public ActionResult Index()
        {
            IEnumerable <Person> people;
            string filter = (string)this.Session["FilterString"];

            if (filter != null && filter != "")
            {
                bool caseSensitive = (bool)this.Session["FilterCaseSensitive"];
                people = PersonList.Filter(filter, caseSensitive, PersonList.people);
            }
            else
            {
                people = from person in PersonList.people
                         select person;
            }
            if (this.Session["SortByName"] != null)
            {
                people = PersonList.Sort((bool)this.Session["SortByName"], people);
            }
            return(View(people));
        }