System.Web.HttpApplication.ExecuteStep(IExecutionStep step, Boolean& completedSynchronously) +75

this is all I get, no line numbers, no nothing.

I've tried putting breakpoints in various locations in the code, including the application_start sectin of Global.asax.cs, but these never get hit, the program just immediately bombs out with the stack trace as soon as i start debugging.

The structure of the application is as follows:

[Application.Core]
+Properties
+Reference
+Controllers
+Helpers
+Models
+AdminAreaRegistration.cs
+Global.asax.cs
[Application.Tests]
[Application.UI]
+Properties
+References
+App_Data
+Areas
    +Admin
        +Views
+Assets (css/js/images)
+Views

I've tried a few suggestions already, including adding the Application.Core namespace to the AdminAreaRegistration.cs file, and removing obj/bin and rebuilding.

I just can't see whats causing the problem.

Update

AdminAreaRegistration.cs

using System.Web.Mvc;

namespace Application.Core
{
    public class AdminAreaRegistration : AreaRegistration
    {
        public override string AreaName
        {
            get
            {
                return "Admin";
            }
        }

        public override void RegisterArea(AreaRegistrationContext context)
        {
            context.MapRoute(
                "Admin_default",
                "Admin/{controller}/{action}/{id}",
                new {controller = "Page", action = "Index", id = UrlParameter.Optional }
            );
        }
    }
}

Global.asax.cs

using System;
using System.Collections.Generic;
using System.Linq;
using System.Web;
using System.Web.Mvc;
using System.Web.Routing;

namespace Application.Core
{
    // Note: For instructions on enabling IIS6 or IIS7 classic mode, 
    // visit http://go.microsoft.com/?LinkId=9394801

    public class MvcApplication : System.Web.HttpApplication
    {
        public static void RegisterGlobalFilters(GlobalFilterCollection filters)
        {
            filters.Add(new HandleErrorAttribute());
        }

        public static void RegisterRoutes(RouteCollection routes)
        {
            routes.IgnoreRoute("{resource}.axd/{*pathInfo}");

            routes.MapRoute(
                "Default", // Route name
                "{controller}/{action}/{id}", // URL with parameters
                new { controller = "Page", action = "Homepage", id = UrlParameter.Optional } // Parameter defaults
            );

        }

        protected void Application_Start()
        {
            AreaRegistration.RegisterAllAreas();

            RegisterGlobalFilters(GlobalFilters.Filters);
            RegisterRoutes(RouteTable.Routes);
        }
    }
}

do you have "glimpse" or [RouteDebugger](http://nuget.org/packages/routedebugger) or anything similar installed? `RouteDebuggerHttpModule` sounds very suspect here... — Marc Gravell, Sep 13 '12 at 08:31
I have Phil Haack's routedebugger (2.1.4.0) installed when i first started the app. It has been working, but since (I think) I created an area and moved the views into this area I've been getting this error. But i couldn#'t tell you exactly when it started. — kolin, Sep 13 '12 at 08:34
Looks like it is something to do with the Admin area that I have set up, I'm going to have to look into this later, as other projects call. — kolin, Sep 24 '12 at 11:10

score 2 · Accepted Answer · answered Sep 13 '12 at 08:39

2

Glancing at RouteDebugger in reflector, the offending code is:

private static void OnBeginRequest(object sender, EventArgs e)
{
    if (RouteTable.Routes.Last<RouteBase>() != DebugRoute.Singleton)
    {
        RouteTable.Routes.Add(DebugRoute.Singleton);
    }
}

So: it sounds like somehow you have no routes. However, I would also wonder whether this module should actually use LastOrDefault, or basically cope better with this scenario.

Have you ensured that you have the current and up-to-date version of RouteDebugger ?

As for why you have no routes: maybe the pipeline is running in a different order now? First thing to do: remove that module and see if everything else works. If the site works fine minus that module, then ask Phil about it.

answered Sep 13 '12 at 08:39

Marc Gravell

1,026,079
266
2,566
2,900

I've added the Routes for Admin and Global into the original question just to see if there is anything glaringly obvious that i've missed – kolin Sep 13 '12 at 09:05
I removed the RouteDebugger from the solution using nuget, and I get a 404 which implies to me that the routes aren't either working or not registered... would this be correct? – kolin Sep 13 '12 at 10:09
@kolin yes, fix that *first*, then put `RouteDebugger` back in. Sounds like you deleted the line in global.asax that configures the routing table. – Marc Gravell Sep 13 '12 at 11:15

score 0 · Answer 2 · answered Sep 13 '12 at 08:32

0

It's caused my calling the extension method Last() on a collection that has no elements, or calling Last(expression) on a collection that has no matching elements.

I would do a search through my code to try and identify where you have used this kind of calls. (just do a search in entire solution)

My best guess is that you have put this logic directly into one of your views, and not in the controller.

answered Sep 13 '12 at 08:32

Øyvind Bråthen

59,338
27
124
151

There is no logic hardcoded into the views. all logic to populate the views are produced in the controllers, and all linq queries end in FirstOrDefault – kolin Sep 13 '12 at 08:41

Sequence contains no elements - no info in stack trace

2 Answers2