Action<T> Delegate 使用

1. new Action(()=>{})

2. (Action)(()=>{})

3.

public void show(){Action<String> messageAction;messageAction=ShowMessage;messageAction("HelloWorld!");}private void showMessage(String message){Console.WriteLine(message);}

4.

public void show(){Action<String> messageAction;messageAction=delegate (String s){ShowMessage(s)};messageAction("HelloWorld!");}private void showMessage(String message){Console.WriteLine(message);}

So we can treat Action as a method delegate with one parameter and no return value.

when declare an event, we can use like:

      public event Action<String> messageArriveEvent;

      messageArrive+=new Action(()=>{});