<div dir="ltr">Hi Henning,<div><br></div><div>This feature was implemented by @tonyroberts in 2013 and is tested in CI with test_subclass.py file.</div><div><br></div><div>According to these tests, the missing piece in your code is defining explicitly __namespace__ on the .NET class derived in Python:</div><div><br></div><div><div>In [11]: class StringDoor1(Door):</div><div> ....: __namespace__ = "PythonBaseClass"</div><div> ....: def __init__(self):</div><div> ....: self.status = "closed"</div><div> ....:</div><div> ....: def IsOpen(self):</div><div> ....: print "StringDoor.IsOpen()"</div><div> ....: return self.status == "open"</div><div> ....:</div><div> ....: def Toggle(self):</div><div> ....: print "StringDoor.Toggle()"</div><div> ....: if self.status == "open":</div><div> ....: self.status = "closed"</div><div> ....: else:</div><div> ....: self.status = "open"</div><div><br></div><div>In [12]: d = StringDoor1()</div><div><br></div><div>In [13]: d.status</div><div>Out[13]: 'closed'</div><div><br></div><div>In [14]: d.Open()</div><div>StringDoor.IsOpen()</div><div>StringDoor.Toggle()</div><div><br></div><div>In [15]: d.status</div><div>Out[15]: 'open'</div></div><div><br></div><div><br></div><div><br></div><div>Thanks,</div><div>Denis</div></div><div class="gmail_extra"><br><div class="gmail_quote">On Mon, Sep 26, 2016 at 9:19 AM, Henning Moeller <span dir="ltr"><<a href="mailto:HMoeller@comprion.com" target="_blank">HMoeller@comprion.com</a>></span> wrote:<br><blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex">
<div lang="DE" link="blue" vlink="purple">
<div>
<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri",sans-serif;color:#1f497d">Hi Denis,<u></u><u></u></span></p>
<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri",sans-serif;color:#1f497d"><u></u> <u></u></span></p>
<p class="MsoNormal"><span lang="EN-US" style="font-size:11.0pt;font-family:"Calibri",sans-serif;color:#1f497d">Thanks for your fast response. Sounds completely reasonable to me. And this has not been too much of an issue for me.<u></u><u></u></span></p>
<p class="MsoNormal"><span lang="EN-US" style="font-size:11.0pt;font-family:"Calibri",sans-serif;color:#1f497d"><u></u> <u></u></span></p>
<p class="MsoNormal"><span lang="EN-US" style="font-size:11.0pt;font-family:"Calibri",sans-serif;color:#1f497d">I got rid of the abstract base class simply by providing an “empty” implementation and using a non-abstract base class.
No need for meta classes any more. This way, I got rid of error messages. Great!<u></u><u></u></span></p>
<p class="MsoNormal"><span lang="EN-US" style="font-size:11.0pt;font-family:"Calibri",sans-serif;color:#1f497d"><u></u> <u></u></span></p>
<p class="MsoNormal"><span lang="EN-US" style="font-size:11.0pt;font-family:"Calibri",sans-serif;color:#1f497d">Unfortunately, there seem to be an issue when calling a virtual method inside the C# implementation. Even when overriding
this virtual method in Python, it’s still the base class’ implementation which is called.<u></u><u></u></span></p>
<p class="MsoNormal"><span lang="EN-US" style="font-size:11.0pt;font-family:"Calibri",sans-serif;color:#1f497d"><u></u> <u></u></span></p>
<p class="MsoNormal"><span lang="EN-US" style="font-size:11.0pt;font-family:"Calibri",sans-serif;color:#1f497d">See the new simple base class defined in C#:<u></u><u></u></span></p>
<p class="MsoNormal"><span lang="EN-US" style="font-size:11.0pt;font-family:"Calibri",sans-serif;color:#1f497d"><u></u> <u></u></span></p>
<p class="MsoNormal" style="text-autospace:none"><span lang="EN-US" style="font-size:9.5pt;font-family:Consolas;color:blue">namespace</span><span lang="EN-US" style="font-size:9.5pt;font-family:Consolas;color:black">
