gistfile1.txt

 public class FormHandler : DelegatingHandler
    {
        protected override System.Threading.Tasks.Task<HttpResponseMessage> SendAsync(HttpRequestMessage request, System.Threading.CancellationToken cancellationToken)
        {
            if (request.Content != null && request.Content.Headers.ContentType != null &&
                request.Content.Headers.ContentType.MediaType == "application/x-www-form-urlencoded")
            {
                var routeData = request.Properties["MS_HttpRouteData"] as IHttpRouteData;
                
                var form = request.Content.ReadAsFormDataAsync().Result;
                foreach (var key in form.AllKeys)
                {
                    routeData.Values.Add(new KeyValuePair<string, object>(key, form[key]));
                }
            }
            return base.SendAsync(request, cancellationToken);
        }
    }