MvcActionValueBinder Execption in post about webapicontrib HOT 9 OPEN

public class MvcActionValueBinder : DefaultActionValueBinder
 {
        // Per-request storage, uses the Request.Properties bag. We need a unique key into the bag.
        private const string Key = "{5DC187FB-BFA0-462A-AB93-9E8036871EC8}";

        public override HttpActionBinding GetBinding(HttpActionDescriptor actionDescriptor)
        {
            var actionBinding = new MvcActionBinding();

            HttpParameterDescriptor[] parameters = actionDescriptor.GetParameters().ToArray();
            HttpParameterBinding[] binders = Array.ConvertAll(parameters, DetermineBinding);

            actionBinding.ParameterBindings = binders;

            return actionBinding;
        }

        private HttpParameterBinding DetermineBinding(HttpParameterDescriptor parameter)
        {
            HttpConfiguration config = parameter.Configuration;
            var attr = new ModelBinderAttribute(); // use default settings

            ModelBinderProvider provider = attr.GetModelBinderProvider(config);
            IModelBinder binder = provider.GetBinder(config, parameter.ParameterType);

            // Alternatively, we could put this ValueProviderFactory in the global config.
            var vpfs = new List<ValueProviderFactory>(attr.GetValueProviderFactories(config)) { new BodyValueProviderFactory() };
            return new ModelBinderParameterBinding(parameter, binder, vpfs);
        }

        // Derive from ActionBinding so that we have a chance to read the body once and then share that with all the parameters.
        private class MvcActionBinding : HttpActionBinding
        {
            // Read the body upfront , add as a ValueProvider
            public override Task ExecuteBindingAsync(HttpActionContext actionContext, CancellationToken cancellationToken)
            {
                HttpRequestMessage request = actionContext.ControllerContext.Request;
                HttpContent content = request.Content;
                if (content != null)
                {
                    FormDataCollection fd = content.ReadAsAsync<FormDataCollection>().Result;
                    if (fd != null)
                    {
                        IValueProvider vp = new NameValuePairsValueProvider(fd, CultureInfo.InvariantCulture);
                        request.Properties.Add(Key, vp);
                    }
                }

                return base.ExecuteBindingAsync(actionContext, cancellationToken);
            }
        }

        // Get a value provider over the body. This can be shared by all parameters.
        // This gets the values computed in MvcActionBinding.
        private class BodyValueProviderFactory : ValueProviderFactory
        {
            public override IValueProvider GetValueProvider(HttpActionContext actionContext)
            {
                object vp;
                actionContext.Request.Properties.TryGetValue(Key, out vp);
                return (IValueProvider)vp; // can be null 
            }
        }
    }

FormDataCollection fd = content.ReadAsAsync<FormDataCollection>().Result;

var fd = content.ReadAsAsync<IDictionary<string, object>>().Result;