Mailman 3 October 2003 - Python.NET

Subclassing again
by Michael.Amrhein＠t-online.de Oct. 31, 2003

Oct. 31, 2003

Hi, there seem to be some more issues with subclassing. I just stumble over the following: Python 2.3.2 (#49, Oct 2 2003, 20:02:00) [MSC v.1200 32 bit (Intel)] on win32 Type "help", "copyright", "credits" or "license" for more information. >>> import CLR >>> from CLR.System.Drawing import Point >>> class P(Point): ... def __repr__(self): ... return 'P(%s,%s)' % self.X, self.Y ... >>> p=P() >>> p <CLR.P object at 0x008EDA30> >>> repr(p) '<CLR.P object at 0x008EDA30>' P.__repr__ not called ?!? >>> p.X Traceback (most recent call last): File "<stdin>", line 1, in ? TypeError: Das Objekt stimmt mit dem Zieltyp nicht überein. (saying: The object does not match the target type.) Point methods can't be invoked on P instance ?!? Any ideas? Michael

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Subclassing CLR types
by Michael.Amrhein＠t-online.de Oct. 31, 2003

Oct. 31, 2003

Hi, subclassing CLR types does work as long as you hold a reference to the instance of the subclass in Python. But when you pass a subclassed object to a CLR object and retrieve this object later through a method of the CLR object you don't get an instance of the subclass but an instance of the CLR base class the subclass was derived from: Python 2.3.2 (#49, Oct 2 2003, 20:02:00) [MSC v.1200 32 bit (Intel)] on win32 Type "help", "copyright", "credits" or "license" for more information. >>> import CLR >>> from CLR.System.Windows.Forms import Control >>> c=Control("This is a Control.") >>> class myControl(Control): ... def dummy(self): ... return self.Text ... >>> m=myControl(c, "This is a myControl.") >>> m.Parent <CLR.System.Windows.Forms.Control object at 0x008F6F70> >>> m.Parent.Text u'This is a Control.' >>> c.Contains(m) True >>> m.dummy() u'This is a myControl.' >>> c.Controls[0] == m True [Every thing ok, so far, but ...] >>> c.Controls[0].dummy() Traceback (most recent call last): File "<stdin>", line 1, in ? AttributeError: 'Control' object has no attribute 'dummy' [Because ...] >>> type(c.Controls[0]) <class 'CLR.System.Windows.Forms.Control'> This is weird because it means that when I get back an instance of a subclass from some CLR method I don't know the correct type and can not act on it properly. I don't know if there's an easy way to come around this problem but to me subclassing of CLR types seemes pretty useless without a solution for it. If there is some kind of unique reference from the Python wrapper instances to the CLR instances a starting point for a solution may be to base all wrappers on a base type which keeps a mapping of referenced CLR instances to wrapper instances. Something like this (all not tested yet!!!): class CLRObj(object): from weakref import WeakValueDictionary __objMap = WeakValueDictionary() def __new__(cls, ref): try: obj = clrObj.__objMap[ref] except KeyError: obj = object.__new__(cls) obj._ref = ref clrObj.__objMap[ref] = obj return obj def __del__(self): self._ref.Dispose() class <wrapper>(CLRObj): def __new__(cls, ...): ref = <create base CLR type> return CLRObj.__new__(cls, ref) ... and when receiving a CLR instance turn it into the corresponding wrapper instance by obj = CLRObj(clrObj) This will not work if you receive some kind of CLR object which was created internally by some CLR method and not through a wrapper. But you will get all object you created through the wrappers back as instances of the correct type. If I'm galloping in the wrong direction please give me a short stop signal. If not ... lets figure out the probably missing details. Michael

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RE: [Python.NET] Do assemblies need to be placed into the GAC
by Felix McAllister Oct. 30, 2003

Oct. 30, 2003

Brian, Thanks for that. We don't currently put our assemblies into the GAC because our ASP.NET app can (theoretically) support multiple versions on the one server machine. Each version lives in a separate sub-directory that then contains a 'bin' directory for the assembly DLLs. Although you *can* put multiple versions of the same component into the GAC (as long as the AssemblyVersion number is different), how would Python.NET distinguish these? Felix. >From: "Brian Lloyd" <brian(a)zope.com> >To: "Felix McAllister" <felix_mcallister(a)hotmail.com>, ><pythondotnet(a)python.org> >Subject: RE: [Python.NET] Do assemblies need to be placed into the GAC >Date: Wed, 29 Oct 2003 09:30:34 -0500 > > > I'd like to use PythonNet to script some .NET assemblies we have. Must I > > place these into the GAC? I've tried to put the python script > > into the same > > directory as the assembly DLL but this doesn't work: > >Hi Felix - > >Right now to import an assembly it either needs to be in the GAC >or in the "application directory" or a subdirectory thereof. > >When running python, the application directory is the directory >where python.exe lives, not the place where the script you are >running lives. > >One of the things I want to do for the final is see if there is >a way to have the assembly loader use the python path (sys.path) >when looking for assemblies. > > >Brian Lloyd brian(a)zope.com >V.P. Engineering 540.361.1716 >Zope Corporation http://www.zope.com > > _________________________________________________________________ MSN 8 helps eliminate e-mail viruses. Get 2 months FREE*. http://join.msn.com/?page=features/virus