PythonBaseClass<u></u><u></u></span></p>
<p class="MsoNormal" style="text-autospace:none"><span lang="EN-US" style="font-size:9.5pt;font-family:Consolas;color:black">{<u></u><u></u></span></p>
<p class="MsoNormal" style="text-autospace:none"><span lang="EN-US" style="font-size:9.5pt;font-family:Consolas;color:black">
</span><span lang="EN-US" style="font-size:9.5pt;font-family:Consolas;color:blue">using</span><span lang="EN-US" style="font-size:9.5pt;font-family:Consolas;color:black"> System;<u></u><u></u></span></p>
<p class="MsoNormal" style="text-autospace:none"><span lang="EN-US" style="font-size:9.5pt;font-family:Consolas;color:black"><u></u> <u></u></span></p>
<p class="MsoNormal" style="text-autospace:none"><span lang="EN-US" style="font-size:9.5pt;font-family:Consolas;color:black">
</span><span lang="EN-US" style="font-size:9.5pt;font-family:Consolas;color:blue">public</span><span lang="EN-US" style="font-size:9.5pt;font-family:Consolas;color:black">
</span><span lang="EN-US" style="font-size:9.5pt;font-family:Consolas;color:blue">class</span><span lang="EN-US" style="font-size:9.5pt;font-family:Consolas;color:black">
</span><span lang="EN-US" style="font-size:9.5pt;font-family:Consolas;color:#2b91af">Door</span><span lang="EN-US" style="font-size:9.5pt;font-family:Consolas;color:black"><u></u><u></u></span></p>
<p class="MsoNormal" style="text-autospace:none"><span lang="EN-US" style="font-size:9.5pt;font-family:Consolas;color:black"> {<u></u><u></u></span></p>
<p class="MsoNormal" style="text-autospace:none"><span lang="EN-US" style="font-size:9.5pt;font-family:Consolas;color:black">
</span><span lang="EN-US" style="font-size:9.5pt;font-family:Consolas;color:blue">public</span><span lang="EN-US" style="font-size:9.5pt;font-family:Consolas;color:black">
</span><span lang="EN-US" style="font-size:9.5pt;font-family:Consolas;color:blue">virtual</span><span lang="EN-US" style="font-size:9.5pt;font-family:Consolas;color:black">
</span><span lang="EN-US" style="font-size:9.5pt;font-family:Consolas;color:blue">void</span><span lang="EN-US" style="font-size:9.5pt;font-family:Consolas;color:black"> Open()<u></u><u></u></span></p>
<p class="MsoNormal" style="text-autospace:none"><span lang="EN-US" style="font-size:9.5pt;font-family:Consolas;color:black"> {<u></u><u></u></span></p>
<p class="MsoNormal" style="text-autospace:none"><span lang="EN-US" style="font-size:9.5pt;font-family:Consolas;color:black">
</span><span lang="EN-US" style="font-size:9.5pt;font-family:Consolas;color:blue">if</span><span lang="EN-US" style="font-size:9.5pt;font-family:Consolas;color:black"> (!IsOpen())<u></u><u></u></span></p>
<p class="MsoNormal" style="text-autospace:none"><span lang="EN-US" style="font-size:9.5pt;font-family:Consolas;color:black"> Toggle();<u></u><u></u></span></p>
<p class="MsoNormal" style="text-autospace:none"><span lang="EN-US" style="font-size:9.5pt;font-family:Consolas;color:black"> }<u></u><u></u></span></p>
<p class="MsoNormal" style="text-autospace:none"><span lang="EN-US" style="font-size:9.5pt;font-family:Consolas;color:black"><u></u> <u></u></span></p>
<p class="MsoNormal" style="text-autospace:none"><span lang="EN-US" style="font-size:9.5pt;font-family:Consolas;color:black">
</span><span lang="EN-US" style="font-size:9.5pt;font-family:Consolas;color:blue">public</span><span lang="EN-US" style="font-size:9.5pt;font-family:Consolas;color:black">
</span><span lang="EN-US" style="font-size:9.5pt;font-family:Consolas;color:blue">virtual</span><span lang="EN-US" style="font-size:9.5pt;font-family:Consolas;color:black">
