WCF Web API dynamic JsonNet

WCfWebApiDynamicProgran.cs

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using Microsoft.ApplicationServer.Http;
using System.ServiceModel;
using System.Net.Http;
using System.ServiceModel.Web;
using System.Net.Http.Headers;
using WebApiContrib.Formatters.JsonNet;

namespace TestSerializationWcf
{
    class Program
    {
        static void Main(string[] args)
        {
            string endpoint = "http://localhost:232/test";
            var config = new WebApiConfiguration();
            config.EnableTestClient = true;
            config.Formatters.Insert(0, new JsonNetFormatter());

            using (var host = new HttpServiceHost(typeof(MyService), config, endpoint))
            {
                host.Open();
                var client = new HttpClient();
               
                client.DefaultRequestHeaders.Accept.Add(new MediaTypeWithQualityHeaderValue("application/json"));
                client.BaseAddress = new Uri(endpoint);

                var response = client.PostAsync("", new ObjectContent<SampleMessage>(new SampleMessage { Foo = "bar", Blah = new { StringType = "AAA" } },
                    new MediaTypeWithQualityHeaderValue("application/json"), new[] { new JsonNetFormatter() })).Result;

                var result = response.Content.ReadAsAsync<SampleOutput>(new [] { new JsonNetFormatter() }).Result;
                Console.WriteLine(result.Foo);
                dynamic a = result.Blah;
                Console.WriteLine(a.Boo);
                Console.ReadLine();
            }
        }
    }

    [ServiceContract]
    class MyService
    {
        [WebInvoke(UriTemplate = "")]
        public HttpResponseMessage<SampleOutput> Test(HttpRequestMessage<SampleMessage> request)
        {
            SampleMessage req = request.Content.ReadAsAsync().Result;
            SampleOutput output = new SampleOutput { Foo = req.Foo, Blah = new { Boo = req.Blah.StringType } };
            return new HttpResponseMessage<SampleOutput>(output);
        }
    }

    public class SampleMessage
    {
        public string Foo { get; set; }
        public dynamic Blah { get; set; }
    }

    public class SampleOutput
    {
        public string Foo { get; set; }
        public dynamic Blah { get; set; }
    }
}