事件、委托的定义与使用示例

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

namespace Test
{
    class Start
    {
        public static void Main()
        {
            Tool.Fan fan = new Tool.Fan();
            fan.Rotating += new Tool.RotatingEventHander(fan_Rotating);
            fan.PowerOn();
        }

        static void fan_Rotating(object sender, Tool.RotatingEventArgs e)
        {
            Tool.Fan fan = (Tool.Fan)sender;
            Console.WriteLine("The brand name of this product: {0}.
Place of production: {1}.",fan.BrandName,fan.PlaceOfProduction);
            Console.Write("
");
            Console.WriteLine("This fan is power on now.");
            Console.WriteLine("Current speed is {0}
Current power is {1}.", e.Speed, e.Power);
            Console.Write("
");
            e.Cancel = true;
            Console.WriteLine("This fan is power off now.");
            Console.WriteLine("Current speed is {0}.
Current power is {1}.", e.Speed, e.Power);
            Console.ReadKey();
        }
    }
}

namespace Tool
{
    public class RotatingEventArgs : EventArgs //监视对象转动中的一些数据
    {
        private int _speed;//转速
        public int Speed
        {
            get
            {
                return _speed;
            }
        }
        private int _power;//功率
        public int Power
        {
            get
            {
                return _power;
            }
        }
        private bool _cancel = false;//是否取消该转动
        public bool Cancel
        {
            set
            {
                _cancel = value;
                if (_cancel == true)
                {
                    _speed = 0;
                    _power = 0;
                }
            }
            get
            {
                return _cancel;
            }
        }
        public RotatingEventArgs() //构造函数
        {
            _speed = 2300;
            _power = 5;
        }
    }

    //定义委托
    public delegate void RotatingEventHander(object sender, RotatingEventArgs e);
    public class Fan //监视对象
    {
        //定义事件
        public event RotatingEventHander Rotating;

        protected virtual void OnRotating(RotatingEventArgs e)
        {
            if (Rotating != null)//事件方法注册
            {
                Rotating(this, e);
            }
        }
        public void PowerOn()
        {
            RotatingEventArgs e = new RotatingEventArgs();
            OnRotating(e);
        }
        public readonly String BrandName = "CNC";
        public readonly string PlaceOfProduction = "Guangzhou,China";
    }
}