</span><span lang="EN-US" style="font-size:9.5pt;font-family:Consolas;color:blue">void</span><span lang="EN-US" style="font-size:9.5pt;font-family:Consolas;color:black"> Close()<u></u><u></u></span></p>
<p class="MsoNormal" style="text-autospace:none"><span lang="EN-US" style="font-size:9.5pt;font-family:Consolas;color:black"> {<u></u><u></u></span></p>
<p class="MsoNormal" style="text-autospace:none"><span lang="EN-US" style="font-size:9.5pt;font-family:Consolas;color:black">
</span><span lang="EN-US" style="font-size:9.5pt;font-family:Consolas;color:blue">if</span><span lang="EN-US" style="font-size:9.5pt;font-family:Consolas;color:black"> (IsOpen())<u></u><u></u></span></p>
<p class="MsoNormal" style="text-autospace:none"><span lang="EN-US" style="font-size:9.5pt;font-family:Consolas;color:black"> Toggle();<u></u><u></u></span></p>
<p class="MsoNormal" style="text-autospace:none"><span lang="EN-US" style="font-size:9.5pt;font-family:Consolas;color:black"> }<u></u><u></u></span></p>
<p class="MsoNormal" style="text-autospace:none"><span lang="EN-US" style="font-size:9.5pt;font-family:Consolas;color:black"><u></u> <u></u></span></p>
<p class="MsoNormal" style="text-autospace:none"><span lang="EN-US" style="font-size:9.5pt;font-family:Consolas;color:black">
</span><span lang="EN-US" style="font-size:9.5pt;font-family:Consolas;color:blue">public</span><span lang="EN-US" style="font-size:9.5pt;font-family:Consolas;color:black">
</span><span lang="EN-US" style="font-size:9.5pt;font-family:Consolas;color:blue">virtual</span><span lang="EN-US" style="font-size:9.5pt;font-family:Consolas;color:black">
</span><span lang="EN-US" style="font-size:9.5pt;font-family:Consolas;color:blue">bool</span><span lang="EN-US" style="font-size:9.5pt;font-family:Consolas;color:black"> IsOpen()<u></u><u></u></span></p>
<p class="MsoNormal" style="text-autospace:none"><span lang="EN-US" style="font-size:9.5pt;font-family:Consolas;color:black"> {<u></u><u></u></span></p>
<p class="MsoNormal" style="text-autospace:none"><span lang="EN-US" style="font-size:9.5pt;font-family:Consolas;color:black">
</span><span lang="EN-US" style="font-size:9.5pt;font-family:Consolas;color:#2b91af">Console</span><span lang="EN-US" style="font-size:9.5pt;font-family:Consolas;color:black">.WriteLine(</span><span lang="EN-US" style="font-size:9.5pt;font-family:Consolas;color:#a31515">"Door.<wbr>IsOpen()"</span><span lang="EN-US" style="font-size:9.5pt;font-family:Consolas;color:black">);<u></u><u></u></span></p>
<p class="MsoNormal" style="text-autospace:none"><span lang="EN-US" style="font-size:9.5pt;font-family:Consolas;color:black">
</span><span lang="EN-US" style="font-size:9.5pt;font-family:Consolas;color:blue">return</span><span lang="EN-US" style="font-size:9.5pt;font-family:Consolas;color:black">
</span><span lang="EN-US" style="font-size:9.5pt;font-family:Consolas;color:blue">false</span><span lang="EN-US" style="font-size:9.5pt;font-family:Consolas;color:black">;<u></u><u></u></span></p>
<p class="MsoNormal" style="text-autospace:none"><span lang="EN-US" style="font-size:9.5pt;font-family:Consolas;color:black"> }<u></u><u></u></span></p>
<p class="MsoNormal" style="text-autospace:none"><span lang="EN-US" style="font-size:9.5pt;font-family:Consolas;color:black"><u></u> <u></u></span></p>
<p class="MsoNormal" style="text-autospace:none"><span lang="EN-US" style="font-size:9.5pt;font-family:Consolas;color:black">
</span><span lang="EN-US" style="font-size:9.5pt;font-family:Consolas;color:blue">public</span><span lang="EN-US" style="font-size:9.5pt;font-family:Consolas;color:black">
