c# - 从 Protected Virtual Void 方法或直接引发事件有什么不同？

Question

我看了一些教程，我不明白为什么他们会建议从 Virtual Protected 方法而不是直接引发事件，有什么区别？

public delegate void SomethingEventHandler(string s);
public event SomethingEventHandler Something;

public void Main() {

  // Raising an event
  OnSomething(); // Via method
  Something("something"); // Directly
}

protected virtual void OnSomething() 
{
  Something("something");
}

Answer 1

请参阅“开发类库的设计指南”，Event Design :

Do use a protected virtual method to raise each event. This is applicable only to non-static events on unsealed classes, not to structures, sealed classes, or static events.

Complying with this guideline allows derived classes to handle a base class event by overriding the protected method. The name of the protected virtual (Overridable in Visual Basic) method should be the same as the event name prefixed with On. For example, the protected virtual method for an event named "TimeChanged" is named "OnTimeChanged".

⚠ Important

Derived classes that override the protected virtual method are not required to call the base class implementation. The base class must continue to work correctly even if its implementation is not called.