[python-win32] Passing Nothing into ReferencesEvents - resolved, however can't bind events
shivisi
shivisi at nana10.co.il
Sat Oct 17 21:30:03 CEST 2009
Thanks for taking the time to answer, and for pywin. I've been using pywin with COM for some time, and am only now (when something doesn't "just work") starting to appreciate its internal complexities.
I get back the following error:
>>> com_error: (-2147467262, 'No such interface supported', None, None)
I have a very sketchy understanding of COM's internals, but if the IDispatch interface was supported, wouldn't Dispatch() be using that?
Also, is there any way of getting the interfaces which an object does support?
Thanks again,
Zev
-----Original Message-----
From: Mark Hammond [mailto:mhammond at skippinet.com.au]
Sent: Sat 10/17/2009 00:38
To: shivisi
Cc: python-win at python.org
Subject: Re: [python-win32] Passing Nothing into ReferencesEvents - resolved, however can't bind events
Sorry, I did mislead you. After reading this in more detail your
initial code looked correct.
Try something like:
disp =
acc.VBE.Events.ReferencesEvents(None).QueryInterface(pythoncom.IID_IDispatch)
refsEvents=DispatchWithEvents(disp,RefEvents)
To ensure we are passing an IDispatch rather than an IUnknown to
DispatchWithEvents.
HTH,
Mark
On 16/10/2009 7:32 PM, shivisi wrote:
> I'm confused.
>
> DispatchWithEvents fails on Access.Application, because there are no events on that object.
> The events of interest are on the associated VB Editor/VB Project, via the VBA Extensibility Library. VBE is the root object of that library, and that is the type of acc.VBE.
> These events are retrieved with the whole path:
>>>> acc.VBE.Events.ReferencesEvents(None)
> where acc is the Access.Application object.
>
> If the Access.Application did have events, would win32com.PumpMessages() return events for all the child objects?
> If it does, then perhaps I can use:
>>>> DispatchWithEvents(acc.VBE.Events,RefEvents)
>>>> win32com.PumpMessages()
> However, ReferencesEvents is a "property with arguments", and needs to be passed None.
>
> It seems that ReferencesEvents(None) returns a PyIUnknown object, and DispatchWithEvents can only bind to (at a minimum) PyIDispatch. Would comtypes help me here?
>
> -----Original Message-----
> From: Mark Hammond [mailto:skippy.hammond at gmail.com]
> Sent: Fri 10/16/2009 02:00
> To: shivisi
> Cc: python-win32 at python.org
> Subject: Re: [python-win32] Passing Nothing into ReferencesEvents - resolved, however can't bind events
>
> On 15/10/2009 10:50 PM, shivisi wrote:
>> Passing Application.VBE.Events.ReferencesEvents(None) works (at least at this point).
>> However, when I try to bind to an event class, I get the error below.
>> Any assistance, debugging suggestions, would be greatly appreciated.
>> Thanks.
>>
>> # 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)
>
>
> See the docstring for DispatchWithEvents - you probably want something
> closer to:
>
> acc = DispatchWithEvents('Access.Application', RefEvents)
> acc.Visible = True
> win32com.PumpMessages() # sit here doing nothing but waiting for events...
>
> Cheers,
>
> Mark
>
>
>> #-----------------------------------------------------------------------------
>> Traceback (most recent call last):
>> File "<interactive input>", line 1, in<module>
>> File "C:\Python26\lib\site-packages\win32com\client\__init__.py", line 245, in DispatchWithEvents
>> disp = Dispatch(clsid)
>> File "C:\Python26\lib\site-packages\win32com\client\__init__.py", line 96, in Dispatch
>> return __WrapDispatch(dispatch, userName, resultCLSID, typeinfo, clsctx=clsctx)
>> File "C:\Python26\lib\site-packages\win32com\client\__init__.py", line 43, in __WrapDispatch
>> return dynamic.Dispatch(dispatch, userName, WrapperClass, typeinfo, clsctx=clsctx)
>> File "C:\Python26\lib\site-packages\win32com\client\dynamic.py", line 118, in Dispatch
>> typeinfo = IDispatch.GetTypeInfo()
>> AttributeError: 'PyIUnknown' object has no attribute 'GetTypeInfo'
>> #-----------------------------------------------------------------------------
>>>>> acc.VBE.Events.ReferencesEvents
>> <bound method Events.ReferencesEvents of<win32com.gen_py.Microsoft Visual Basic for Applications Extensibility 5.3.Events instance at 0x17466752>>
>>>>> acc.VBE.Events.ReferencesEvents(None)
>> <PyIUnknown at 0x0102CFF8 with obj at 0x00190AEC>
>>
>>
>> Original message:
>>> I am writing a COM addin, and attempting to trap the ItemAdded/ItemRemoved event in the following object:
>>> Application.VBE.Events.ReferencesEvents
>>> which is retrieved by passing Nothing as a paramter:
>>> Application.VBE.Events.ReferencesEvents(Nothing)
>>>
>>> Tim Golden wrote in the following post (http://mail.python.org/pipermail/python-win32/2009-February/008826.html) that pythoncom.Empty can be used for Nothing. However, when trying this:
>>>
>>> try:
>>> self.comRefevents=self.app.VBE.Events.ReferencesEvents(pythoncom.Empty)
>>> except pythoncom.com_error, (hr, msg, exc, arg):
>>> print "The call failed with code %d: %s" % (hr, msg)
>>> if exc is None:
>>> print "There is no extended error information"
>>> else:
>>> wcode, source, text, helpFile, helpId, scode = exc
>>> print "The source of the error is", source
>>> print "The error message is", text
>>> print "More info can be found in %s (id=%d)" % (helpFile, helpId)
>>>
>>> I get back the following (the same as if I had passed no arguments at all):
>>>
>>> The call failed with code -2147352561: Parameter not optional.