</span><span lang="EN-US" style="font-size:9.5pt;font-family:Consolas;color:blue">virtual</span><span lang="EN-US" style="font-size:9.5pt;font-family:Consolas;color:black">
</span><span lang="EN-US" style="font-size:9.5pt;font-family:Consolas;color:blue">void</span><span lang="EN-US" style="font-size:9.5pt;font-family:Consolas;color:black"> Toggle()<u></u><u></u></span></p>
<p class="MsoNormal" style="text-autospace:none"><span lang="EN-US" style="font-size:9.5pt;font-family:Consolas;color:black"> {<u></u><u></u></span></p>
<p class="MsoNormal" style="text-autospace:none"><span lang="EN-US" style="font-size:9.5pt;font-family:Consolas;color:black">
</span><span lang="EN-US" style="font-size:9.5pt;font-family:Consolas;color:#2b91af">Console</span><span lang="EN-US" style="font-size:9.5pt;font-family:Consolas;color:black">.WriteLine(</span><span lang="EN-US" style="font-size:9.5pt;font-family:Consolas;color:#a31515">"Door.<wbr>Toggle()"</span><span lang="EN-US" style="font-size:9.5pt;font-family:Consolas;color:black">);<u></u><u></u></span></p>
<p class="MsoNormal" style="text-autospace:none"><span lang="EN-US" style="font-size:9.5pt;font-family:Consolas;color:black">
</span><span style="font-size:9.5pt;font-family:Consolas;color:black">}<u></u><u></u></span></p>
<p class="MsoNormal" style="text-autospace:none"><span style="font-size:9.5pt;font-family:Consolas;color:black"> }<u></u><u></u></span></p>
<p class="MsoNormal"><span style="font-size:9.5pt;font-family:Consolas;color:black">}<u></u><u></u></span></p>
<p class="MsoNormal"><span style="font-size:9.5pt;font-family:Consolas;color:black"><u></u> <u></u></span></p>
<p class="MsoNormal"><span lang="EN-US" style="font-size:11.0pt;font-family:"Calibri",sans-serif;color:#1f497d">The consuming Python code now looks like this:<u></u><u></u></span></p>
<p class="MsoNormal"><span lang="EN-US" style="font-size:9.5pt;font-family:Consolas;color:black"><u></u> <u></u></span></p>
<p class="MsoNormal"><span lang="EN-US" style="font-size:9.5pt;font-family:Consolas;color:blue">import clr<u></u><u></u></span></p>
<p class="MsoNormal"><span lang="EN-US" style="font-size:9.5pt;font-family:Consolas;color:blue">from PythonBaseClass import Door<u></u><u></u></span></p>
<p class="MsoNormal"><span lang="EN-US" style="font-size:9.5pt;font-family:Consolas;color:blue"><u></u> <u></u></span></p>
<p class="MsoNormal"><span lang="EN-US" style="font-size:9.5pt;font-family:Consolas;color:blue">class StringDoor(Door):<u></u><u></u></span></p>
<p class="MsoNormal"><span lang="EN-US" style="font-size:9.5pt;font-family:Consolas;color:blue"> def __init__(self):<u></u><u></u></span></p>
<p class="MsoNormal"><span lang="EN-US" style="font-size:9.5pt;font-family:Consolas;color:blue"> self.status = "closed"<u></u><u></u></span></p>
<p class="MsoNormal"><span lang="EN-US" style="font-size:9.5pt;font-family:Consolas;color:blue"><u></u> <u></u></span></p>
<p class="MsoNormal"><span lang="EN-US" style="font-size:9.5pt;font-family:Consolas;color:blue"> def IsOpen(self):<u></u><u></u></span></p>
<p class="MsoNormal"><span lang="EN-US" style="font-size:9.5pt;font-family:Consolas;color:blue"> print "StringDoor.IsOpen()"<u></u><u></u></span></p>
<p class="MsoNormal"><span lang="EN-US" style="font-size:9.5pt;font-family:Consolas;color:blue"> return self.status == "open"<u></u><u></u></span></p>
<p class="MsoNormal"><span lang="EN-US" style="font-size:9.5pt;font-family:Consolas;color:blue"><u></u> <u></u></span></p>
<p class="MsoNormal"><span lang="EN-US" style="font-size:9.5pt;font-family:Consolas;color:blue"> def Toggle(self):<u></u><u></u></span></p>
