using System;

using Newtonsoft.Json;

​

public class Program

{

    public static void Main()

    {

        ConfigFile f = ConfigFile.Load();

        f.ServerAddress = "0.0.0.0";

        f.ServerPort = "8080";

        f.ServerTimeout = "400";

        f.Save();

    }

    public class ConfigFile

    {

        private readonly static string path = "somePath.json";

        public string ServerAddress { get; set; }

        public string ServerPort { get; set; }

        public string ServerTimeout { get; set; }

        public void Save()

        {

            var json = JsonConvert.SerializeObject(this, Formatting.Indented);

            // File.WriteAllText(path, json) 

            Console.WriteLine(json);

        }

        public static ConfigFile Load()

        {

            //// var json = File.ReadAllText(path); 

            var json = @"{ 

                ServerAddress: null, 

                ServerPort: null, 

                ServerTimeout: null }";

            return JsonConvert.DeserializeObject<ConfigFile>(json);

        }

    }

}