using System;

using System.Collections.Generic;

using System.Linq;

​

​

public class Program

{

    public static void Main()

    {

        var list = new List<string> { "test", "test", "aaaaa", "bbbbbbb", "cccccccc"};

        var ordered = list.OrderBy(x => x).Distinct();

        foreach(var item in ordered){

            Console.WriteLine(item);

        }

    }

}