OnDeleted is called when a file or directory, within the directory being monitored, is deleted.
Some common occurrences, such as copying or moving a file or directory, do not correspond directly to an event, but these occurrences do cause events to be raised. When you copy a file or directory, the system raises a Created event in the directory to which the file was copied, if that directory is being watched. If the directory from which you copied was being watched by another instance of FileSystemWatcher, no event would be raised. For example, you create two instances of FileSystemWatcher. FileSystemWatcher1 is set to watch "C:\My Documents", and FileSystemWatcher2 is set to watch "C:\Your Documents". If you copy a file from "My Documents" into "Your Documents", a Created event will be raised by FileSystemWatcher2, but no event is raised for FileSystemWatcher1. Unlike copying, moving a file or directory raises two events. From the previous example, if you moved a file from "My Documents" to "Your Documents", a Created event would be raised by FileSystemWatcher2 and a Deleted event would be raised by FileSystemWatcher1.
Raising an event invokes the event handler through a delegate. For more information, see Raising an Event.
Notes to Inheritors:
When overriding OnDeleted in a derived class, be sure to call the base class's OnDeleted method.