pythoncom and IDispatch

[fraca7]

Hello. I got a little problem while using pythoncom to automate IE; for 
some reason, changing the 'selectedIndex' on an instance of 
IHTMLSelectElement doesn't fire the 'onchange' event (I guess this is a 
bug in mshtml).

So, I tried to get the 'onchange' event handler and call it myself. 
According to the docs, this is a simple IDispatch implementation and 
calling Invoke() should do the trick; I actually have a working example 
of this in Delphi.

But I can't manage to get it work in Python; the following code


         idisp = pythoncom.WrapObject(elt.onchange)
         idisp.Invoke(pythoncom.DISPID_VALUE,
                      0x400, # LOCALE_USER_DEFAULT
                      pythoncom.DISPATCH_METHOD,
                      False)

fails with an AttributeError:

Traceback (most recent call last): 

   File "C:\Python22\Lib\site-packages\win32com\server\policy.py", line 
283, in _
Invoke_ 

     return self._invoke_(dispid, lcid, wFlags, args) 

   File "C:\Python22\Lib\site-packages\win32com\server\policy.py", line 
288, in _
invoke_ 

     return S_OK, -1, self._invokeex_(dispid, lcid, wFlags, args, None, 
None)
   File "C:\Python22\Lib\site-packages\win32com\server\policy.py", line 
581, in _
invokeex_ 

     return func(*args) 

   File "ietest.py", line 44, in OnDocumentComplete 

     self.deleg.onDocumentComplete(Dispatch(disp), url) 

   File "ietest.py", line 122, in onDocumentComplete 

     self.current.onDocumentComplete(self, browser, url) 

   File "ietest.py", line 141, in onDocumentComplete 

     sink.nextStep() 

   File "ietest.py", line 96, in nextStep 

     self.current.onStart(self) 

   File "ietest.py", line 191, in onStart 

     False) 

pywintypes.com_error: (-2147352567, 'Exception occurred.', (0, 'Python 
COM Serve
r Internal Error', 'Unexpected Python Error: exceptions.AttributeError: 
_Invoke_
', None, 0, -2147467259), None) 


Did I miss something ?

TIA