namespace NullableTest
{
    class MainClass
    {
        public static void Main (string[] args)
        {
            var test = new Test();
            test.Property1 = 20;
            Console.WriteLine(test.Property1.Value);
            Console.ReadLine();
        }
    }

    class Test
    {
        public int? Property1 { get;    set; }
    }
}