public class Father
    {
        public virtual void Say()
        {
            Console.WriteLine("Father Say");
        }
    }
    public class Son : Father
    {
        public override void Say()
        {
            base.Say();
            Console.WriteLine("Son Say");
        }
    }

        public class Father
        {
            public string Name { get; set; }
            public Father()
            {
                Name = "Father";
            }
        }

        public class Son : Father
        {
            public Son()
                : base()
            {
            }
        }