public class Person

    {

        public string Name { get; set; }

        public int Age { get; set; }

    }

    public class PersonCollecton : List<Person>

    {

        public Person this[string name]

        {

            get

            {

                for (int i = ; i < this.Count; i++)

                {

                    if (this[i].Name == name) return this[i];

                }

                return null;

            }

        }

    }

  public calss Test

  {

      static void Main()

      {

          PersonCollection persons = new PersonCollection();

          persons.Add(new Person(){Name = "Li Lei", Age = };

          persons.Add(new Person(){Name = "Han Meimei", Age = };

          Person HanMeimei = persons["Han Meimei"];

     }

}