<p class="MsoNormal"><span lang="EN-US" style="font-size:9.5pt;font-family:Consolas;color:blue"> print "StringDoor.Toggle()"<u></u><u></u></span></p>
<p class="MsoNormal"><span lang="EN-US" style="font-size:9.5pt;font-family:Consolas;color:blue"> if self.status == "open":<u></u><u></u></span></p>
<p class="MsoNormal"><span lang="EN-US" style="font-size:9.5pt;font-family:Consolas;color:blue"> self.status = "closed"<u></u><u></u></span></p>
<p class="MsoNormal"><span lang="EN-US" style="font-size:9.5pt;font-family:Consolas;color:blue"> else:<u></u><u></u></span></p>
<p class="MsoNormal"><span lang="EN-US" style="font-size:9.5pt;font-family:Consolas;color:blue"> self.status = "open"<u></u><u></u></span></p>
<p class="MsoNormal"><span lang="EN-US" style="font-size:11.0pt;font-family:"Calibri",sans-serif;color:#1f497d"><u></u> <u></u></span></p>
<p class="MsoNormal"><span lang="EN-US" style="font-size:11.0pt;font-family:"Calibri",sans-serif;color:#1f497d">But the output does not look like expected:<u></u><u></u></span></p>
<p class="MsoNormal"><span lang="EN-US" style="font-size:11.0pt;font-family:"Calibri",sans-serif;color:#1f497d"><u></u> <u></u></span></p>
<p class="MsoNormal"><span lang="EN-US" style="font-size:9.5pt;font-family:Consolas;color:blue">Python 2.7.12 (v2.7.12:d33e0cf91556, Jun 27 2016, 15:19:22) [MSC v.1500 32 bit (Intel)] on win32<u></u><u></u></span></p>
<p class="MsoNormal"><span lang="EN-US" style="font-size:9.5pt;font-family:Consolas;color:blue">Type "help", "copyright", "credits" or "license" for more information.<u></u><u></u></span></p>
<p class="MsoNormal"><span lang="EN-US" style="font-size:9.5pt;font-family:Consolas;color:blue">>>> from PythonInheritedClass import StringDoor<u></u><u></u></span></p>
<p class="MsoNormal"><span lang="EN-US" style="font-size:9.5pt;font-family:Consolas;color:blue">>>> d = StringDoor()<u></u><u></u></span></p>
<p class="MsoNormal"><span lang="EN-US" style="font-size:9.5pt;font-family:Consolas;color:blue">>>> d.status<u></u><u></u></span></p>
<p class="MsoNormal"><span lang="EN-US" style="font-size:9.5pt;font-family:Consolas;color:blue">'closed'<u></u><u></u></span></p>
<p class="MsoNormal"><span lang="EN-US" style="font-size:9.5pt;font-family:Consolas;color:blue">>>> d.Open()<u></u><u></u></span></p>
<p class="MsoNormal"><b><span lang="EN-US" style="font-size:9.5pt;font-family:Consolas;color:#c55a11">Door.IsOpen()<u></u><u></u></span></b></p>
<p class="MsoNormal"><b><span lang="EN-US" style="font-size:9.5pt;font-family:Consolas;color:#c55a11">Door.Toggle()<u></u><u></u></span></b></p>
<p class="MsoNormal"><span lang="EN-US" style="font-size:9.5pt;font-family:Consolas;color:blue">>>> d.status<u></u><u></u></span></p>
<p class="MsoNormal"><b><span lang="EN-US" style="font-size:9.5pt;font-family:Consolas;color:#c55a11">'closed'<u></u><u></u></span></b></p>
<p class="MsoNormal"><span lang="EN-US" style="font-size:9.5pt;font-family:Consolas;color:blue">>>><u></u> <u></u></span></p>
<p class="MsoNormal"><span lang="EN-US" style="font-size:11.0pt;font-family:"Calibri",sans-serif;color:#1f497d"><u></u> <u></u></span></p>
<p class="MsoNormal"><span lang="EN-US" style="font-size:11.0pt;font-family:"Calibri",sans-serif;color:#1f497d">From my understanding, the output should rather read “</span><span lang="EN-US" style="font-size:11.0pt;font-family:Consolas;color:#1f497d">StringDoor.<something>()</span><span lang="EN-US" style="font-size:11.0pt;font-family:"Calibri",sans-serif;color:#1f497d">”
instead of “</span><span lang="EN-US" style="font-size:11.0pt;font-family:Consolas;color:#1f497d">Door.<something>()</span><span lang="EN-US" style="font-size:11.0pt;font-family:"Calibri",sans-serif;color:#1f497d">”.
