Delegate&Event

Delegate

1.基本类：

     public class Student
     {
         public int Id { get; set; }
         public string Name { get; set; }
 
         public void Study()
         {
             Console.WriteLine("学习.net高级班公开课");
         }
 
         public void StudyAdvanced(string name)
         {
             Console.WriteLine("学习.net高级班公开课");
         }
 
         public static void Show()
         {
             Console.WriteLine(");
         }
     }

Student

2. 声明委托

         public delegate void NoReturnNoPara();
         public delegate void NoReturnWithPara(int x, int y);
         public delegate int WithReturnNoPara();
         public delegate string WithReturnWithPara(int x, int y);    

3. =+ 的方法

         private void DoNothing()
         {
             Console.WriteLine("这里是DoNothing");
         }
 
         private static void DoNothingStatic()
         {
             Console.WriteLine("这里是DoNothing");
         }
 
         private void ShowPlus(int x, int y)
         {
             Console.WriteLine("ShowPlus x={0} y={1} x+y={2}", x, y, x + y);
         }
 
         private static void ShowPlusStatic(int x, int y)
         {
             Console.WriteLine("ShowPlusStatic x={0} y={1} x+y={2}", x, y, x + y);
         }    

4.委托三部曲

声明(在上面)+实例化+调用

            {
                 NoReturnNoPara method = new NoReturnNoPara(this.DoNothing);//2 委托的实例化
                 method.Invoke();//3 委托调用
                 method();//另一种调用方式
                 //method.BeginInvoke(null, null);//异步调用
                 this.DoNothing();//直接调用对应的方法，效果一样
             }    

5.多播委托

          {
                 NoReturnNoPara method = new NoReturnNoPara(MyDelegate.DoNothingStatic);
                 method += student.Study;
                 method -= student2.Study;
                 method += this.DoNothing;
                 method += student.Study;
                 method += Student.Show;
                 method += () => Console.WriteLine("这里lambda");
                 method.Invoke();
                 //method.BeginInvoke(null,null);//多播委托不能异步
                 method -= MyDelegate.DoNothingStatic;
                 method -= MyDelegate.DoNothingStatic;
                 method -= this.DoNothing;
                 method -= student.Study;
                 method -= Student.Show;
                 method -= () => Console.WriteLine("这里lambda");
 
                 //委托里面lambda表达式之后加入的方法都无效了？
                 method.Invoke();
             }
             {
                 NoReturnNoPara method = new NoReturnNoPara(student.Study);
                 method.Invoke();
             }
             {
                 NoReturnNoPara method = new NoReturnNoPara(Student.Show);
                 method.Invoke();
             }
             {
                 NoReturnWithPara method = new NoReturnWithPara(ShowPlus);
                 method += ShowPlus;
                 method += ShowPlus;
                 method += ShowPlus;
                 method -= ShowPlus;
                 method -= ShowPlus;
                 method(, );
             }    

Event

    public class Baby
     {
         public void Cry()
         {
             Console.WriteLine("{0} Cry", this.GetType().Name);
         }
     }

Baby

      public class Brother
     {
         public void Turn()
         {
             Console.WriteLine("{0} Turn", this.GetType().Name);
         }
     }

Brother

     public class Dog
     {
         public void Wang()
         {
             Console.WriteLine("{0} Wang", this.GetType().Name);
         }
     }

Dog

     public class Father
     {
         public void Shout()
         {
             Console.WriteLine("{0} Shout", this.GetType().Name);
         }
     }

Father

     public class Mother
     {
         public void Wispher()
         {
             Console.WriteLine("{0} Wispher", this.GetType().Name);
         }
     }

Mother

     public class Mouse
     {
         public void Run()
         {
             Console.WriteLine("{0} Run", this.GetType().Name);
         }
     }

Mouse

     public class Neighbor
     {
         public void Awake()
         {
             Console.WriteLine("{0} Awake", this.GetType().Name);
         }
     }

Neighbor

     public class Stealer
     {
         public void Hide()
         {
             Console.WriteLine("{0} Hide", this.GetType().Name);
         }
     }

Stealer

　　　　　　　　　　　　　　　　　　　　　　　　　　　　　　发布

     /// <summary>
     /// 发布者
     /// 一只猫，miao一声
     /// 导致一系列的触发动作
     /// </summary>
     public class Cat
     {
         public void Miao()
         {
             Console.WriteLine("{0} Miao", this.GetType().Name);
             new Neighbor().Awake();
             new Mouse().Run();
             new Dog().Wang();
             new Baby().Cry();
             new Mother().Wispher();
             new Brother().Turn();
             new Father().Shout();
         }
 
         public Action MiaoAction;//委托的实例
         public event Action MiaoActionEvent;//事件是 委托的实例，加了event关键字-----发布者
         //event做了权限控制，保证外部不能赋值和调用
         public void MiaoDelegate()
         {
             Console.WriteLine("{0} MiaoDelegate", this.GetType().Name);
 
             MiaoAction.Invoke();
         }
 
         public void MiaoEvent()
         {
             Console.WriteLine("{0} MiaoEvent", this.GetType().Name);
             if (MiaoActionEvent != null)
             {
                 //MiaoActionEvent.Invoke();
                 //MiaoActionEvent();
                 foreach (Action item in MiaoActionEvent.GetInvocationList())//触发
                 {
                     Console.WriteLine("*********");
                     item.Invoke();
                     //item.BeginInvoke(null,null);
                 }
             }
         }
     }

订阅:

 　　　　　　　　　　{
                     Console.WriteLine("*******Miao******");
                     Cat cat = new Cat();
                     cat.Miao();
 
                     Console.WriteLine("*******MiaoDelegate******");
                     //cat.MiaoAction += new Neighbor().Awake;
 
                     cat.MiaoAction += new Mouse().Run;
                     cat.MiaoAction -= new Mouse().Run;
                     cat.MiaoAction += new Baby().Cry;
                     cat.MiaoAction += new Mother().Wispher;
 
                     cat.MiaoAction.Invoke();
                     cat.MiaoAction = null;
 
                     cat.MiaoAction += new Brother().Turn;
                     cat.MiaoAction += new Father().Shout;
                     cat.MiaoAction += new Dog().Wang;
 
                     cat.MiaoDelegate();
 
                     Console.WriteLine("*******MiaoEvent******");
                     cat.MiaoActionEvent += new Neighbor().Awake;
                     cat.MiaoActionEvent += new Mouse().Run;
                     cat.MiaoActionEvent += new Baby().Cry;
 
                     //cat.MiaoActionEvent.Invoke();
                     //cat.MiaoActionEvent = null;
 
                     cat.MiaoActionEvent += new Mother().Wispher;
                     cat.MiaoActionEvent += new Brother().Turn;
                     cat.MiaoActionEvent += new Father().Shout;
                     cat.MiaoActionEvent += new Dog().Wang;
                     cat.MiaoEvent();
                 }