using System;

using System.Collections.Generic;

public class Program

{

    public class MyObject

    {

        public int Id{get;set;}

    }

    public static void Main()

    {

        var v1 = new MyObject(){Id=1};

        var v2 = new MyObject(){Id=2};

        var v3 = new MyObject(){Id=1};

        var v4 = v1;

        Console.WriteLine(v1.Equals(v2));

        Console.WriteLine(v1.Equals(v3));

        Console.WriteLine(v1.Equals(v4));

        var d = new Dictionary<MyObject,string>();

        if(!d.ContainsKey(v1))

            d.Add(v1,"V1");

        d.Add(v2,"V2");

        d.Add(v3,"V3");

        if(d.ContainsKey(v4))

            Console.WriteLine("Exists");

        else

            d.Add(v4,"V4"); //Should fail

        foreach(var kv in d)

            Console.WriteLine($"{kv.Key.Id} {kv.Value}");

        Console.WriteLine("\nEnd");

    }

}