.Net观察者模式的变化。什么时候发生这些，为什么？

I was just trying to explain the Observer pattern to a colleague for use in a C# application. I remarked that is should be easy enough to implement by looking up some MSDN documentation. However, I was surprised to find that the MSDN example deviates from how I've been taught the Observer pattern. Mind you, I've primarily used the pattern in Java, but I was under the impression that the .Net implementation was pretty much the same. I was just trying to explain the Observer patte