《C#高级编程》事件的示例代码

运行结果：

Program.cs

using System;

namespace Wrox.ProCSharp.Delegates
{
    class Program
    {
        static void Main()
        {
            var dealer = new CarDealer();

            var michael = new Consumer("Michael");
            dealer.NewCarInfo += michael.NewCarIsHere;

            dealer.NewCar("Mercedes");

            var nick = new Consumer("Nick");
            dealer.NewCarInfo += nick.NewCarIsHere;

            dealer.NewCar("Ferrari");

            dealer.NewCarInfo -= michael.NewCarIsHere;

            dealer.NewCar("Toyota");

            Console.Read();
        }
    }
}

CarDealer.cs

using System;

namespace Wrox.ProCSharp.Delegates
{
    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("CarDealer, new car {0}", car);
            if (NewCarInfo != null)
            {
                NewCarInfo(this, new CarInfoEventArgs(car));
            }
        }
    }
}

Consumer.cs

using System;

namespace Wrox.ProCSharp.Delegates
{
    public class Consumer
    {
        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);
        }
    }
}