using System;

using System.Collections.Generic;

using System.Linq;

using Newtonsoft.Json;

public class Program

{

    public static void Main()

    {

        string json = @"{""A"":727657,""B"":""72.74:hello"",""C"":""Http"",""D"":""Value:0,Value1:79,Value2:56,Value3:45"",""E"":0,""F"":2}";

        MyJSONContructor MyJSONContructorObject = JsonConvert.DeserializeObject<MyJSONContructor>(json);

        List<KeyValuePair<string, string>> kvps = 

            (from pair in MyJSONContructorObject.D.Split(',')

             let kv = pair.Split(':')

             select new KeyValuePair<string, string>(kv[0], kv[1])

            ).ToList();

        foreach (var kvp in kvps)

            Console.WriteLine(kvp.Key + " = " + kvp.Value);

    }

}

​

public class MyJSONContructor

{

    public int A { get; set; }

    public string B { get; set; }

    public string C { get; set; }

    public string D { get; set; }

    public int E { get; set; }

    public int F { get; set; }

}