[Python.NET] System.NullReferenceException

Brian Lloyd brian at zope.com
Wed Oct 29 21:12:24 EST 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

Ah - what a wonderful, horrible experience its been, learning all 
about these little nits of the CLR :)

This seems to be related to events that are implemented using 
internalcall magic. The correct 'official' reflection api one is 
supposed to use to ignore these details is totally broken in both 
CLR 1.0 & 1.1, and it seems that my workaround needs some more 
work ;^/

I've added a (currently failing) unit test to make sure it gets 
looked at.

Thanks!



Brian Lloyd        brian at zope.com
V.P. Engineering   540.361.1716              
Zope Corporation   http://www.zope.com 





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