using System;

using Newtonsoft.Json;

public class Videogame

{

    [JsonProperty(Required = Required.Always)]

    public string Name { get; set; }

​

    [JsonProperty(Required = Required.AllowNull)]

    public DateTime? ReleaseDate { get; set; }

}

​

public class Program

{

    public static void Main()

    {

        string json = @"{

          'ReleaseDate': null

        }";

        Videogame starcraft = JsonConvert.DeserializeObject<Videogame>(json);

        Console.WriteLine(starcraft.Name);

        // Starcraft III

        Console.WriteLine(starcraft.ReleaseDate);

    }

}