>>> There is no extended error information
>>>
>>> Eric Lippert states in his blog (http://blogs.msdn.com/ericlippert/archive/2004/07/14/183241.aspx):
>>>> A common alternative to passing a missing argument is to pass Nothing, Null, or Empty in VBScript,
>>>> null or undefined in JScript. Null and null pass VT_NULL, Empty and undefined pass VT_EMPTY, and
>>>> Nothing passes a VT_DISPATCH with no value dispatch object pointer.
>>> It would seem that VB's Nothing and Empty are two different things.
>>>
>>> If I try passing pythoncom.VT_DISPATCH, then I get the following traceback:
>>>
>>> -----------------------------------------------------------------------------------------------------------
>>> Traceback (most recent call last):
>>> File "C:\Python26\lib\site-packages\win32com\universal.py", line 177, in dispatch
>>> retVal = ob._InvokeEx_(meth.dispid, 0, meth.invkind, args, None, None)
>>> File "C:\Python26\lib\site-packages\win32com\server\policy.py", line 324, in _InvokeEx_
>>> return self._invokeex_(dispid, lcid, wFlags, args, kwargs, serviceProvider)
>>> File "C:\Python26\lib\site-packages\win32com\server\policy.py", line 649, in _invokeex_
>>> return DesignatedWrapPolicy._invokeex_( self, dispid, lcid, wFlags, args, kwArgs, serviceProvider)
>>> File "C:\Python26\lib\site-packages\win32com\server\policy.py", line 585, in _invokeex_
>>> return func(*args)
>>> File "C:\Documents and Settings\ABG7\My Documents\Zevi\Python-COMAddin\VBACodeRepository.py", line 104, in OnConnection
>>> self.comRefevents=self.app.VBE.Events.ReferencesEvents(pythoncom.VT_DISPATCH)
>>> File "C:\Python26\lib\site-packages\win32com\gen_py\0002E157-0000-0000-C000-000000000046x0x5x3.py", line 145, in ReferencesEvents
>>> ret = self._oleobj_.InvokeTypes(202, LCID, 2, (13, 0), ((13, 1),),VBProject
>>> TypeError: The Python instance can not be converted to a COM object
>>> pythoncom error: Unexpected gateway error
>>>
>>> Traceback (most recent call last):
>>> File "C:\Python26\lib\site-packages\win32com\universal.py", line 177, in dispatch
>>> retVal = ob._InvokeEx_(meth.dispid, 0, meth.invkind, args, None, None)
>>> File "C:\Python26\lib\site-packages\win32com\server\policy.py", line 324, in _InvokeEx_
>>> return self._invokeex_(dispid, lcid, wFlags, args, kwargs, serviceProvider)
>>> File "C:\Python26\lib\site-packages\win32com\server\policy.py", line 649, in _invokeex_
>>> return DesignatedWrapPolicy._invokeex_( self, dispid, lcid, wFlags, args, kwArgs, serviceProvider)
>>> File "C:\Python26\lib\site-packages\win32com\server\policy.py", line 585, in _invokeex_
>>> return func(*args)
>>> File "C:\Documents and Settings\ABG7\My Documents\Python-COMAddin\VBACodeRepository.py", line 104, in OnConnection
>>> self.comRefevents=self.app.VBE.Events.ReferencesEvents(pythoncom.VT_DISPATCH)
>>> File "C:\Python26\lib\site-packages\win32com\gen_py\0002E157-0000-0000-C000-000000000046x0x5x3.py", line 145, in ReferencesEvents
>>> ret = self._oleobj_.InvokeTypes(202, LCID, 2, (13, 0), ((13, 1),),VBProject
>>> TypeError: The Python instance can not be converted to a COM object
>>>
>>>
>>> _______________________________________________
>>> python-win32 mailing list
>>> python-win32 at python.org
>>> http://mail.python.org/mailman/listinfo/python-win32
>
>
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