Events of an aggregated object

[alpha137]

Hi COM gurus,

here comes a nice question for you:

I've a simple COM object (named for example InnerObject) which fires events.
Now I'm aggregating this inner object in a second object (say OuterObject).

When I create an OuterObject it works fine to query interface for InnerObject and call the methods of InnerObjects.
But how can I catch the events of InnerObject (create an event sink)?

Thanks for any help.

Alpha137

[Vi2]

By usual way. OuterObject will be the common client of InnerObject.

[alpha137]

Hello Vita,

thanks for your fast reply but I don't understand.

To keep it small and simple I've tested it under VB:

Public WithEvents inner As InnerObject

Private Sub DoIt()
Dim outer As New OuterObject

Set inner = outer
End Sub

This gives me a 'runtime error 459: object or class does not support the set of events'.
Is this just another VB restriction?

Alpha137

[Vi2]

If
Private WithEvents inner As InnerObject
will not help you, then it's not VB limitation. It's your problem with OuterObject and InnerObject objects or their TypeLib.

Your InnerObject coclass must have

[uuid(...),helpstring("InnerObject Class")]
coclass CInnerObject
{
	[default] interface InnerObject;
	[default, source] dispinterface _InnerObjectEvents;
};

Also the OuterObject class must redirect all interface's Query to InnerObject class. Something like

BEGIN_COM_MAP(COuterObject)
...
	COM_INTERFACE_ENTRY_AGGREGATE_BLIND(pInnerObject)

***EDIT***
Or other COM_INTERFACE_ENTRY_***AGGREGATE*** macros family.