C＃观察者/观察者与代表的超简单例子 [英] Super-simple example of C# observer/observable with delegates

问题描述

我最近开始挖掘到C＃中，但是我不知道如何在语言中实现观察者/可观察模式时代表如何工作。

可能有人给我一个超简单的例子，说明它是如何完成的？我发现这个例子是，但我发现的所有例子也是特别有问题的，也是太笨拙的。

解决方案

观察者模式通常通过事件实现。

这里有一个例子：

  using System; 
 
 class Observable 
 {
 public event EventHandler SomethingHappened; 
 
 public void DoSomething（）
 {
 EventHandler handler = SomethingHappened; 
 if（handler！= null）
 {
 handler（this，EventArgs.Empty）; 
} 
} 
} 
 
 class Observer 
 {
 public void HandleEvent（object sender，EventArgs args）
 {
 Console.WriteLine（发生了什么事+发件人）; 
} 
} 
 
 class Test 
 {
 static void Main（）
 {
可观察的observable = new Observable ; 
 Observer observer = new Observer（）; 
 observable.SomethingHappened + = observer.HandleEvent; 
 
 observable.DoSomething（）; 
} 
} 
  

有关更多详细信息，请参阅链接的文章。 / p>

I recently started digging into C# but I can't by my life figure out how delegates work when implementing the observer/observable pattern in the language.

Could someone give me a super-simple example of how it is done? I have googled this, but all of the examples I found were either too problem-specific or too "bloated".

解决方案

The observer pattern is usually implemented with events.

Here's an example:

using System;

class Observable
{
    public event EventHandler SomethingHappened;

    public void DoSomething()
    {
        EventHandler handler = SomethingHappened;
        if (handler != null)
        {
            handler(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();
    }
}

See the linked article for a lot more detail.

这篇关于C＃观察者/观察者与代表的超简单例子的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持IT屋！