using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Runtime.CompilerServices;

namespace ConsoleApplication1 {
    class Node : Dictionary<object, dynamic> {
        public Node add_chain(object key, dynamic node) {
            this.Add(key, node);
            return this;
        }
    }

    class Program {
        struct TData1 {
            public string data1;
        }

        static void Main(string[] args) {
            var root = new Node(
            ).add_chain(
                "key1_level1",
                new Node(
                ).add_chain(
                    "key1_level2",
                    new TData1() { data1 = "test1" }
                )
            ).add_chain(
                "key2_level1",
                123456
            );
            Console.WriteLine(root["key1_level1"]["key1_level2"].data1);
            Console.WriteLine(root["key2_level1"]);
            Console.ReadKey();
        }
    }
}