为什么我不能将事件标记为NotNull？(Why can't I mark an event as NotNull?)

public class EventBus<T>
{
    [NotNull] // annotation not valid on this declaration type
    private static event Action<T> Events;

    static EventBus()
    {
        // we always have a do-nothing event handler so we don't have to worry about null checks and race conditions
        Events += T => { };
    }
 
 正如评论中所见，我明确地不想在任何地方处理null检查事件。 这是通过在从未调用的构造中分配默认的do-nothing事件来解决的。 Resharper不能自动解决这个问题并不奇怪，所以我想用NotNull注释来注释它。 不幸的是，似乎NotNull不能应用于事件，但Resharper在我调用我的事件时随时警告我“可能的'System.NullReferenceException'”。 
 
 如果resharper会注意到错误，那么应该可以通过注释来避免它。 

public class EventBus<T>
{
    [NotNull] // annotation not valid on this declaration type
    private static event Action<T> Events;

    static EventBus()
    {
        // we always have a do-nothing event handler so we don't have to worry about null checks and race conditions
        Events += T => { };
    }
 
As seen in the comment, I explicitly don't want to have to deal with null checking the Events everywhere. This is solved by assigning a default do-nothing event at construction that is never called. It is not surprising that Resharper can't automatically figure this out so I wanted to annotate it with the NotNull annotation. Unfortunately, it would appear that NotNull cannot be applied to events, yet Resharper doesn't hesitate to warn me about a "Possible 'System.NullReferenceException'" anytime I call my events.
 
If resharper is going to notice the error, it should be possible to get avoid it with annotations.

原文：https://stackoverflow.com/questions/18928136