[python-win32] Passing Nothing into ReferencesEvents - resolved, however can't bind events [SEC=PERSONAL]

[Thomas Heller]

Zev Spitz schrieb:
> I am coming from VBA, and my understanding of COM internals is very weak.
> 
> 2 questions:
> 1) What do I replace IWhatever with, and how do I find that out? (The 
> argument is supposed to be of type VBProject)
> 2) How do I get an instance of IWhatever?
> 

>From your original post:
> # Code
> from win32com.client import Dispatch, DispatchWithEvents, getevents
> 
> class RefEvents:
>     def OnItemAdded(self,ref):
>         print '--Event - Reference added'
>     def OnItemRemoved(self,ref):
>         print '--Event - Reference removed'
> 
> acc=Dispatch('Access.Application')
> acc.Visible=True
> refsEvents=DispatchWithEvents(acc.VBE.Events.ReferencesEvents(None),RefEvents)

I don't have Access installed, but I assume Word is somewhat similar.
So, here we go:

Python 2.5.4 (r254:67916, Dec 23 2008, 15:10:54) [MSC v.1310 32 bit (Intel)] on win32
Type "help", "copyright", "credits" or "license" for more information.
>>> from comtypes.client import CreateObject, ShowEvents
>>> acc = CreateObject("Word.Application")
# Generating comtypes.gen._00020905_0000_0000_C000_000000000046_0_8_3
# Generating comtypes.gen._00020430_0000_0000_C000_000000000046_0_2_0
# Generating comtypes.gen.stdole
# Generating comtypes.gen._2DF8D04C_5BFA_101B_BDE5_00AA0044DE52_0_2_3
# Generating comtypes.gen.Office
# Generating comtypes.gen._0002E157_0000_0000_C000_000000000046_0_5_3
# Generating comtypes.gen._2DF8D04C_5BFA_101B_BDE5_00AA0044DE52_0_2_4
# Generating comtypes.gen.VBIDE
# Generating comtypes.gen.Word
>>> acc.Visible = True
>>> acc.VBE.Events
Traceback (most recent call last):
  File "<stdin>", line 1, in <module>
_ctypes.COMError: (-2146822220, None, (u'Dem programmatischen Zugriff auf das Visual Basic-Projekt wird nicht vertraut.'
, u'Microsoft Word', u'C:\\Programme\\Microsoft Office\\OFFICE11\\1031\\wdmain11.chm', 25548, None))
>>>

(The error message means somewhat like 'The programmatic access to the visual basic project is not trusted.
I use the 'Extras' menu in Word to change the macro security settings andtry again:)

>>> acc.VBE.Events
<POINTER(Events) ptr=0x2929bc at 1224170>
>>>

(Ah, some progress)

>>> acc.VBE.Events.ReferencesEvents(None)
Traceback (most recent call last):
  File "<stdin>", line 1, in <module>
  File "c:\sf\comtypes\comtypes\__init__.py", line 795, in __call__
    return self.getter(self.im_inst, *args)
ctypes.ArgumentError: argument 1: <type 'exceptions.TypeError'>: None
>>>

Ok, None is not accepted.  Grepping in the comtypes\gen directory for 'ReferencesEvents'
I find this code snippet in file '_0002E157_0000_0000_C000_000000000046_0_5_3.py':

Events._methods_ = [
    COMMETHOD([dispid(202), 'propget'], HRESULT, 'ReferencesEvents',
              ( ['in'], POINTER(VBProject), 'VBProject' ),
              ( ['retval', 'out'], POINTER(POINTER(ReferencesEvents)), 'prceNew' )),
    COMMETHOD([dispid(205), 'propget'], HRESULT, 'CommandBarEvents',
              ( ['in'], POINTER(IDispatch), 'CommandBarControl' ),
              ( ['retval', 'out'], POINTER(POINTER(CommandBarEvents)), 'prceNew' )),
]

So, it seems we need a POINTER(VBProject).  VBProject is a CoClass, implementing the
_VBProject COM interface.

Further grepping shows the comtypes\gen\VBIDE.py is an alias module for
comtypes\gen\_0002E157_0000_0000_C000_000000000046_0_5_3.py, so we use the
former because it is much easier to type:

>>> from comtypes.gen import VBIDE
>>> from ctypes import POINTER

>>> acc.VBE.Events.ReferencesEvents(POINTER(VBIDE._VBProject)())
<POINTER(_ReferencesEvents) ptr=0x274f2c at 11c7490>
>>>

(The idiom 'POINTER(VBIDE._VBProject)()' creates a NULL-pointer to _VBProject)

And finally we try to find some events:

>>> ShowEvents(acc.VBE.Events.ReferencesEvents(POINTER(VBIDE._VBProject)()))
# event found: _dispReferencesEvents_ItemAdded
# event found: _dispReferencesEvents_ItemRemoved
<comtypes.client._events._AdviseConnection object at 0x011BACB0>
>>>

Now, I do not know what I have to do to trigger these events, but
it looks like the code could possibly work.

Thomas