C#委托事件详解第三篇

[来源] 达内    [编辑] 达内   [时间]2012-09-18

这篇博客用委托简单的实现了几个小案列,如:委托实现多线程,最后讲述了匿名方法和委托链。

前言: 这篇博客用委托简单的实现了几个小案列,如:委托实现多线程,最后讲述了匿名方法和委托链。

< ol style="padding-left: 50px; color: rgb(0, 0, 0); font-family: Verdana, Geneva, Arial, Helvetica, sans-serif; font-size: 13px; font-style: normal; font-variant: normal; font-weight: normal; letter-spacing: normal; line-height: 19px; orphans: 2; text-align: -webkit-auto; text-indent: 0px; text-transform: none; white-space: normal; widows: 2; word-spacing: 0px; -webkit-text-size-adjust: auto; -webkit-text-stroke-width: 0px; background-color: rgb(255, 238, 238); ">
  • 委托实现多线程
  • < p align="left" style="font-size: 13px; line-height: 19px; margin: 5px auto; text-indent: 0px; color: rgb(0, 0, 0); font-family: Verdana, Geneva, Arial, Helvetica, sans-serif; font-style: normal; font-variant: normal; font-weight: normal; letter-spacing: normal; orphans: 2; text-transform: none; white-space: normal; widows: 2; word-spacing: 0px; -webkit-text-size-adjust: auto; -webkit-text-stroke-width: 0px; background-color: rgb(255, 238, 238); ">(1)我们经常听到使用多线程,所以多线程执行的是什么?很简单,就是执行方法

    < p align="left" style="font-size: 13px; line-height: 19px; margin: 5px auto; text-indent: 0px; color: rgb(0, 0, 0); font-family: Verdana, Geneva, Arial, Helvetica, sans-serif; font-style: normal; font-variant: normal; font-weight: normal; letter-spacing: normal; orphans: 2; text-transform: none; white-space: normal; widows: 2; word-spacing: 0px; -webkit-text-size-adjust: auto; -webkit-text-stroke-width: 0px; background-color: rgb(255, 238, 238); ">(2)举个例子,完成输出一句I Love YOu,随机的切换红色,蓝色,黄色,白色

    < p align="left" style="font-size: 13px; line-height: 19px; margin: 5px auto; text-indent: 0px; color: rgb(0, 0, 0); font-family: Verdana, Geneva, Arial, Helvetica, sans-serif; font-style: normal; font-variant: normal; font-weight: normal; letter-spacing: normal; orphans: 2; text-transform: none; white-space: normal; widows: 2; word-spacing: 0px; -webkit-text-size-adjust: auto; -webkit-text-stroke-width: 0px; background-color: rgb(255, 238, 238); "> 

    < div style="background-color: rgb(245, 245, 245); font-family: 'Courier New'; font-size: 12px; border: 1px solid rgb(204, 204, 204); padding: 5px; overflow: auto; margin: 5px 0px; color: rgb(0, 0, 0); font-style: normal; font-variant: normal; font-weight: normal; letter-spacing: normal; orphans: 2; text-align: -webkit-auto; text-indent: 0px; text-transform: none; white-space: normal; widows: 2; word-spacing: 0px; -webkit-text-size-adjust: auto; -webkit-text-stroke-width: 0px; " class="cnblogs_code">
     1
       class Program 
     2
    
     
     3    { 
     4
     
     5        static
     void Main(string
    [] args) 
    
     6
     
     7        { 
     8
     
     9            Thread thread=new
     Thread(Red); 10
     
    11            Thread thread1=new
     Thread(Yellow); 12
     
    13            Thread thread2=new
     Thread(Blue); 14
     
    15        //
    在这里我们将Thread转到元数据的话我们就可以看到这是一个委托实现的方法
    
    16 
    17            thread.Start(); 
    18
     
    19            thread1.Start(); 
    20
     
    21            thread2.Start(); 
    22
     
    23        } 
    24
     
    25        public
     static void
     Red() 
    
    26
     
    27        { 
    28
     
    29            for
    (int i=0
    ;i<10000000
    
    ;i++) 30
     
    31            { 
    32
     
    33                Console.ForegroundColor=ConsoleColor.Red; 
    34
     
    35                Console.WriteLine("
    I Love You"
    
    
    ); 36
     
    37                Console.ForegroundColor=ConsoleColor.White; 
    38
     
    39            } 
    40
     
    41        } 
    42
     
    43        public
     static void
     Yellow() 
    
