C＃观察者的超简单示例/可与委托人一起观察

观察者模式通常通过事件来实现。

这是一个例子：

using System;class Observable{    public event EventHandler SomethingHappened;    public void DoSomething() =>        SomethingHappened?.Invoke(this, EventArgs.Empty);}class Observer{    public void HandleEvent(object sender, EventArgs args)    {        Console.WriteLine("Something happened to " + sender);    }}class Test{    static void Main()    {        Observable observable = new Observable();        Observer observer = new Observer();        observable.SomethingHappened += observer.HandleEvent;        observable.DoSomething();    }}

有关更多详细信息，请参见链接的文章。

请注意，以上示例使用C＃6 空条件
运算符

DoSomething

SomethingHappened

public void DoSomething(){    var handler = SomethingHappened;    if (handler != null)    {        handler(this, EventArgs.Empty);    }}