using System;

using System.Linq;

using System.Collections.Generic;

​

class TestA {

    public int first { get; set; }

    public int second { get; set;}

}

public class Program

{

    public static void Main()

    {

        var firstObject = new TestA{

            first = 1,

            second = 2

        };

        var secondObject = new TestA{

            first = 3,

            second = 4

        };

        var objectList = new List<TestA>();

        objectList.Add(firstObject);

        objectList.Add(secondObject);

        // var listCopy = new List<TestA>();

        var listCopy = objectList.ToList();

        firstObject.first = -1;

        Console.WriteLine(listCopy[0].first);

        Console.WriteLine("Hello World");

    }

}