5. 第二章：C#委托和事件

 1     public class MyTestClass
 2     {
 3         //定义委托
 4         public delegate void MyDelegateHandler(string param);
 5 
 6         //构造函数
 7         public MyTestClass()
 8         {
 9             this.MyDelegateHappened += this.MyInsideDelegateMethod;
10         }
11 
12         //内部方法
13         private void MyInsideDelegateMethod(string param)
14         {
15             Console.WriteLine("I am running inside the class \"MyClass\" -> void MyInsideDelegateMethod(string param)");
16             Console.WriteLine(param);
17         }
18 
19         //执行
20         public void Execute(string param)
21         {
22             this.OnMyDeletateHappened(param);
23         }
24 
25         //事件
26         public event MyDelegateHandler MyDelegateHappened;
27         protected virtual void OnMyDeletateHappened(string param)
28         {
29             MyDelegateHandler handler = this.MyDelegateHappened;
30             if (handler != null)
31             {
32                 handler(param);
33             }
34         }
35     }

 1         static void Main(string[] args)
 2         {
 3             Console.WriteLine("Only the inside method will be executed!");
 4             //实例化
 5             MyTestClass myTestClass = new MyTestClass();
 6             myTestClass.Execute("Hello, world!");
 7             Console.WriteLine();
 8 
 9             Console.WriteLine("The outside method will be added to the delegate logic!");
10             //新增外部委托的方法
11             myTestClass.MyDelegateHappened += MyOutsideDelegateMethod;
12             myTestClass.Execute("Hello, world!");
13             Console.WriteLine();
14 
15             Console.WriteLine("The outside method will be removed from the delegate logic!");
16             //去除外部委托的方法
17             myTestClass.MyDelegateHappened -= MyOutsideDelegateMethod;
18             myTestClass.Execute("Hello, world!");
19             Console.ReadLine();
20         }
21 
22         private static void MyOutsideDelegateMethod(string param)
23         {
24             Console.WriteLine("I am running ouside the class \"Program\" -> void MyOutsideDelegateMethod(string param)");
25             Console.WriteLine(param);
26         }

        public event EventHandler MyEventHappened;
        protected virtual void OnMyEventHanppened()
        {
            EventHandler handler = this.MyEventHappened;
            if (handler != null)
            {
                handler(this, EventArgs.Empty);
            }
        }

 1 #region Assembly mscorlib.dll, v4.0.0.0
 2 // C:\Program Files (x86)\Reference Assemblies\Microsoft\Framework\.NETFramework\v4.5\mscorlib.dll
 3 #endregion
 4 
 5 using System.Runtime.InteropServices;
 6 
 7 namespace System
 8 {
 9     // Summary:
10     //     Represents the method that will handle an event that has no event data.
11     //
12     // Parameters:
13     //   sender:
14     //     The source of the event.
15     //
16     //   e:
17     //     An System.EventArgs that contains no event data.
18     [Serializable]
19     [ComVisible(true)]
20     public delegate void EventHandler(object sender, EventArgs e);
21 }

        public event EventHandler<EventArgs> MyEventHappened;
        protected virtual void OnMyEventHanppened(EventArgs args)
        {
            EventHandler<EventArgs> handler = this.MyEventHappened;
            if (handler != null)
            {
                handler(this, args);
            }
        }

 1 #region Assembly mscorlib.dll, v4.0.0.0
 2 // C:\Program Files (x86)\Reference Assemblies\Microsoft\Framework\.NETFramework\v4.5\mscorlib.dll
 3 #endregion
 4 
 5 namespace System
 6 {
 7     // Summary:
 8     //     Represents the method that will handle an event.
 9     //
10     // Parameters:
11     //   sender:
12     //     The source of the event.
13     //
14     //   e:
15     //     An System.EventArgs that contains the event data.
16     //
17     // Type parameters:
18     //   TEventArgs:
19     //     The type of the event data generated by the event.
20     [Serializable]
21     public delegate void EventHandler<TEventArgs>(object sender, TEventArgs e);
22 }

 1     public class MyEventArgs : EventArgs
 2     {
 3         private string _param;
 4 
 5         public MyEventArgs(string param)
 6         {
 7             this._param = param;
 8         }
 9 
10         public string Param
11         {
12             get { return this._param; }
13         }
14     }

1         public event EventHandler<MyEventArgs> MyEventHappened2;
2         protected virtual void OnMyEventHappened2(MyEventArgs args)
3         {
4             EventHandler<MyEventArgs> handler = this.MyEventHappened2;
5             if (handler != null)
6             {
7                 handler(this, args);
8             }
9         }

 1     public class MyTestClass2 {
 2         public void Execute(string param)
 3         {
 4             this.OnMyEventHappened(new MyEventArgs(param));
 5         }
 6 
 7         public event EventHandler<MyEventArgs> MyEventHappened;
 8         protected virtual void OnMyEventHappened(MyEventArgs args)
 9         {
10             EventHandler<MyEventArgs> handler = this.MyEventHappened;
11             if (handler != null)
12             {
13                 handler(this, args);
14             }
15         }
16     }
17 
18     public class MyEventArgs : EventArgs
19     {
20         private string _param;
21 
22         public MyEventArgs(string param)
23         {
24             this._param = param;
25         }
26 
27         public string Param
28         {
29             get { return this._param; }
30         }
31     }

 1         static void Main(string[] args)
 2         {
 3             MyTestClass2 myTestClass = new MyTestClass2();
 4             myTestClass.MyEventHappened += MyTestClass_MyEventHappened;
 5             myTestClass.Execute("Hi~");
 6 
 7             Console.ReadLine();
 8         }
 9 
10         private static void MyTestClass_MyEventHappened(object sender, MyEventArgs e)
11         {
12             Console.WriteLine(e.Param);
13         }