public delegate void catMiaoHanler(Cat cat);    public class Cat    {        public catMiaoHanler thisHanler;        public string Name { get; set; }        public Cat() { }        public void Miao()        {            Console.WriteLine("miao miao miao ");            thisHanler(this);        }    }    class Mouse    {        public string Name { get; set; }        public int Level { get; set; }        public Mouse(Cat listenCat)        {            listenCat.thisHanler += (cat) =>            {                if (Level > 10) Console.WriteLine(cat.Name + "is coming!!!" + this.Name + " go go go ");                else                    Console.WriteLine(cat.Name + "is coming!!!" + this.Name + " is dead!");            };        }    }    class Program    {        static void Main(string[] args)        {            //Cat cat = new Cat(new List<Mouse> { new Mouse { Name = "tom", Level = 1 }, new Mouse { Name = "jack", Level = 2 } });            Cat cat = new Cat { Name = "Tim" };            Mouse m1 = new Mouse(cat) { Name = "tom", Level = 9 };            Mouse m2 = new Mouse(cat) { Name = "tom2", Level = 19 };            cat.Miao();            Console.ReadLine();        }    }