using System;

using System.Linq;

using System.Collections.Generic;

​

public class Program

{

    public static void Main()

    {

        var test = new Test();

        test.TestList = null;

        test.TestList.OrderByDescending(x=>x.Val);

        Console.WriteLine(test);

    }

    public class Test{

        public Test(){

        TestList= new List<TestVersion>();

        }

        public List<TestVersion> TestList {get;set;} 

    }

    public class TestVersion{

        public string Val {get;set;}

    }

}