程式碼Demo

namespace TestCore
{
    public class Program
    {
        public static void Main(string[] args)
        {
            //例項化物件，第一次沒有觸發事件
            EventTest e = new EventTest();
            //例項化接收器物件
            SubscriEvent v = new SubscriEvent();
            //註冊事件
            e.ChangeNum += new
 
 EventTest.NumManipulationHandler(v.printf);
            e.ChangeNum += new EventTest.NumManipulationHandler(v.printN);
            e.SetValue(7);
            e.SetValue(11);
            Console.WriteLine("hello word");
        }
    }

    //釋出器類
    public class EventTest
    {
        private int value;
        
 
//定義委託
        public delegate void NumManipulationHandler();
        //定義事件
        public event NumManipulationHandler ChangeNum;

        protected virtual void OnNumChanged()
        {
            if (ChangeNum != null)
            {
                //事件被觸發
                ChangeNum();
            }
            
 
else {
                Console.WriteLine("event not fire");
            }
        }

        public EventTest()
        {
            int n = 5;
            SetValue(n);
        }

        public void SetValue(int n)
        {
            if (value != n)
            {
                value = n;
                OnNumChanged();
            }
        }
    }

    //訂閱器類
    public class SubscriEvent
    {
        public void printf()
        {
            Console.WriteLine("event fire");
        }
        public void printN()
        {
            Console.WriteLine("事件執行了");
        }
    }
}

執行結果：