在C＃中用Lambdas解决事件 [英] UnHooking Events with Lambdas in C#

问题描述

我经常碰到一个我想订阅一个事件的情况，但是我想使用一个lambda来实现：

I often run into a situation where I want to subscribe to an event, but I want to use a lambda to do so:

public class Observable
{
    public event EventHandler SomethingHappened;

    public void DoSomething()
    {
        // Do Something...
        OnSomethingHappened();
    }
}

// Somewhere else, I hook the event
observable.SomethingHappened += (sender, args) => Console.WriteLine("Something Happened");

我遇到的问题是我不知道如何解除事件。由于lambda在引擎盖下创建了一个匿名委托，所以我没有什么可以调用 - = 。

The problem I run into is that I don't know how to unhook the event. Since the lambda creates an anonymous delegate under the hood, I have nothing to call -= on.

我可以创建一个方法：

private void SomethingHappened(object sender, EventArgs args)
{
    Console.WriteLine("Something Happened");
}

然后我可以挂钩/取消挂钩我想要的：

And then I can hook/unhook all I want:

observable.SomethingHappened += SomethingHappened;
observable.SomethingHappened -= SomethingHappened;

但我真的很想使用我的lambda。在一个更复杂的例子中，羊羔在这里非常方便。

But I'd really, really, really like to use my lambda instead. In a more complicated example, lambdas come in really handy here.

我很确定我没有运气，但我想知道有没有人想出了这样做？

I am pretty sure that I am out of luck... but I was wondering if anyone out there has figured out a way to do this?

推荐答案

不用说，没有一个很好的方式来做到这一点。

Unforutantely there is not a great way to do this. You are really stuck with one of two options

• 使用您所描述的方法


• 分配lambda到变量，并使用该变量来添加/删除事件

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