A12_获取与清空委托列表|匿名委托|Lambda表达式

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/* * 委托的取值与清空委托列表 *  * **/using System;using System.Collections.Generic;using System.Linq;using System.Text;using System.Threading.Tasks;namespace A12_GetAndCleanDelegateList{    class Demo9    {        private Action actHandler;        public Demo9()        {            actHandler += DelegateMethod1;            actHandler += DelegateMethod2;            actHandler += DelegateMethod3;        }        public void DelegateMethod1()        {            Console.WriteLine("Method DelegateMethod1");        }        public void DelegateMethod2()        {            Console.WriteLine("Method DelegateMethod2");        }        public void DelegateMethod3()        {            Console.WriteLine("Method DelegateMethod3");        }        //取得委托列表        public void Test1()        {            Delegate[] delArray = actHandler.GetInvocationList();            foreach (Delegate item in delArray)            {                item.DynamicInvoke();            }        }        //清空委托列表        public void Test2()        {            while (actHandler!=null)            {                actHandler -= this.actHandler;            }            if (actHandler != null)            {                actHandler.Invoke();            }            else            {                Console.WriteLine("委托列表已经清空");            }        }        //清空委托列表通用算法        public void Test3()        {           Delegate[] delArray = actHandler.GetInvocationList();           for (int i = 0; i < delArray.Length; i++)           {                actHandler -= delArray[i] as Action;           }            if (actHandler != null)            {                actHandler.Invoke();            }            else            {                Console.WriteLine("Demo9:Test3() 委托列表已经清空");            }        }        static void Main1(string[] args)        {            Demo9 obj = new Demo9();            obj.Test1();            //obj.Test2();            obj.Test3();        }    }}

/* * 匿名委托 * 如果一个委托不需要在别处调用，那么使用匿名方法可以减少代码量 * **/using System;using System.Collections.Generic;using System.Linq;using System.Text;using System.Threading.Tasks;namespace A12_GetAndCleanDelegateList{    class Demo10    {        public void Test2()        {            Func<int, int, int> funAddingMethodHandler = delegate (int num1, int num2)            {                return num1 + num2;            };            int result = funAddingMethodHandler(20, 30);            Console.WriteLine(result);        }        static void Main1(string[] args)        {            Demo10 obj = new Demo10();            obj.Test2();        }    }}

/* * Lambda表达式 * 对于匿名委托的进一步简化 * 1.去掉delegate关键字 * 2.去掉参数列表中的类型定义 * 3.如果方法中只有一条语句，可以去掉return和{}; * 4. * **/using System;using System.Collections.Generic;using System.Linq;using System.Text;using System.Threading.Tasks;namespace A12_GetAndCleanDelegateList{    class Demo11    {        public void Test1()        {            //匿名委托            Func<int, int, int> funAddingMethodHandler = delegate (int num1, int num2)            {                return num1 + num2;            };            //Lambda表达式            Func<int, int, int> funAddingMethodHandler2 = (int num1, int num2) =>            {                return num1 + num2;            };            Func<int, int, int> funAddingMethodHandler3 = (num1, num2) =>            {                return num1 + num2;            };            Func<int, int, int> funAddingMethodHandler4 = (num1, num2) => num1 + num2;            //方法中只有一个参数，可以去掉()            Func<int, int> funAddingMethodHandler5 = (num1) => num1 + 888;            Func<int, int> funAddingMethodHandler6 = num1 => num1 + 888;            //如果没有参数            Func<int> funAddingMethodHandler7 = () => 888;            Console.WriteLine(funAddingMethodHandler(10, 20));            Console.WriteLine(funAddingMethodHandler2(80, 20));            Console.WriteLine(funAddingMethodHandler3(80, 30));            Console.WriteLine(funAddingMethodHandler4(80, 40));            Console.WriteLine(funAddingMethodHandler5(200));            Console.WriteLine(funAddingMethodHandler6(20));            Console.WriteLine(funAddingMethodHandler7());        }        //Lambda表达式使用外部变量        public void Test2()        {            int num = 100;            Func<int, int> funHandler = x => x + num; // 其中num表达式外部变量            Console.WriteLine(funHandler(1000));        }        static void Main1(string[] args)        {            Demo11 obj = new Demo11();            obj.Test1();            obj.Test2();        }    }}

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