Type missing when Asp.net MVC4 website starts

Question

When I start an Asp.net MVC4 website in visual studio 2012. I was stuck with an exception said :

Could not load type 'System.Net.Http.Formatting.DefaultContentNegotiator' 
from assembly 'System.Net.Http.Formatting, Version=4.0.0.0, Culture=neutral,
PublicKeyToken=31bf3856ad364e35'.

On the code :

routes.MapHttpRoute(
                name: "DefaultApi",
                routeTemplate: "api/{controller}/{id}",
                defaults: new { id = System.Web.Http.RouteParameter.Optional }
            );

the Whole code looks like :

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


namespace Accela.Apps.Diagnostics.Portal
{
    public class RouteConfig
    {
        public static void RegisterRoutes(RouteCollection routes)
        {
            routes.IgnoreRoute("{resource}.axd/{*pathInfo}");

            routes.MapHttpRoute(
                name: "DefaultApi",
                routeTemplate: "api/{controller}/{id}",
                defaults: new { id = System.Web.Http.RouteParameter.Optional }
            );


            routes.MapRoute(
               name: "Default",
               url: "{controller}/{action}/{id}",
               defaults: new { controller = "Login", action = "Login", id = UrlParameter.Optional }
           );
        }
    }
}

Please help get me out of there.thanks.

score 2 · Accepted Answer · answered Dec 17 '12 at 09:30

2

Looks like you are having old version of the DLL. What you can do is, remove the existing reference to 'System.Net.Http.Formatting' from your project and try installing this

answered Dec 17 '12 at 09:30

Siddaraju

96
5

thanks ,Did you attention this line `Legacy package, System.Net.Http.Formatting is now included in the 'Microsoft.AspNet.WebApi.Client'package` in the page you provided? – Joe.wang Dec 17 '12 at 09:34
The web site I created is a `Web Api` project. `System.Net.Http.Formatting` is already include in it . Should I remove the existing one ? thanks. – Joe.wang Dec 17 '12 at 09:39
1

Hey Joe, I understand. Can you right click on 'System.Net.Http.Formatting' under project references and do 'view in Object Browser' then you can check 'DefaultContentNegotiator' is available. – Siddaraju Dec 17 '12 at 09:45
Hi Sids, After I checked it , I found the public class `DefaultContentNegotiator` is already a Member of `System.Net.Http.Formatting` namespace. thanks. – Joe.wang Dec 17 '12 at 09:49
Hi Sids, The version of the dll cause the problem. I had updated it. thanks. – Joe.wang Dec 17 '12 at 10:05
1

[See this](http://stackoverflow.com/questions/9431975/could-not-load-file-or-assembly-system-net-http-version-2-0-0-0-in-mvc4-web-ap) this should give you some idea – Siddaraju Dec 17 '12 at 10:08

score 0 · Answer 2 · answered Dec 17 '12 at 09:26

0

Should that optional parameter not just be

UrlParameter.Optional

as in

routes.MapHttpRoute(
                name: "DefaultApi",
                routeTemplate: "api/{controller}/{id}",
                defaults: new { id = UrlParameter.Optional  }
            );

instead of System.Web.Http.RouteParameter.Optional

answered Dec 17 '12 at 09:26

dove

20,469
14
82
108

Still has the same exception. Thanks. – Joe.wang Dec 17 '12 at 09:31

Type missing when Asp.net MVC4 website starts

2 Answers2