C#事件弱事件类型

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Windows;
namespace Event
{
    //windowsBase dll
    class Program
    {
        static void Main(string[] args)
        {
            var dealer = new CarDealer();

            var michael = new Consumer("Michael呵呵1");

            WeakCarInfoEventManager.AddListener(dealer, michael);

            dealer.NewCar("Mercedes");

            var nick = new Consumer("Nick2哈哈");
            WeakCarInfoEventManager.AddListener(dealer, nick);
            dealer.NewCar("Ferrari");
            
            WeakCarInfoEventManager.RemoveListener(dealer, michael);
            //dealer.NewCar("Toyota");
            Console.ReadKey();
        }
    }
    public class CarInfoEventArgs : EventArgs
    {
        public CarInfoEventArgs(string car)
        {
            this.car = car;
        }
        public string car { get; private set; }
    }


    public class CarDealer
    {

        public event EventHandler<CarInfoEventArgs> NewCarInfo;
        public void NewCar(string car)
        {
            Console.WriteLine("new car111 {0}", car);
            if (NewCarInfo != null)
            {
                NewCarInfo(this, new CarInfoEventArgs(car));
            }
        }
    }

    public class WeakCarInfoEventManager : WeakEventManager
    {
        public static WeakCarInfoEventManager CurrentManager
        {
            get
            {
                WeakCarInfoEventManager manager = GetCurrentManager(typeof(WeakCarInfoEventManager))
                    as WeakCarInfoEventManager;
                if (manager == null)
                {
                    manager = new WeakCarInfoEventManager();
                    SetCurrentManager(typeof(WeakCarInfoEventManager), manager);
                }
                return manager;
            }
        }
        public static void AddListener(object source, IWeakEventListener listener)
        {
            CurrentManager.ProtectedAddListener(source, listener);
        }
        public static void RemoveListener(object source, IWeakEventListener listener)
        {
            CurrentManager.ProtectedRemoveListener(source, listener);
        }
        protected override void StartListening(object source)
        {
            (source as CarDealer).NewCarInfo += CarDealer_NewCarInfo;
        }
        void CarDealer_NewCarInfo(object sender, CarInfoEventArgs e)
        {
            DeliverEvent(sender, e);
        }
        protected override void StopListening(object source)
        {
            (source as CarDealer).NewCarInfo -= CarDealer_NewCarInfo;
        }

    }

    public class Consumer : IWeakEventListener
    {
        private string name;
        public Consumer(string name)
        {
            this.name = name;
        }
        public void NewCarIsHere(object sender, CarInfoEventArgs e)
        {
            Console.WriteLine("{0}:car{1} is new", name, e.car);
        }
        bool IWeakEventListener.ReceiveWeakEvent(Type managerType, object sender, EventArgs e)
        {
            NewCarIsHere(sender, e as CarInfoEventArgs);
            return true;
        }
    }

    public class Consumer2 : IWeakEventListener
    {
       private string name;
       public Consumer2(string name)
        {
            this.name = name;
        }
        public void NewCarIsHere(object sender, CarInfoEventArgs e)
        {
            Console.WriteLine("2222{0}:car{1} is new", name, e.car);
        }
        bool IWeakEventListener.ReceiveWeakEvent(Type managerType, object sender, EventArgs e)
        {
            NewCarIsHere(sender, e as CarInfoEventArgs);
            return true;
        }
    }

}