    44
     
    45        { 
    46
     
    47            for
    (int i=0
    ;i<10000000
    
    ;i++) 48
     
    49            { 
    50
     
    51                Console.ForegroundColor=ConsoleColor.Yellow; 
    52
     
    53                Console.WriteLine("
    I Love You"
    
    
    ); 54
     
    55                Console.ForegroundColor=ConsoleColor.White; 
    56
     
    57            } 
    58
     
    59        } 
    60
     
    61        public
     static void
     Blue() 
    
    62
     
    63        {
    65            for
    (int i=0
    ;i<10000000
    
    ;i++)
    
    67            {
    69                Console.ForegroundColor=ConsoleColor.Blue;
    71                Console.WriteLine("
    I Love You"
    );
    
    
    
    73                Console.ForegroundColor=ConsoleColor.White;
    75            }
    77        }
    79    }
    < p style="font-size: 13px; line-height: 19px; margin: 5px auto; text-indent: 0px; color: rgb(0, 0, 0); font-family: Verdana, Geneva, Arial, Helvetica, sans-serif; font-style: normal; font-variant: normal; font-weight: normal; letter-spacing: normal; orphans: 2; text-align: -webkit-auto; text-transform: none; white-space: normal; widows: 2; word-spacing: 0px; -webkit-text-size-adjust: auto; -webkit-text-stroke-width: 0px; background-color: rgb(255, 238, 238); "> 

    < ol style="padding-left: 50px; color: rgb(0, 0, 0); font-family: Verdana, Geneva, Arial, Helvetica, sans-serif; font-size: 13px; font-style: normal; font-variant: normal; font-weight: normal; letter-spacing: normal; line-height: 19px; orphans: 2; text-align: -webkit-auto; text-indent: 0px; text-transform: none; white-space: normal; widows: 2; word-spacing: 0px; -webkit-text-size-adjust: auto; -webkit-text-stroke-width: 0px; background-color: rgb(255, 238, 238); ">
  • 匿名方法和Lambda
  • < p align="left" style="font-size: 13px; line-height: 19px; margin: 5px auto; text-indent: 0px; color: rgb(0, 0, 0); font-family: Verdana, Geneva, Arial, Helvetica, sans-serif; font-style: normal; font-variant: normal; font-weight: normal; letter-spacing: normal; orphans: 2; text-transform: none; white-space: normal; widows: 2; word-spacing: 0px; -webkit-text-size-adjust: auto; -webkit-text-stroke-width: 0px; background-color: rgb(255, 238, 238); ">(1)我们可以定义两个方法,然后实现委托方法的调用,代码如下:

    < p align="left" style="font-size: 13px; line-height: 19px; margin: 5px auto; text-indent: 0px; color: rgb(0, 0, 0); font-family: Verdana, Geneva, Arial, Helvetica, sans-serif; font-style: normal; font-variant: normal; font-weight: normal; letter-spacing: normal; orphans: 2; text-transform: none; white-space: normal; widows: 2; word-spacing: 0px; -webkit-text-size-adjust: auto; -webkit-text-stroke-width: 0px; background-color: rgb(255, 238, 238); ">  

    < div style="background-color: rgb(245, 245, 245); font-family: 'Courier New'; font-size: 12px; border: 1px solid rgb(204, 204, 204); padding: 5px; overflow: auto; margin: 5px 0px; color: rgb(0, 0, 0); font-style: normal; font-variant: normal; font-weight: normal; letter-spacing: normal; orphans: 2; text-align: -webkit-auto; text-indent: 0px; text-transform: none; white-space: normal; widows: 2; word-spacing: 0px; -webkit-text-size-adjust: auto; -webkit-text-stroke-width: 0px; " class="cnblogs_code">
     1
        public delegate
     
    
    void  FuncDelegate();  2
     
     3     class
     Program  4
     
     5     { 
     6
     
     7         static
     void Main(string
    [] args) 
    
     8
     
     9         { 
    10
     
    11             //
    这样我们可以调用第一个方法,
    
    12 
    13             Run(Func); 
    14
     
    15             //
    但是我们如何调用第二个方法了,这时候我们可以使用匿名方法
    
    16 
    17             Run(FuncExt); 
    18
     
    19             Console.ReadKey(); 
    20
     
    21         } 
    22
     
    23  
    24 
    25         public
     static void
     Run(FuncDelegate target) 
    
    26
     
    27         { 
    28
     
    29             target(); 
    30
     
    31         } 
    32
     
    33  
    34 
    35         public
     static void
     Func() 
    
    36
     
    37         { 
    38
     
    39             Console.WriteLine("
    无参数"
    ); 
    
    40
     
    41         } 
    42
     
    43  
    44 
    45         public
     static void
     FuncExt() 
    
