using System;

using Newtonsoft.Json.Linq;

using Newtonsoft.Json;

public class Program

{

    public static void Main()

    {

        var x = new {a = 3, b= "a string", c = (string)null, e = new {f = 3}};

        var s = JsonConvert.SerializeObject(x);

        Console.WriteLine(s);

        dynamic o = JsonConvert.DeserializeObject(s);

        Console.WriteLine(o.a == null);

        Console.WriteLine(o.b == null);

        Console.WriteLine(o.c == null);

        Console.WriteLine(o.d == null);

        Console.WriteLine(o.ContainsKey("a"));

        Console.WriteLine(o.ContainsKey("b"));

        Console.WriteLine(o.ContainsKey("c"));

        Console.WriteLine(o.ContainsKey("d"));

        Console.WriteLine(o.e.ContainsKey("f"));

        Console.WriteLine(o.e.ContainsKey("g"));

    }

}