C# – Unit test an event handler

An event handler is a method that is registered to listen to an event. When the event is invoked, the event handler method is called. You may be tempted to directly call the event handler to unit test it. It’s better to actually raise the event though, and then check the side effects of the … Read more

C# – How to use FileSystemWatcher

You can use the FileSystemWatcher class to detect file system changes, such as when a file is created, deleted, modified, or renamed. When a change happens, it raises an event that you can handle. This is an event-based alternative to polling for file changes. In this article, I’ll show how to use FileSystemWatcher to detect … Read more

C# – Example of using events

Events are an implementation of the observer pattern and consists of two parts: There are three simple steps to using events, which I’ll show below. 1 – Add an event field The first step is to add an event field to a class with the event keyword and a delegate type (such as the generic … Read more