Obviously, only the base implementation is called but the overridden methods are ignored.<u></u><u></u></span></p>
<p class="MsoNormal"><span lang="EN-US" style="font-size:11.0pt;font-family:"Calibri",sans-serif;color:#1f497d"><u></u> <u></u></span></p>
<p class="MsoNormal"><span lang="EN-US" style="font-size:11.0pt;font-family:"Calibri",sans-serif;color:#1f497d">Also a limitation of inheriting C# classes in pythonnet?<u></u><u></u></span></p>
<p class="MsoNormal"><span lang="EN-US" style="font-size:11.0pt;font-family:"Calibri",sans-serif;color:#1f497d"><u></u> <u></u></span></p>
<p class="MsoNormal"><span lang="EN-US" style="font-size:11.0pt;font-family:"Calibri",sans-serif;color:#1f497d">BR,<u></u><u></u></span></p>
<p class="MsoNormal"><span lang="EN-US" style="font-size:11.0pt;font-family:"Calibri",sans-serif;color:#1f497d"><u></u> <u></u></span></p>
<p class="MsoNormal"><span lang="EN-US" style="font-size:11.0pt;font-family:"Calibri",sans-serif;color:#1f497d">Henning<u></u><u></u></span></p>
<p class="MsoNormal"><span lang="EN-US" style="font-size:11.0pt;font-family:"Calibri",sans-serif;color:#1f497d"><u></u> <u></u></span></p>
<p class="MsoNormal"><b><span lang="EN-US" style="font-size:11.0pt;font-family:"Calibri",sans-serif">From:</span></b><span lang="EN-US" style="font-size:11.0pt;font-family:"Calibri",sans-serif"> PythonDotNet [mailto:<a href="mailto:pythondotnet-bounces%2Bhmoeller" target="_blank">pythondotnet-bounces+<wbr>hmoeller</a>=<a href="mailto:comprion.com@python.org" target="_blank">comprion.com@python.<wbr>org</a>]
<b>On Behalf Of </b>Denis Akhiyarov<br>
<b>Sent:</b> Donnerstag, 22. September 2016 19:38<br>
<b>To:</b> A list for users and developers of Python for .NET <<a href="mailto:pythondotnet@python.org" target="_blank">pythondotnet@python.org</a>><br>
<b>Subject:</b> Re: [Python.NET] Inheriting from abstract .NET class<u></u><u></u></span></p>
<p class="MsoNormal"><u></u> <u></u></p>
<div>
<p class="MsoNormal">You are not a "Python <span style="font-size:11.0pt;font-family:"Calibri",sans-serif">n00b</span>" based on metaclass usage!<u></u><u></u></p>
<div>
<p class="MsoNormal"><u></u> <u></u></p>
</div>
<div>
<p class="MsoNormal">My recommendation is to keep simple integration layer between CPython and .NET, hence metaclasses were/are not supported.<u></u><u></u></p>
</div>
<div>
<p class="MsoNormal"><u></u> <u></u></p>
</div>
<div>
<p class="MsoNormal">But contributions are welcome! Although I expect this to be a tremendous undertaking based on reviewing multiple sources.<u></u><u></u></p>
</div>
<div>
<p class="MsoNormal"><u></u> <u></u></p>
</div>
<div>
<p class="MsoNormal">Note that metaclass is a very different low-level concept from higher-level abstract classes in .NET, hence direct mapping (e.g. `.register()` ) is not feasible.<u></u><u></u></p>
</div>
<div>
<p class="MsoNormal"><u></u> <u></u></p>
</div>
<div>
<p class="MsoNormal">Thanks,<u></u><u></u></p>
</div>
<div>
<p class="MsoNormal">Denis<u></u><u></u></p>
</div>
</div>
<div>
<p class="MsoNormal"><u></u> <u></u></p>
<div>
<p class="MsoNormal">On Thu, Sep 22, 2016 at 10:04 AM, Henning Moeller <<a href="mailto:HMoeller@comprion.com" target="_blank">HMoeller@comprion.com</a>> wrote:<u></u><u></u></p>
<blockquote style="border:none;border-left:solid #cccccc 1.0pt;padding:0cm 0cm 0cm 6.0pt;margin-left:4.8pt;margin-right:0cm">
<div>
<div>
<p class="MsoNormal"><span lang="EN-US">Hello out there,</span><u></u><u></u></p>
<p class="MsoNormal"><span lang="EN-US"> </span><u></u><u></u></p>
<p class="MsoNormal"><span lang="EN-US">I’m trying to inherit from an abstract .NET base class in Python (2.7). I’m a Python n00b but from what I understood…</span><u></u><u></u></p>
<p class="MsoNormal"><span lang="EN-US"> </span><u></u><u></u></p>
