using System;

using System.Collections.Generic;

using System.Linq;

using Newtonsoft.Json;

using Newtonsoft.Json.Linq;

public class Program

{

    public static void Main()

    {

        var doc = new Document

        {

            Content = new Dictionary<Locale, string>

            {

                { Locale.English, "hello" },

                { Locale.Spanish, "hola" },

                { Locale.French, "bonjour" },

                { Locale.German, "hallo" }

            }

        };

        var settings = new JsonSerializerSettings();

        settings.Converters.Add(new LocaleDictionaryConverter());

        settings.Formatting = Formatting.Indented;

        string json = JsonConvert.SerializeObject(doc, settings);

        Console.WriteLine(json);

        Console.WriteLine();

        var doc2 = JsonConvert.DeserializeObject<Document>(json, settings);

        foreach (var kvp in doc2.Content)

        {

            Console.WriteLine(kvp.Key.Name + ": " + kvp.Value);

        }

    }

}

​

​

class Document

{

    public IDictionary<Locale, string> Content { get; set; }

}

​

​

class Locale

{

    public int Id { get; private set; }

    public string Abbreviation { get; private set; } // e.g. "en"

    public string Name { get; private set; }         // e.g. "English"

    private Locale(int id, string abbr, string name)

    {

        Id = id;

        Abbreviation = abbr;

        Name = name;

    }

    public static Locale FromAbbreviation(string abbreviation)

    {

        var locale = All.FirstOrDefault(l => l.Abbreviation == abbreviation);

        if (locale == null)

        {

            locale = English;

        }

        return locale;

    }

    public static readonly Locale English = new Locale(1, "en", "English");

    public static readonly Locale Spanish = new Locale(2, "es", "Spanish");

    public static readonly Locale French = new Locale(3, "fr", "French");

    public static readonly Locale German = new Locale(4, "de", "German");

    public static readonly Locale[] All = new Locale[] { English, Spanish, French, German };

}

​

​

class LocaleDictionaryConverter : JsonConverter

{

    public override bool CanConvert(Type objectType)

    {

        return typeof(IDictionary<Locale, string>).IsAssignableFrom(objectType);

    }

    public override object ReadJson(JsonReader reader, Type objectType, object existingValue, JsonSerializer serializer)

    {

        JObject obj = JObject.Load(reader);

        Dictionary<Locale, string> dict = new Dictionary<Locale, string>();

        foreach (var prop in obj.Properties())

        {

            dict.Add(Locale.FromAbbreviation(prop.Name), (string)prop.Value);

        }

        return dict;

    }

    public override void WriteJson(JsonWriter writer, object value, JsonSerializer serializer)

    {

        IDictionary<Locale, string> dict = (IDictionary<Locale, string>)value;

        JObject obj = new JObject();

        foreach (var kvp in dict)

        {

            obj.Add(kvp.Key.Abbreviation, kvp.Value);

        }

        obj.WriteTo(writer);

    }

}

​