关于Delegate与接口回调的例子

在C#中用Delegate和接口的回调都能实现外部方法的委托调用，它们有什么区别呢？

Delegate可以用+=或-=快速的绑定或解绑多个方法。而接口实现起来则显得更麻烦。

如果Delegate只绑定一个事件，接口中也只定义了一个方法则两者是等价的。

Delegate例子：

namespace Test
{
    class Program
    {
        static void Main(string[] args)
        {
            CarDelegate car = new CarDelegate();
            car.ColorEvent += new CarDelegate.ColorHandler(ColorMethod1);
            car.ColorEvent += new CarDelegate.ColorHandler(ColorMethod2);
            car.Color = "Black";//修改Color时会触发事件

            Console.ReadLine();
        }

        static void ColorMethod1(string color)
        {
            Console.WriteLine("method1=" + color);
        }

        static void ColorMethod2(string color)
        {
            Console.WriteLine("method2=" + color);
        }
    }

    public class CarDelegate
    {
        private string color;
        public delegate void ColorHandler(string color);
        public event ColorHandler ColorEvent;

        public string Color
        {
            get { return color; }
            set
            {
                color = value;
                ColorEvent(this.color);
            }
        }
    }
}

 关于接口回调的例子：

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;

namespace Test
{
    class Program
    {
        static void Main(string[] args)
        {
            Car car = new Car(new CarActionImpl());
            car.Color = "Black";

            Console.ReadLine();
        }
    }

    public interface ICarAction
    {
        void ChangeColor(string color);
    }

    public class CarActionImpl : ICarAction
    {
        public void ChangeColor(string color)
        {
            Console.WriteLine("method1=" + color);
        }
    }

    public class Car
    {
        private string color;
        private ICarAction carAction;
        public Car(ICarAction carAction)
        {
            this.carAction = carAction;
        }
        public string Color
        {
            get { return color; }
            set
            {
                color = value;
                carAction.ChangeColor(this.color);
            }
        }
    }
}