<p class="MsoNormal"><span lang="EN-US">Here’s what I managed to do in Python only and which works fine:</span><u></u><u></u></p>
<p class="MsoNormal"><span lang="EN-US"> </span><u></u><u></u></p>
<p class="MsoNormal"><span lang="EN-US">[File: room.py] -------</span><u></u><u></u></p>
<p class="MsoNormal"><span lang="EN-US" style="font-size:9.5pt;font-family:Consolas">import abc</span><u></u><u></u></p>
<p class="MsoNormal"><span lang="EN-US" style="font-size:9.5pt;font-family:Consolas"> </span><u></u><u></u></p>
<p class="MsoNormal"><span lang="EN-US" style="font-size:9.5pt;font-family:Consolas">class Room(object):</span><u></u><u></u></p>
<p class="MsoNormal"><span lang="EN-US" style="font-size:9.5pt;font-family:Consolas"> def __init__(self, door):</span><u></u><u></u></p>
<p class="MsoNormal"><span lang="EN-US" style="font-size:9.5pt;font-family:Consolas"> self.door = door</span><u></u><u></u></p>
<p class="MsoNormal"><span lang="EN-US" style="font-size:9.5pt;font-family:Consolas"> </span><u></u><u></u></p>
<p class="MsoNormal"><span lang="EN-US" style="font-size:9.5pt;font-family:Consolas"> def open(self):</span><u></u><u></u></p>
<p class="MsoNormal"><span lang="EN-US" style="font-size:9.5pt;font-family:Consolas"> self.door.open()</span><u></u><u></u></p>
<p class="MsoNormal"><span lang="EN-US" style="font-size:9.5pt;font-family:Consolas"> </span><u></u><u></u></p>
<p class="MsoNormal"><span lang="EN-US" style="font-size:9.5pt;font-family:Consolas"> def close(self):</span><u></u><u></u></p>
<p class="MsoNormal"><span lang="EN-US" style="font-size:9.5pt;font-family:Consolas"> self.door.close()</span><u></u><u></u></p>
<p class="MsoNormal"><span lang="EN-US" style="font-size:9.5pt;font-family:Consolas"> </span><u></u><u></u></p>
<p class="MsoNormal"><span lang="EN-US" style="font-size:9.5pt;font-family:Consolas"> def is_open(self):</span><u></u><u></u></p>
<p class="MsoNormal"><span lang="EN-US" style="font-size:9.5pt;font-family:Consolas"> return self.door.is_open()</span><u></u><u></u></p>
<p class="MsoNormal"><span lang="EN-US" style="font-size:9.5pt;font-family:Consolas">
</span><u></u><u></u></p>
<p class="MsoNormal"><span lang="EN-US" style="font-size:9.5pt;font-family:Consolas">class Door(object):</span><u></u><u></u></p>
<p class="MsoNormal"><span lang="EN-US" style="font-size:9.5pt;font-family:Consolas"> __metaclass__ = abc.ABCMeta</span><u></u><u></u></p>
<p class="MsoNormal"><span lang="EN-US" style="font-size:9.5pt;font-family:Consolas">
</span><u></u><u></u></p>
<p class="MsoNormal"><span lang="EN-US" style="font-size:9.5pt;font-family:Consolas"> def open(self):</span><u></u><u></u></p>
<p class="MsoNormal"><span lang="EN-US" style="font-size:9.5pt;font-family:Consolas"> if not self.is_open():</span><u></u><u></u></p>
<p class="MsoNormal"><span lang="EN-US" style="font-size:9.5pt;font-family:Consolas"> self.toggle()</span><u></u><u></u></p>
<p class="MsoNormal"><span lang="EN-US" style="font-size:9.5pt;font-family:Consolas"> </span><u></u><u></u></p>
<p class="MsoNormal"><span lang="EN-US" style="font-size:9.5pt;font-family:Consolas"> def close(self):</span><u></u><u></u></p>
<p class="MsoNormal"><span lang="EN-US" style="font-size:9.5pt;font-family:Consolas"> if self.is_open():</span><u></u><u></u></p>
<p class="MsoNormal"><span lang="EN-US" style="font-size:9.5pt;font-family:Consolas"> self.toggle()</span><u></u><u></u></p>
<p class="MsoNormal"><span lang="EN-US" style="font-size:9.5pt;font-family:Consolas"> </span><u></u><u></u></p>
<p class="MsoNormal"><span lang="EN-US" style="font-size:9.5pt;font-family:Consolas"> @abc.abstractmethod</span><u></u><u></u></p>
<p class="MsoNormal"><span lang="EN-US" style="font-size:9.5pt;font-family:Consolas"> def is_open(self):</span><u></u><u></u></p>
<p class="MsoNormal"><span lang="EN-US" style="font-size:9.5pt;font-family:Consolas"> pass</span><u></u><u></u></p>
