using Newtonsoft.Json;  

​

public class Program

{

    public static void Main()

    {

        var settings = new JsonSerializerSettings();

        //settings.Error = (sender, args) =>

        //{

        //    args.ErrorContext.Handled = true;

        //};

        var json = @"

{

    'id': 'aa',

    'type': null

}";

        JsonConvert.DeserializeObject<Code>(json, settings);

    }

}

​

public class Code

{

    [JsonProperty("id", Required = Required.Always)]

    public string id { get; set; }

​

    [JsonProperty("type", Required = Required.Always)]

    public string type { get; set; }

}