Run-time error 459 when using WithEvents with a class that implements another
- by Ken Keenan
I am developing a VBA project in Word and have encountered a problem with handling events when using a class that implements another.
I define an empty class, IMyInterface:
Public Sub Xyz()
End Sub
Public Event SomeEvent()
And a class, MyClass that implements the above:
Implements IMyInterface
Public Event SomeEvent()
Public Sub Xyz()
' ... code ...
RaiseEvent SomeEvent
End Sub
Private Sub IMyInterface_Xyz()
Xyz
End Sub
If I create a third class, OtherClass, that declares a member variable with the type of the interface class:
Private WithEvents mMy As IMyInterface
and try to initialize this variable with an instance of the implementing class:
Set mMy = New MyClass
I get a run-time error '459': This component doesn't support this set of events.
The MSDN page for this error message states:
"You tried to use a WithEvents
variable with a component that can't
work as an event source for the
specified set of events. For example,
you may be sinking events of an
object, then create another object
that Implements the first object.
Although you might think you could
sink the events from the implemented
object, that isn't automatically the
case. Implements only implements an
interface for methods and properties."
The above pretty much sums up what I'm trying to do. The wording, "that isn't automatically the case", rather than "this is flat-out impossible", seems to suggest that there is some bit of manual work I need to do to get it to work, but it doesn't tell me what! Does anybody know if this is possible in VBA?
