委託的學習筆記-不完整

需要再複習 注意： 難精通+易使用+功能強大東西，一旦被濫用後果非常嚴重
缺點1：這是一種方法級別緊耦合，顯示工作中要慎之又慎
缺點2：使可讀性下降，debug的難度增加
缺點3：把委託回調、異步調用和多線程糾纏在一起，會讓代碼變得難以閱讀和維護
缺點4：委託使用不當有可能造成內存泄漏和程序性能下降

多播委託–同步調用
安裝封裝方法的先後順序執行

class Program
    {
        static void Main(string[] args)
        {
            Student stu1 = new Student() { ID = 1, PenColor = ConsoleColor.Red };
            Student stu2 = new Student() { ID = 2, PenColor = ConsoleColor.Green };
            Student stu3 = new Student() { ID = 3, PenColor = ConsoleColor.Yellow };
  

            Action action1 = new Action(stu1.DoHomework);
            Action action2 = new Action(stu2.DoHomework);
            Action action3 = new Action(stu3.DoHomework);


            action1();
            action1.Invoke();
            action2();
            action2.Invoke();
            action3();
            action3.Invoke();

            action1 += action2;
            action1 += action3;

            action1.Invoke();

        }
    }

    class Student
    {
        public int ID { get; set; }
        public ConsoleColor PenColor { get; set; }

        public void DoHomework()
        {
            for (int i = 0; i < 5; i++)
            {
                Console.ForegroundColor = this.PenColor;
                Console.WriteLine("Student{0} doing homework{1}",this.ID,i);
                //睡眠1秒鐘
                Thread.Sleep(1000);
            }
        }
    }

串行同步單線程
並行異步多線程

隱式異步調用

 class Program
    {
        static void Main(string[] args)
        {
            Student stu1 = new Student() { ID = 1, PenColor = ConsoleColor.Red };
            Student stu2 = new Student() { ID = 2, PenColor = ConsoleColor.Green };
            Student stu3 = new Student() { ID = 3, PenColor = ConsoleColor.Yellow };
  

            Action action1 = new Action(stu1.DoHomework);
            Action action2 = new Action(stu2.DoHomework);
            Action action3 = new Action(stu3.DoHomework);


            action1.BeginInvoke(null,null);
            action2.BeginInvoke(null, null);
            action3.BeginInvoke(null, null);

            for (int i = 0; i < 10; i++)
            {
                Console.ForegroundColor = ConsoleColor.Cyan;
                Console.WriteLine("Main thread{0}",i);
                Thread.Sleep(1000);
            }
        }
    }

    class Student
    {
        public int ID { get; set; }
        public ConsoleColor PenColor { get; set; }

        public void DoHomework()
        {
            for (int i = 0; i < 5; i++)
            {
                Console.ForegroundColor = this.PenColor;
                Console.WriteLine("Student{0} doing homework{1}",this.ID,i);
                //睡眠1秒鐘
                Thread.Sleep(1000);
            }
        }
    }

顯式異步調用

誰都不等誰，還會爭搶資源

class Program
    {
        static void Main(string[] args)
        {
            Student stu1 = new Student() { ID = 1, PenColor = ConsoleColor.Red };
            Student stu2 = new Student() { ID = 2, PenColor = ConsoleColor.Green };
            Student stu3 = new Student() { ID = 3, PenColor = ConsoleColor.Yellow };

            Thread thread1 = new Thread(new ThreadStart(stu1.DoHomework));
            Thread thread2= new Thread(new ThreadStart(stu2.DoHomework));
            Thread thread3 = new Thread(new ThreadStart(stu3.DoHomework));

            thread1.Start();
            thread2.Start();
            thread3.Start();

            for (int i = 0; i < 10; i++)
            {
                Console.ForegroundColor = ConsoleColor.Cyan;
                Console.WriteLine("Main thread{0}",i);
                Thread.Sleep(1000);
            }
        }
    }

    class Student
    {
        public int ID { get; set; }
        public ConsoleColor PenColor { get; set; }

        public void DoHomework()
        {
            for (int i = 0; i < 5; i++)
            {
                Console.ForegroundColor = this.PenColor;
                Console.WriteLine("Student{0} doing homework{1}",this.ID,i);
                //睡眠1秒鐘
                Thread.Sleep(1000);
            }
        }
    }