    46
     
    47         { 
    48
     
    49             Func(10
    ); 50
     
    51         } 
    52         public
     static
    
     void Func(int
     num) 53
     
    54         { 
    55
     
    56             Console.WriteLine("
    数字{0}"
    
    
    , num); 57
     
    58         } 
    59
     
    60     }
    < p style="font-size: 13px; line-height: 19px; margin: 5px auto; text-indent: 0px; color: rgb(0, 0, 0); font-family: Verdana, Geneva, Arial, Helvetica, sans-serif; font-style: normal; font-variant: normal; font-weight: normal; letter-spacing: normal; orphans: 2; text-align: -webkit-auto; text-transform: none; white-space: normal; widows: 2; word-spacing: 0px; -webkit-text-size-adjust: auto; -webkit-text-stroke-width: 0px; background-color: rgb(255, 238, 238); "> 

    < p align="left" style="font-size: 13px; line-height: 19px; margin: 5px auto; text-indent: 0px; color: rgb(0, 0, 0); font-family: Verdana, Geneva, Arial, Helvetica, sans-serif; font-style: normal; font-variant: normal; font-weight: normal; letter-spacing: normal; orphans: 2; text-transform: none; white-space: normal; widows: 2; word-spacing: 0px; -webkit-text-size-adjust: auto; -webkit-text-stroke-width: 0px; background-color: rgb(255, 238, 238); ">      但是这样有时候考虑方法类型较繁琐,并且有些方法只使用一次就不用了,如果我们单独定义方法和委托不太合理,

    < p align="left" style="font-size: 13px; line-height: 19px; margin: 5px auto; text-indent: 0px; color: rgb(0, 0, 0); font-family: Verdana, Geneva, Arial, Helvetica, sans-serif; font-style: normal; font-variant: normal; font-weight: normal; letter-spacing: normal; orphans: 2; text-transform: none; white-space: normal; widows: 2; word-spacing: 0px; -webkit-text-size-adjust: auto; -webkit-text-stroke-width: 0px; background-color: rgb(255, 238, 238); ">     浪费资源,所以就有了匿名方法,语法是:delegate(){};

    < p align="left" style="font-size: 13px; line-height: 19px; margin: 5px auto; text-indent: 0px; color: rgb(0, 0, 0); font-family: Verdana, Geneva, Arial, Helvetica, sans-serif; font-style: normal; font-variant: normal; font-weight: normal; letter-spacing: normal; orphans: 2; text-transform: none; white-space: normal; widows: 2; word-spacing: 0px; -webkit-text-size-adjust: auto; -webkit-text-stroke-width: 0px; background-color: rgb(255, 238, 238); ">     下面我将上面的方法写成这样:

    < p align="left" style="font-size: 13px; line-height: 19px; margin: 5px auto; text-indent: 0px; color: rgb(0, 0, 0); font-family: Verdana, Geneva, Arial, Helvetica, sans-serif; font-style: normal; font-variant: normal; font-weight: normal; letter-spacing: normal; orphans: 2; text-transform: none; white-space: normal; widows: 2; word-spacing: 0px; -webkit-text-size-adjust: auto; -webkit-text-stroke-width: 0px; background-color: rgb(255, 238, 238); ">    

    < div style="background-color: rgb(245, 245, 245); font-family: 'Courier New'; font-size: 12px; border: 1px solid rgb(204, 204, 204); padding: 5px; overflow: auto; margin: 5px 0px; color: rgb(0, 0, 0); font-style: normal; font-variant: normal; font-weight: normal; letter-spacing: normal; orphans: 2; text-align: -webkit-auto; text-indent: 0px; text-transform: none; white-space: normal; widows: 2; word-spacing: 0px; -webkit-text-size-adjust: auto; -webkit-text-stroke-width: 0px; " class="cnblogs_code">
     1
      class Program 
     2
    
     
     3     { 
     4
     
     5         static
     void Main(string
    [] args) 
    
     6
     
     7         { 
     8
     
     9             //
    定义一个委托变量,实现一个匿名方法
    
    10 
    11             FuncDelegate MyFunc = delegate
    () 12
     
    13             { 
    14
     
    15                 Func(); 
    16
     
    17                 Func(10
    ); 18
     
    19             }; 
    20
     
    21             //
    由于匿名方法比较灵活使用比较方法,但是还是要写很多代码,就借鉴了函数式编程便有了Lambda表达式 
    22
    
     
    23             //
    语法: 参数=>方法体
    
    24 
    25             FuncDelegate myFunc2 = () => { Func(10
    ); }; 26
     
    27             FuncDelegate myFunc3 = () => Func(10
    ); 28
     
    29             Run(MyFunc); 
    30
     
    31             Run(myFunc2); 
    32
     
    33             Run(myFunc3); 
    34
     
    35             Console.ReadKey(); 
    36
     
    37         } 
    38
     
    39         public
     static void
     Run(FuncDelegate target) 
    
