I tried: import System import System.Windows @clr.clrmethod([System.object, System.Windows.RoutedEventArgs]) def OnStartButton(sender,args): #do stuff pass and get: ‘Cannot perform runtime binding on a null referenceAttributeError : object’ So I tried subscribing to the Click event from the Python end and that works. However, that’s not so good for me so I tried subclassing Button in C# and debugging what is passed to the Click event when subscribing from Python and sure enough, it is a RoutedEventhandler (even without the @clr.crlmethod decorator). There must be a way to pass-in the method to C#!! Background: this is an application to support simple GUI development in Python. The C# end handles creating and displaying the GUI components which results in very simple Python: # works in IronPython b = app.Button("Start", OnStartButton) # can’t use OnStartButton as argument, have to add this in Python.NET :-( b.Click += OnStartButton By the way I’m using Python.Net with PyScope from my own build. Steve From: PythonDotNet [mailto:pythondotnet-bounces+steve.ward=oxinst.com@python.org] On Behalf Of Denis Akhiyarov Sent: 20 June 2018 05:18 To: A list for users and developers of Python for .NET Subject: -|EXT|- Re: [Python.NET] Cast PyObject to RoutedEventHandler Have you tried @clrmethod decorator? https://github.com/pythonnet/pythonnet/blob/master/src/runtime/resources/clr... https://github.com/pythonnet/pythonnet/blob/master/src/tests/test_clrmethod.... On Tue, Jun 19, 2018 at 10:37 AM, WARD Steve <Steve.Ward@oxinst.com<mailto:Steve.Ward@oxinst.com>> wrote: Can anyone tell me how to cast or Convert (or use a TryGet, or As whatever…), a PyObject (a Python function), to a C# RoutedEventHandler? The Python function: def OnStartButton(sender,args): #do stuff pass Thanks Steve ___________________________________________________________________________ This e-mail is confidential and is for the addressee only. Please refer to www.oxinst.com/email-statement<http://www.oxinst.com/email-statement> for regulatory information. _________________________________________________ Python.NET mailing list - PythonDotNet@python.org<mailto:PythonDotNet@python.org> https://mail.python.org/mailman/listinfo/pythondotnet ___________________________________________________________________________ This e-mail is confidential and is for the addressee only. Please refer to www.oxinst.com/email-statement<http://www.oxinst.com/email-statement> for regulatory information.