using System;

using System.Collections.Generic;   

using Newtonsoft.Json;

​

public class Program

{

    public static void Main()

    {

        var collection = new Dictionary<string,object>()

        {

            { "PayloadSize", 1208 },

            { "PayloadCount", 1 },

            { "NotificationUrl", "http://my.url.com/for_show_only" }

        };

        Console.WriteLine("With No Special Wrap: " + ToList(collection));

    }

​

    private static string ToList(IDictionary<string, object> collection)

    {

        return "json=" + JsonConvert.SerializeObject(collection, formatting: Formatting.None);

    }

}