委托既可以封装一个方法，又可以对同一类型的方法进行封装，它就是多播委托

1 using System; 2 using System.Collections.Generic; 3 using System.Linq; 4 using System.Text; 5  6 namespace DelegateTest 7 { 8     class Program 9     {10         //申明一个委托类型，它的实例引用一个方法11         //该方法传递0参数，返回void类型12         public delegate string DelegateTestOne();13 14         static void Main(string[] args)15         {16             //用静态方法来实例化委托17             DelegateTestOne teststatic = new DelegateTestOne(Program.method1);18 19             //用实例方法来实例化委托20             DelegateTestOne test2 = new DelegateTestOne(new Program().method2);21 22             //用实例方法来实例化委托23             DelegateTestOne test3 = new DelegateTestOne(new Program().method3);24 25             //定义空一个委托对象26             DelegateTestOne deleteAll = null;27             deleteAll += teststatic;28             deleteAll += test2;29             deleteAll += test3;30             Console.WriteLine(Test(deleteAll));31 32             Console.ReadLine();33         }34 35 36         public static string method1()37         {38 39             //Console.WriteLine("这是一个静态方法");40             return "这是一个静态方法";41         }42 43         public string method2()44         {45             //Console.WriteLine("这是实例方法2");46             return "这是实例方法2";47         }48 49         public string method3()50         {51            // Console.WriteLine("这是实例方法3");52             return "这是实例方法3";53         }54 55 56         //测试多播委托57         public static string Test(DelegateTestOne testone)58         {59             if (testone == null)60             {61                 return null;62             }63             StringBuilder returnstring = new StringBuilder();64 65             Delegate[] delegatearray = testone.GetInvocationList();66 67             foreach (DelegateTestOne t in delegatearray)68             {69                 try70                 {71                     returnstring.Append(t() + Environment.NewLine);72                 }73                 catch (Exception e)74                 {75 76                 }77             }78             //把结果返回给调用者79             return returnstring.ToString();80         }81 82     }83 }

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