Notify listeners that event is occurring
H— Event source
Event source, specified as a handle array. All of the objects
H must define the named event.
EventName— Name of event
Name of event, specified as case-sensitive, quoted text that
is defined by the class of
data— User-defined event data
Listener callbacks should not reuse the same event data object
in subsequent calls to
notify. Always create
a new event data object to pass to
To learn about attributes of methods, see Method Attributes.