How to use Json.NET for JSON modelbinding in an MVC5 project?

I’ve finally found an answer. Basically I don’t need the MediaTypeFormatter stuff, that’s not designed to be used in MVC environment, but in ASP.NET Web APIs, that’s why I do not see those references and namespaces (by the way, those are included in the Microsoft.AspNet.WeApi NuGet package).

The solution is to use a custom value provider factory. Here is the code required.

    public class JsonNetValueProviderFactory : ValueProviderFactory
    {
        public override IValueProvider GetValueProvider(ControllerContext controllerContext)
        {
            // first make sure we have a valid context
            if (controllerContext == null)
                throw new ArgumentNullException("controllerContext");

            // now make sure we are dealing with a json request
            if (!controllerContext.HttpContext.Request.ContentType.StartsWith("application/json", StringComparison.OrdinalIgnoreCase))
                return null;

            // get a generic stream reader (get reader for the http stream)
            var streamReader = new StreamReader(controllerContext.HttpContext.Request.InputStream);
            // convert stream reader to a JSON Text Reader
            var JSONReader = new JsonTextReader(streamReader);
            // tell JSON to read
            if (!JSONReader.Read())
                return null;

            // make a new Json serializer
            var JSONSerializer = new JsonSerializer();
            // add the dyamic object converter to our serializer
            JSONSerializer.Converters.Add(new ExpandoObjectConverter());

            // use JSON.NET to deserialize object to a dynamic (expando) object
            Object JSONObject;
            // if we start with a "[", treat this as an array
            if (JSONReader.TokenType == JsonToken.StartArray)
                JSONObject = JSONSerializer.Deserialize<List<ExpandoObject>>(JSONReader);
            else
                JSONObject = JSONSerializer.Deserialize<ExpandoObject>(JSONReader);

            // create a backing store to hold all properties for this deserialization
            var backingStore = new Dictionary<string, object>(StringComparer.OrdinalIgnoreCase);
            // add all properties to this backing store
            AddToBackingStore(backingStore, String.Empty, JSONObject);
            // return the object in a dictionary value provider so the MVC understands it
            return new DictionaryValueProvider<object>(backingStore, CultureInfo.CurrentCulture);
        }

        private static void AddToBackingStore(Dictionary<string, object> backingStore, string prefix, object value)
        {
            var d = value as IDictionary<string, object>;
            if (d != null)
            {
                foreach (var entry in d)
                {
                    AddToBackingStore(backingStore, MakePropertyKey(prefix, entry.Key), entry.Value);
                }
                return;
            }

            var l = value as IList;
            if (l != null)
            {
                for (var i = 0; i < l.Count; i++)
                {
                    AddToBackingStore(backingStore, MakeArrayKey(prefix, i), l[i]);
                }
                return;
            }

            // primitive
            backingStore[prefix] = value;
        }

        private static string MakeArrayKey(string prefix, int index)
        {
            return prefix + "[" + index.ToString(CultureInfo.InvariantCulture) + "]";
        }

        private static string MakePropertyKey(string prefix, string propertyName)
        {
            return (String.IsNullOrEmpty(prefix)) ? propertyName : prefix + "." + propertyName;
        }
    }

And you can use it like this in your Application_Start method:

// remove default implementation    
ValueProviderFactories.Factories.Remove(ValueProviderFactories.Factories.OfType<JsonValueProviderFactory>().FirstOrDefault());
// add our custom one
ValueProviderFactories.Factories.Add(new JsonNetValueProviderFactory());

Here is the post which pointed me to the right direction, and also this one gave a good explanation on value providers and modelbinders.