using System;

using System.Collections.Generic;

using Newtonsoft.Json;

public class Program

{

    public enum ConfigItemType {

        String,

        Int,

        NumberList

    }

    public interface IConfigItem {

        ConfigItemType ConfigType { get; set; }

    }

    public class ConfigNumberList : IConfigItem {

        public ConfigItemType ConfigType { get; set; }

        public Dictionary<int, string> Value { get; set; }

    }

    public class ConfigurationService {

        public Dictionary<string, object> _dict = new Dictionary<string, object>();

        public void Add<T>(string key, T value) where T : class, IConfigItem {

            _dict.Add(key, value);  

        }

        public T GetValue<T>(string key) where T : class, IConfigItem {

            return _dict[key] as T; 

        }

    }

    public static void Main()

    {

        var cfg = new ConfigurationService();

        var list = new ConfigNumberList();

        list.Value = new Dictionary<int, string>() {

            { 100, "Materiaal" },

            { 101, "Kabel" },

            { 102, "Whatever" }

        };

        cfg.Add<ConfigNumberList>("test", list);

        string json = JsonConvert.SerializeObject(cfg, Formatting.Indented, new JsonSerializerSettings{TypeNameHandling = TypeNameHandling.All});

        ConfigurationService config = JsonConvert.DeserializeObject<ConfigurationService>(json, new JsonSerializerSettings {TypeNameHandling = TypeNameHandling.Auto});

        Console.WriteLine(json);

        var dList = config.GetValue<ConfigNumberList>("test");

        Console.WriteLine(dList.Value[100]);

    }

}