    40
     
    41         { 
    42
     
    43             target(); 
    44
     
    45         } 
    46
     
    47         public
     static void
     Func() 
    
    48
     
    49         { 
    50
     
    51             Console.WriteLine("
    无参数"
    ); 
    
    52
     
    53         } 
    54
     
    55         public
     static void
     FuncExt() 
    
    56
     
    57         { 
    58
     
    59             Func(10
    ); 60
     
    61         } 
    62
     
    63         public
     static void
     Func(int
    
     num) 64
     
    65         { 
    66
     
    67             Console.WriteLine("
    数字{0}"
    
    
    , num); 68
     
    69         } 
    70
     
    71     }
    < p align="left" style="font-size: 13px; line-height: 19px; margin: 5px auto; text-indent: 0px; color: rgb(0, 0, 0); font-family: Verdana, Geneva, Arial, Helvetica, sans-serif; font-style: normal; font-variant: normal; font-weight: normal; letter-spacing: normal; orphans: 2; text-transform: none; white-space: normal; widows: 2; word-spacing: 0px; -webkit-text-size-adjust: auto; -webkit-text-stroke-width: 0px; background-color: rgb(255, 238, 238); ">     如果想要学习Lambda表达式的话可以查看MSDN

    < ol style="padding-left: 50px; color: rgb(0, 0, 0); font-family: Verdana, Geneva, Arial, Helvetica, sans-serif; font-size: 13px; font-style: normal; font-variant: normal; font-weight: normal; letter-spacing: normal; line-height: 19px; orphans: 2; text-align: -webkit-auto; text-indent: 0px; text-transform: none; white-space: normal; widows: 2; word-spacing: 0px; -webkit-text-size-adjust: auto; -webkit-text-stroke-width: 0px; background-color: rgb(255, 238, 238); ">
  • 多播委托(委托链)
  • < p align="left" style="font-size: 13px; line-height: 19px; margin: 5px auto; text-indent: 0px; color: rgb(0, 0, 0); font-family: Verdana, Geneva, Arial, Helvetica, sans-serif; font-style: normal; font-variant: normal; font-weight: normal; letter-spacing: normal; orphans: 2; text-transform: none; white-space: normal; widows: 2; word-spacing: 0px; -webkit-text-size-adjust: auto; -webkit-text-stroke-width: 0px; background-color: rgb(255, 238, 238); ">(1)代码解释委托链,详尽的信息都在注释里面了,可以参考一下

    < p align="left" style="font-size: 13px; line-height: 19px; margin: 5px auto; text-indent: 0px; color: rgb(0, 0, 0); font-family: Verdana, Geneva, Arial, Helvetica, sans-serif; font-style: normal; font-variant: normal; font-weight: normal; letter-spacing: normal; orphans: 2; text-transform: none; white-space: normal; widows: 2; word-spacing: 0px; -webkit-text-size-adjust: auto; -webkit-text-stroke-width: 0px; background-color: rgb(255, 238, 238); "> 

    < div style="background-color: rgb(245, 245, 245); font-family: 'Courier New'; font-size: 12px; border: 1px solid rgb(204, 204, 204); padding: 5px; overflow: auto; margin: 5px 0px; color: rgb(0, 0, 0); font-style: normal; font-variant: normal; font-weight: normal; letter-spacing: normal; orphans: 2; text-align: -webkit-auto; text-indent: 0px; text-transform: none; white-space: normal; widows: 2; word-spacing: 0px; -webkit-text-size-adjust: auto; -webkit-text-stroke-width: 0px; " class="cnblogs_code">
    复制代码
     1
       public delegate
     
    
    void FuncDelegate();  2
     
     3     class
     Program  4
     
     5     { 
     6
     
     7         static
     void Main(string
    [] args) 
    
