using System;

using System.Collections.Generic;

public class Program

{

    public void Main()

    {

        var thing = new Thing

        {

            ThisIsAList = {}

        };

​

        Console.WriteLine(thing.ThisIsAList == null); // prints "True"

    }

    public class Thing

    {

        public List<string> ThisIsAList { get; set; }

    }

}

​

​