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System.NullReferenceException
by Michael.Amrhein＠t-online.de Oct. 30, 2003

Oct. 30, 2003

Hi, when unregistering an event handler I get an exection: Python 2.3.2 (#49, Oct 2 2003, 20:02:00) [MSC v.1200 32 bit (Intel)] on win32 Type "help", "copyright", "credits" or "license" for more information. >>> import CLR >>> import CLR.System.Windows.Forms as wf >>> f=wf.Form() >>> f <CLR.System.Windows.Forms.Form object at 0x008FE6D0> >>> def h(s,a): print s,a ... >>> f.Click += h >>> f.Click -= h Unbehandelte Ausnahme: System.NullReferenceException: Der Objektverweis wurde nicht auf eine Objektinstanz festgelegt. at Python.Runtime.EventObject.RemoveEventHandler(IntPtr target, IntPtr handler) at Python.Runtime.EventBinding.nb_inplace_subtract(IntPtr ob, IntPtr arg) The same happens when I try to call the event. The demo apps run without any problem; i.e. Python event handlers are called correctly by the CLR. But trying to unregister the event handler in helloform.py: ... WinForms.MessageBox.Show("Please do not press this button again.") self.button.Click -= self.button_Click causes the same exception as shown above. Michael P.S.: I run CLR v1.1 on Win XP

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Dragging the window
by david Powell Oct. 29, 2003

Oct. 29, 2003

When I drag the window of the demo applications I get a trail of Windows. That is to say the area exposed by moving the window is not being repainted. I have seen the same problem with wxPython. Any comments? David

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Do assemblies need to be placed into the GAC
by Felix McAllister Oct. 29, 2003

Oct. 29, 2003

Hi, I'd like to use PythonNet to script some .NET assemblies we have. Must I place these into the GAC? I've tried to put the python script into the same directory as the assembly DLL but this doesn't work: C:\dev\python\PythonNetTest\bin\Debug>python Python 2.3.2 (#49, Oct 2 2003, 20:02:00) [MSC v.1200 32 bit (Intel)] on win32 Type "help", "copyright", "credits" or "license" for more information. >>>import CLR >>>import CLR.PythonNetTest Traceback (most recent call last): File "<stdin>", line 1, in ? ImportError: No module named PythonNetTest >>>import CLR.PythonNetTest.MyTest Traceback (most recent call last): File "<stdin>", line 1, in ? ImportError: No module named PythonNetTest >>> TIA, Felix. _________________________________________________________________ Help STOP SPAM with the new MSN 8 and get 2 months FREE* http://join.msn.com/?page=features/junkmail

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Problem installing
by Amos Latteier Oct. 28, 2003

Oct. 28, 2003

david Powell wrote: >I downloaded the files. I can run the demo in your version of python but >not in my existing version of python 2.3. That's to be expected. Your existing python 2.3 doesn't connect to dot net. That's what Brian's Python does. -Amos

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Problem installing
by david Powell Oct. 28, 2003

Oct. 28, 2003

First, thanks for a very exciting development. I downloaded the files. I can run the demo in your version of python but not in my existing version of python 2.3. I followed the instructions:- "Yes, at least on win32 systems. Just copy the files Python.Runtime.dll and CLR.dll from the PythonNet directory to the root directory of your python installation." I get the error D:\Python23>python d:\pythonnet\pythonnet-1.0-beta1\demo\helloform.py Traceback (most recent call last): File "d:\pythonnet\pythonnet-1.0-beta1\demo\helloform.py", line 12, in ? import CLR.System.Windows.Forms as WinForms ImportError: No module named System.Windows.Forms Any help very much appreciated. David

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[Python.NET List] Test message
by Brian Lloyd Oct. 28, 2003

Oct. 28, 2003

its aliiiiivvvvve.... Brian Lloyd brian(a)zope.com V.P. Engineering 540.361.1716 Zope Corporation http://www.zope.com

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