using System;

using Newtonsoft.Json;

public class Program

{

    public static void Main()

    {

        var person = new Person

        {

            Name = "John",

            LastName = "Smith",

            Age = 13

        };

​

        var json = JsonConvert.SerializeObject(person, Formatting.Indented);

        Console.WriteLine(json);

    }

}

​

[JsonConverter(typeof(CustomConverter))]

public class Person

{

    public string Name { get; set; }

    public string LastName { get; set; }

    public int Age { get; set; }

}

​

public class CustomConverter : JsonConverter

{

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

    {

        if (value == null) return;

​

        writer.WriteStartObject();

        writer.WritePropertyName(value.GetType().Name);

​

        writer.WriteStartArray();

​

        var properties = value.GetType().GetProperties();

​

        foreach (var property in properties)

            writer.WriteValue(value.GetType().GetProperty(property.Name).GetValue(value));

​

        writer.WriteEndArray();

        writer.WriteEndObject();

    }

​

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

    {

        throw new NotImplementedException();

    }

​

    public override bool CanConvert(Type objectType)

    {

        return objectType == typeof (Person);

    }

}