JSON.NET: ConcreteTypeConverter and ConcreteTypeListConverter classes for deserialization of interface properties

ConcreteTypeConverter

using System;
using System.Collections.Generic;
using System.Linq;
using Newtonsoft.Json;

public class ConcreteTypeConverter<TConcrete> : JsonConverter {
    public override bool CanConvert(Type objectType) {
        //this method is *not* called when using the JsonConverterAttribute to assign a converter
        return objectType.IsAssignableFrom(typeof (TConcrete));
    }

    public override object ReadJson(JsonReader reader, Type objectType, object existingValue,
                                    JsonSerializer serializer) {
        //explicitly specify the concrete type we want to create
        return serializer.Deserialize<TConcrete>(reader);
    }

    public override void WriteJson(JsonWriter writer, object value, JsonSerializer serializer) {
        //use the default serialization - it works fine
        serializer.Serialize(writer, value);
    }
}

ConcreteTypeListConverter

using System;
using System.Collections.Generic;
using System.Linq;
using Newtonsoft.Json;

public class ConcreteTypeListConverter<TInterface, TItem> : JsonConverter where TItem : TInterface {
    public override bool CanConvert(Type objectType) {
        //this method is *not* called when using the JsonConverterAttribute to assign a converter
        return IsIList(objectType) || objectType.GetInterfaces().Any(IsIList);
    }

    private static bool IsIList(Type objectType) {
        return objectType.IsGenericType && objectType.GetGenericTypeDefinition() == typeof (IList<>);
    }

    public override object ReadJson(JsonReader reader, Type objectType, object existingValue,
                                    JsonSerializer serializer) {
        //explicitly specify the concrete type we want to create
        var specializedList = serializer.Deserialize<List<TItem>>(reader);
        return specializedList.Cast<TInterface>().ToList();
    }

    public override void WriteJson(JsonWriter writer, object value, JsonSerializer serializer) {
        //use the default serialization - it works fine
        serializer.Serialize(writer, value);
    }
}

Thanks again for that tidbit ! It did the trick, as expected :-)