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
IHTMLSelectElem ent 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.WrapO bject(elt.oncha nge)
idisp.Invoke(py thoncom.DISPID_ VALUE,
0x400, # LOCALE_USER_DEF AULT
pythoncom.DISPA TCH_METHOD,
False)

fails with an AttributeError:

Traceback (most recent call last):

File "C:\Python22\Li b\site-packages\win32c om\server\polic y.py", line
283, in _
Invoke_

return self._invoke_(d ispid, lcid, wFlags, args)

File "C:\Python22\Li b\site-packages\win32c om\server\polic y.py", line
288, in _
invoke_

return S_OK, -1, self._invokeex_ (dispid, lcid, wFlags, args, None,
None)
File "C:\Python22\Li b\site-packages\win32c om\server\polic y.py", line
581, in _
invokeex_

return func(*args)

File "ietest.py" , line 44, in OnDocumentCompl ete

self.deleg.onDo cumentComplete( Dispatch(disp), url)

File "ietest.py" , line 122, in onDocumentCompl ete

self.current.on DocumentComplet e(self, browser, url)

File "ietest.py" , line 141, in onDocumentCompl ete

sink.nextStep()

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

self.current.on Start(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.Attr ibuteError:
_Invoke_
', None, 0, -2147467259), None)


Did I miss something ?

TIA

[Roger Upole]

Re: pythoncom and IDispatch


"fraca7" <fraca7@free.fr > wrote in message news:44688c2a$0 $7047$636a55ce@ news.free.fr...[color=blue]
> Hello. I got a little problem while using pythoncom to automate IE; for some reason, changing the 'selectedIndex' on an
> instance of IHTMLSelectElem ent doesn't fire the 'onchange' event (I guess this is a bug in mshtml).[/color]

As I understand it, this was done as a security measure to foil script
exploits.
[color=blue]
> 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.WrapO bject(elt.oncha nge)
> idisp.Invoke(py thoncom.DISPID_ VALUE,
> 0x400, # LOCALE_USER_DEF AULT
> pythoncom.DISPA TCH_METHOD,
> False)
>
> fails with an AttributeError:
>[/color]

You can access the underlying IDispatch using the
_oleobj_ property, ie elt.onchange._o leobj_.Invoke(. .....)

Alternately, you can also use FireEvent, which would look
something like this (untested):
elt.FireEvent(' onchange',elt.o nchange)


Roger



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