[python-win32] issues with win32com constants and static/dynamicdispatch

[Jason Ferrara]

c = win32com.client.Dispatch(c.QueryInterface(pythoncom.IID_IDispatch))

works. Thanks!

FYI, c=win32com.client.Dispatch(c) does not.

 >>> c=win32com.client.Dispatch(c)
Traceback (most recent call last):
   File "<stdin>", line 1, in <module>
   File "C:\Python25\Lib\site-packages\win32com\client\__init__.py",  
line 96, in Dispatch
     return __WrapDispatch(dispatch, userName, resultCLSID, typeinfo,  
UnicodeToString, clsctx)
   File "C:\Python25\Lib\site-packages\win32com\client\__init__.py",  
line 44, in __WrapDispatch
     return dynamic.Dispatch(dispatch, userName, WrapperClass,  
typeinfo, UnicodeToString=UnicodeToString,clsctx=clsctx)
   File "C:\Python25\lib\site-packages\win32com\client\dynamic.py",  
line 111, in Dispatch
     typeinfo = IDispatch.GetTypeInfo()
AttributeError: 'PyIUnknown' object has no attribute 'GetTypeInfo'




On Jul 4, 2007, at 7:03 PM, Mark Hammond wrote:

> That is strange - the problem is that the resulting COM object is  
> returning an IUnknown rather than an IDispatch.  A work around  
> should be to say:
>
> c = cams[0]
> c = win32com.client.Dispatch(c)
>
> or possibly:
>
> c = win32com.client.Dispatch(c.QueryInterface 
> (pythoncom.IID_IDispatch))
>
> I think we could also argue this is a bug in win32com - it should  
> try and QI any IUnknown objects - but changing this might break  
> existing code...
>
> Mark
> -----Original Message-----
> From: python-win32-bounces at python.org [mailto:python-win32- 
> bounces at python.org]On Behalf Of Jason Ferrara
> Sent: Thursday, 5 July 2007 12:30 AM
> To: python-win32 at python.org
> Subject: [python-win32] issues with win32com constants and static/ 
> dynamicdispatch
>
> I'm trying to use a COM library from python.
>
> If I use dynamic dispatch, the com objects all behave correctly,  
> but the constants defined in the COM library don't show up.
>
> If I use static dispatch, the constants show up, but COM objects  
> returned by calls into the COM library seem broken.
>
> As example, starting with dynamic dispatch
>
>   Python 2.5.1 (r251:54863, Apr 18 2007, 08:51:08) [MSC v.1310 32  
> bit (Intel)] on win32
>   Type "help", "copyright", "credits" or "license" for more  
> information.
>   >>> import win32com.client
>   >>> mi=win32com.client.Dispatch("MIDLIBCom.MIDLib")
>   >>> cams=mi.OpenCameras("C:\Program Files\Micron Imaging 
> \sensor_data")
>   >>> c=cams[0]
>   >>> print c
>   <COMObject OpenCameras>
>   >>> print c.productName
>   Micron Imaging DEMO2
>
> So far everything is fine, but now...
>
>   >>> print win32com.client.constants.MI_BAYER_8
>   Traceback (most recent call last):
>     File "<stdin>", line 1, in <module>
>     File "C:\Python25\Lib\site-packages\win32com\client 
> \__init__.py", line 168, in
>    __getattr__
>       raise AttributeError, a
>   AttributeError: MI_BAYER_8
>
> This is no good. So now I try static dispatch
>
>   Python 2.5.1 (r251:54863, Apr 18 2007, 08:51:08) [MSC v.1310 32  
> bit (Intel)] on win32
>   Type "help", "copyright", "credits" or "license" for more  
> information.
>   >>> import win32com.client
>   >>> mi=win32com.client.gencache.EnsureDispatch("MIDLIBCom.MIDLib")
>   >>> print win32com.client.constants.MI_BAYER_8
>   1
>
> Things are looking better, but now...
>
>   >>> cams=mi.OpenCameras("C:\Program Files\Micron Imaging 
> \sensor_data")
>   >>> c=cams[0]
>   >>> print c
>   <PyIUnknown at 0xac640c with obj at 0xf0d808>
>   >>> print c.productName
>   Traceback (most recent call last):
>     File "<stdin>", line 1, in <module>
>   AttributeError: 'PyIUnknown' object has no attribute 'productName'
>
>
> So whats going on here? What am I doing wrong?
>
> Thanks
>
> - J
>
>
>
>
>

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