using System;

using System.Linq;

using System.Collections.Generic;

public class Program

{

    public class Test

    {

        public string Name {get;set;}

        public Test(string name) {

            Name = name;

        }

    }

    public static void Main()

    {

        var items = new List<Test>();

        var first = new Test("a");

        var second = new Test("b");

        var third = new Test("a");

        // Current behavior

        foreach (var item in new[] { first, second, third })

        {

            var contains = items.Contains(item);

            System.Console.WriteLine("Contains " + item.Name + ": " + contains);

            if (!contains) {

                items.Add(item);

            }

        }

        Console.WriteLine("List Contents:");

        Console.WriteLine(string.Join(", ", items.Select(i => i.Name)));

        Console.WriteLine("");

        items.Clear();

        // Alternative: Checking the "Name" property

        foreach (var item in new[] { first, second, third })

        {

            var contains = items.Any(i => i.Name == item.Name);

            System.Console.WriteLine("Contains " + item.Name + ": " + contains);

            if (!contains) {

                items.Add(item);

            }

        }

        Console.WriteLine("List Contents:");

        Console.WriteLine(string.Join(", ", items.Select(i => i.Name)));

    }

}