public class IndexTempte

    {

        public ArrayList nameList = new ArrayList();

        public string this[int index]

        {

            get

            {

                return nameList[index].ToString();

            }

            set { nameList.Add(value); }

        }

    }

        static void Main(string[] args)

        {

            var list = new IndexTempte();

            list[] = "China";

            list[] = "USA";

            list[] = "Germany";

            Console.WriteLine("name :{0}", list[]);

        }