using System;

using System.Collections;

using System.Collections.Generic;

using Newtonsoft.Json;

using Newtonsoft.Json.Linq;

public class Program

{

    public static void Main()

    {

        Model model = new Model

        {

            ID = 1,

            Dic = new Dictionary<string, string>

            {

                { "name1", "value1" },

                { "name2", "value2" }

            }

        };

        string json = JsonConvert.SerializeObject(model, Formatting.Indented);

        Console.WriteLine(json);

    }

}

​

​

public class Model

{

    public int ID { get; set; }

    [JsonConverter(typeof(CustomDictionaryConverter))]

    public Dictionary<string, string> Dic { get; set; }

}

​

public class CustomDictionaryConverter : JsonConverter

{

    public override bool CanConvert(Type objectType)

    {

        return typeof(IDictionary).IsAssignableFrom(objectType);

    }

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

    {

        IDictionary dict = (IDictionary)value;

        JArray array = new JArray();

        foreach (DictionaryEntry kvp in dict)

        {

            JObject obj = new JObject();

            obj.Add(kvp.Key.ToString(), kvp.Value != null ? JToken.FromObject(kvp.Value, serializer) : new JValue((string)null));

            array.Add(obj);

        }

        array.WriteTo(writer);

    }

    public override bool CanRead

    {

        get { return false; }

    }

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

    {

        throw new NotImplementedException();

    }

}

​