InvalidOperationException thrown regarding DotNetOpenAuth.IEmbeddedResourceRetrieval with Razor view

Question

When my Razor view calls @Html.OpenIdSelector(... I get an InvalidOperationException:

The current IHttpHandler is not one of

Answer 1

I came across this problem when I was trying to get the NerdDinner OpenID working for MVC3/razor. The solution that has worked for me is:

Create this class in your solution: (this was found in one of the NerdDinner builds - http://nerddinner.codeplex.com/SourceControl/changeset/view/55257#1328982 (thanks to JasonHaley) for some reason, this file isn't in the latest build for NerdDinner MVC3/Razor

using System;
using System.Collections.Generic;
using System.Linq;
using System.Web;
using System.Web.Mvc;
using DotNetOpenAuth;
namespace .Services
{
    public class EmbeddedResourceUrlService : IEmbeddedResourceRetrieval
    {

        private static string pathFormat = "{0}/{1}/Resource/GetWebResourceUrl?assemblyName={2}&typeName={3}&resourceName={‌​4}";
        //private static string pathFormat = "{0}/Resource/GetWebResourceUrl";

        public Uri GetWebResourceUrl(Type someTypeInResourceAssembly, string manifestResourceName)
        {
            if (manifestResourceName.Contains("http"))
            {
                return new Uri(manifestResourceName);
            }
            else
            {
                var assembly = someTypeInResourceAssembly.Assembly;

                // HACK
                string completeUrl = HttpContext.Current.Request.Url.ToString();
                string host = completeUrl.Substring(0,
                    completeUrl.IndexOf(HttpContext.Current.Request.Url.AbsolutePath));

                var path = string.Format(pathFormat,
                            host,
                            HttpContext.Current.Request.ApplicationPath.Substring(1),
                            HttpUtility.UrlEncode(assembly.FullName),
                            HttpUtility.UrlEncode(someTypeInResourceAssembly.ToString()),
                            HttpUtility.UrlEncode(manifestResourceName));

                return new Uri(path);
            }
        }
    }
}

Then in your web.config, add this line:

just put in the DotNetOpenAuth section

you will also need this route set up: ( Html.OpenIdSelectorScripts helper method throwing NullReferenceException )

    routes.MapRoute(
        "OpenIdDiscover",
        "Auth/Discover"
    );