问题描述
我在 SO 上看到了一些关于这个习语的提及(包括在 SO):
I have seen a few mentions of this idiom (including on SO):
// Deliberately empty subscriber
public event EventHandler AskQuestion = delegate {};
好处很明显 - 它避免了在引发事件之前检查 null 的需要.
The upside is clear - it avoids the need to check for null before raising the event.
但是，我很想知道是否有任何缺点.例如，它是否被广泛使用并且足够透明，不会引起维护问题?空事件订阅者调用是否有任何明显的性能影响?
However, I am keen to understand if there are any downsides. For example, is it something that is in widespread use and is transparent enough that it won't cause a maintenance headache? Is there any appreciable performance hit of the empty event subscriber call?
推荐答案
唯一的缺点是非常轻微的性能损失，因为您调用了额外的空委托.除此之外，没有维护罚款或其他缺点.
The only downside is a very slight performance penalty as you are calling extra empty delegate. Other than that there is no maintenance penalty or other drawback.
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