Event names should describe the action that raises the event. To name related events that are raised in a specific sequence, use the present or past tense to indicate the relative position in the sequence of actions. For example, when naming a pair of events raised when closing a resource, you might name them 'Closing' and 'Closed', instead of 'BeforeClose' and 'AfterClose'.
Naming conventions provide a common look for libraries that target the common language runtime. This reduces the learning curve required for new software libraries, and increases customer confidence that the library was developed by someone with expertise in developing managed code.