using System;

using System.Collections.Generic;

public class Program

{

    public static void Main()

    {

        var a = new Dictionary<dynamic, dynamic>{};

        a[1] = "integer";

        a["1"] = "string";

        a[new Dictionary<string, string>{}] = "dict";

        a[new int[] {1, 2, 3}] = "array";

        Console.WriteLine(a[1]);

        Console.WriteLine(a["1"]);

        Console.WriteLine(a.ContainsKey(new Dictionary<string, string>{}));

        Console.WriteLine(a.ContainsKey(new int[] {1, 2, 3}));

    }

}

​