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.

Answer 1

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