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

namespace ConsoleApplication1
{
    class Program
    {
        static void Main(string[] args)
        {
            List<Item> l = new List<Item>()
                               {
                                   new Item("1", "2")
                               };
            Console.WriteLine(l.Contains(new Item("1", "2"))); // True
            Console.WriteLine(l.IndexOf(new Item("1", "2"))); // 0
            Console.Read();
        }
    }

    public class Item
    {
        private string param1;
        private string param2;

        public Item(string p1, string p2)
        {
            this.param1 = p1;
            this.param2 = p2;
        }

        public override bool Equals(object obj)
        {
            return obj is Item
                   && ((Item)obj).param1 == this.param1
                   && ((Item)obj).param2 == this.param2;
        }

        public override int GetHashCode()
        {
            return param1.GetHashCode() ^ param2.GetHashCode();
        }
    }
}