using System;

using System.Collections.Generic;

using Newtonsoft.Json;

​

public class Program

{

    public static void Main()

    {

        var response = new OrderResponse();

        response.StringProp = "the string";

        response.DictProp = new Dictionary<string, object>

        {

            {"spareAlias1", "bar"},

            {"spareAlias2", 1}

        };

​

        Console.WriteLine(JsonConvert.SerializeObject(response, Formatting.Indented));

    }

}

​

class OrderResponse

{

    public string StringProp { get; set; }

​

    [JsonExtensionData]

    public Dictionary<string, object> DictProp { get; set; }

}