     8
     
     9         { 
    10
     
    11             //
    先定义三个方法,在定义一个委托内心,在定义一个委托变量
    
    12 
    13             FuncDelegate MyFunc; 
    14
     
    15             MyFunc = Func1; 
    16
     
    17             //
    什么事委托链呢?就是使用+=添加委托方法
    
    18 
    19             MyFunc += Func2; 
    20
     
    21             MyFunc += Func3; 
    22
     
    23             //
    当然我们可以通过+=添加方法,所以我们还可以使用-=移除方法
    
    24 
    25             MyFunc -= Func2; 
    26
     
    27             //
    调用委托变量这依次执行所有添加的方法
    
    28 
    29             MyFunc(); 
    30
     
    31            //
    注释:如果在其中一个方法出现异常,其后的方法不再执行
    
    32 
    33             Console.ReadKey(); 
    34
     
    35         } 
    36
     
    37         static
     void Func1() 
    38
    
     
    39         { 
    40
     
    41             Console.WriteLine("
    Func1"
    ); 
    
    42
     
    43         } 
    44
     
    45         static
     void Func2() 
    46
    
     
    47         { 
    48
     
    49             Console.WriteLine("
    Func2"
    ); 
    
    50
     
    51         } 
    52
     
    53         static
     void Func3() 
    54
    
     
    55         { 
    56
     
    57             Console.WriteLine("
    Func3"
    ); 
    
    58
     
    59         } 
    60
     
    61     }
    复制代码
    < p style="font-size: 13px; line-height: 19px; margin: 5px auto; text-indent: 0px; color: rgb(0, 0, 0); font-family: Verdana, Geneva, Arial, Helvetica, sans-serif; font-style: normal; font-variant: normal; font-weight: normal; letter-spacing: normal; orphans: 2; text-align: -webkit-auto; text-transform: none; white-space: normal; widows: 2; word-spacing: 0px; -webkit-text-size-adjust: auto; -webkit-text-stroke-width: 0px; background-color: rgb(255, 238, 238); "> 

    < p align="left" style="font-size: 13px; line-height: 19px; margin: 5px auto; text-indent: 0px; color: rgb(0, 0, 0); font-family: Verdana, Geneva, Arial, Helvetica, sans-serif; font-style: normal; font-variant: normal; font-weight: normal; letter-spacing: normal; orphans: 2; text-transform: none; white-space: normal; widows: 2; word-spacing: 0px; -webkit-text-size-adjust: auto; -webkit-text-stroke-width: 0px; background-color: rgb(255, 238, 238); ">    (2)委托链中添加的方法如果带有返回值,调用委托变量后也会有一个返回值,这个返回值是最后一个方法

    < p align="left" style="font-size: 13px; line-height: 19px; margin: 5px auto; text-indent: 0px; color: rgb(0, 0, 0); font-family: Verdana, Geneva, Arial, Helvetica, sans-serif; font-style: normal; font-variant: normal; font-weight: normal; letter-spacing: normal; orphans: 2; text-transform: none; white-space: normal; widows: 2; word-spacing: 0px; -webkit-text-size-adjust: auto; -webkit-text-stroke-width: 0px; background-color: rgb(255, 238, 238); ">   

    < div style="background-color: rgb(245, 245, 245); font-family: 'Courier New'; font-size: 12px; border: 1px solid rgb(204, 204, 204); padding: 5px; overflow: auto; margin: 5px 0px; color: rgb(0, 0, 0); font-style: normal; font-variant: normal; font-weight: normal; letter-spacing: normal; orphans: 2; text-align: -webkit-auto; text-indent: 0px; text-transform: none; white-space: normal; widows: 2; word-spacing: 0px; -webkit-text-size-adjust: auto; -webkit-text-stroke-width: 0px; " class="cnblogs_code">
    复制代码
     1
     public delegate
     int
    
     FuncIntDelegate();
    
     3     class
     Program
    
     5     {
     7         static
     void Main(string
    [] args)
    
    
     9         {
    11             FuncIntDelegate MyFunc = FuncInt1;
    13             MyFunc += FuncInt1;
    15             MyFunc += FuncInt2;
    17             MyFunc += FuncInt3;
    19             int
     res = MyFunc();
    
    21             //
    如果需要返回其中所有方法的返回值,需要使用循环遍历方法的数组
    
    25             Delegate[] ds = MyFunc.GetInvocationList();  //
    返回一个Delegate[]数组
    
    27             for
     (int i = 0
    ; i < ds.Length; i++)
    
    
    29             {
    31                 FuncIntDelegate temp = (FuncIntDelegate)ds[i];
    33                 Console.WriteLine(temp());
    35             }
    39             Console.WriteLine(res);
    41             Console.ReadKey();
    43         }
    45         static
     int FuncInt1()
    
    47         {
    49             return
     1;
    
    51         }
    53         static
     int FuncInt2()
    
    55         {
    57             return
     2;
    
    59         }
    61         static
     int FuncInt3()
    
    63         {
    65             return
     3;
    
    67         }
    69     }
    复制代码

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