James Teh schrieb: > Hi all, > > I've had cause to instantiate a COM class which is not registered on the > system. To do this, one uses DllGetClassObject on the dll and then calls > CreateInstance on the resulting IClassFactory. > > IClassFactory::CreateInstance is defined as: > HRESULT CreateInstance( > [in] IUnknown *pUnkOuter, > [in] REFIID riid, > [out] void **ppvObject > ); > > However, in comtypes.server.IClassFactory, CreateInstance is defined as > follows: > _methods_ = [ > comtypes.STDMETHOD(comtypes.HRESULT, "CreateInstance", > [ctypes.c_int, > ctypes.POINTER(comtypes.GUID), ctypes.POINTER(ctypes.c_ulong)]), > ... > > The final parameter being declared as c_ulong makes life a little > painful. In order to use it, you have to do something like: > instance = ctypes.c_ulong() > factory.CreateInstance(0, interface._iid_, ctypes.byref(instance)) > instance = ctypes.POINTER(interface)(instance.value) > > First of all, is there a reason that last parameter is c_ulong instead > of c_void_p or the like?
I do not remember the details, but it looks strange. And the first parameter type is also wrong, it should be a pointer. > Second, is there any chance we could make this more Pythonic like the > recent IServiceProvider.QueryInterface? Something like: > instance = factory.CreateInstance(interface=interface) > I'm curious as to how frequently this is already used, as such a change > would break existing usage. I don't think anyone was using the IClassFactory::CreateInstance method, otherwise I think I've heard this complaint earlier. So, I have now in svn implemented the following: - Fixed the IClassFactory::CreateInstance method - Implemented a Pythonic interface for it, also including the nice 'dynamic=False' parameter. - Implemented a low-level comtypes.CoGetClassObject() function, and a high level comtypes.client.GetClassObject() Please have a look at it and report your observations. -- Thanks, Thomas ------------------------------------------------------------------------------ Let Crystal Reports handle the reporting - Free Crystal Reports 2008 30-Day trial. Simplify your report design, integration and deployment - and focus on what you do best, core application coding. Discover what's new with Crystal Reports now. http://p.sf.net/sfu/bobj-july _______________________________________________ comtypes-users mailing list comtypes-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/comtypes-users
