ienumrable interface

string[] name = {"kasdf","tops","tech"};

            IEnumerable<string> item = name
                                .Where(a => a.Length == 5)
                                .OrderBy(a => a)
                               .Select(a => a);
            foreach (var data in item)
            {
                DropDownList1.Items.Add(data);
            }
ienumarable is inter face used in enumrable class for create <type> of collection.