<p class="MsoNormal"><span lang="EN-US" style="font-size:9.5pt;font-family:Consolas"> </span><u></u><u></u></p>
<p class="MsoNormal"><span lang="EN-US" style="font-size:9.5pt;font-family:Consolas"> @abc.abstractmethod</span><u></u><u></u></p>
<p class="MsoNormal"><span lang="EN-US" style="font-size:9.5pt;font-family:Consolas"> def toggle(self):</span><u></u><u></u></p>
<p class="MsoNormal"><span lang="EN-US" style="font-size:9.5pt;font-family:Consolas"> pass</span><u></u><u></u></p>
<p class="MsoNormal"><span lang="EN-US" style="font-size:9.5pt;font-family:Consolas">
</span><u></u><u></u></p>
<p class="MsoNormal"><span lang="EN-US" style="font-size:9.5pt;font-family:Consolas">class StringDoor(Door):</span><u></u><u></u></p>
<p class="MsoNormal"><span lang="EN-US" style="font-size:9.5pt;font-family:Consolas"> def __init__(self):</span><u></u><u></u></p>
<p class="MsoNormal"><span lang="EN-US" style="font-size:9.5pt;font-family:Consolas"> self.status = "closed"</span><u></u><u></u></p>
<p class="MsoNormal"><span lang="EN-US" style="font-size:9.5pt;font-family:Consolas">
</span><u></u><u></u></p>
<p class="MsoNormal"><span lang="EN-US" style="font-size:9.5pt;font-family:Consolas"> def is_open(self):</span><u></u><u></u></p>
<p class="MsoNormal"><span lang="EN-US" style="font-size:9.5pt;font-family:Consolas"> return self.status == "open"</span><u></u><u></u></p>
<p class="MsoNormal"><span lang="EN-US" style="font-size:9.5pt;font-family:Consolas">
</span><u></u><u></u></p>
<p class="MsoNormal"><span lang="EN-US" style="font-size:9.5pt;font-family:Consolas"> def toggle(self):</span><u></u><u></u></p>
<p class="MsoNormal"><span lang="EN-US" style="font-size:9.5pt;font-family:Consolas"> if self.status == "open":</span><u></u><u></u></p>
<p class="MsoNormal"><span lang="EN-US" style="font-size:9.5pt;font-family:Consolas"> self.status = "closed"</span><u></u><u></u></p>
<p class="MsoNormal"><span lang="EN-US" style="font-size:9.5pt;font-family:Consolas"> else:</span><u></u><u></u></p>
<p class="MsoNormal"><span lang="EN-US" style="font-size:9.5pt;font-family:Consolas"> self.status = "open"</span><u></u><u></u></p>
<p class="MsoNormal"><span lang="EN-US" style="font-size:9.5pt;font-family:Consolas"> </span><u></u><u></u></p>
<p class="MsoNormal"><span lang="EN-US" style="font-size:9.5pt;font-family:Consolas">class BooleanDoor(Door):</span><u></u><u></u></p>
<p class="MsoNormal"><span lang="EN-US" style="font-size:9.5pt;font-family:Consolas"> def __init__(self):</span><u></u><u></u></p>
<p class="MsoNormal"><span lang="EN-US" style="font-size:9.5pt;font-family:Consolas"> self.status = True</span><u></u><u></u></p>
<p class="MsoNormal"><span lang="EN-US" style="font-size:9.5pt;font-family:Consolas"> </span><u></u><u></u></p>
<p class="MsoNormal"><span lang="EN-US" style="font-size:9.5pt;font-family:Consolas"> def is_open(self):</span><u></u><u></u></p>
<p class="MsoNormal"><span lang="EN-US" style="font-size:9.5pt;font-family:Consolas"> return self.status</span><u></u><u></u></p>
<p class="MsoNormal"><span lang="EN-US" style="font-size:9.5pt;font-family:Consolas">
</span><u></u><u></u></p>
<p class="MsoNormal"><span lang="EN-US" style="font-size:9.5pt;font-family:Consolas"> def toggle(self):</span><u></u><u></u></p>
<p class="MsoNormal"><span lang="EN-US" style="font-size:9.5pt;font-family:Consolas"> self.status = not (self.status)</span><u></u><u></u></p>
<p class="MsoNormal"><span lang="EN-US" style="font-size:9.5pt;font-family:Consolas"> </span><u></u><u></u></p>
<p class="MsoNormal"><span lang="EN-US" style="font-size:9.5pt;font-family:Consolas">Door.register(StringDoor)</span><u></u><u></u></p>
<p class="MsoNormal"><span lang="EN-US" style="font-size:9.5pt;font-family:Consolas">Door.register(BooleanDoor)</span><u></u><u></u></p>
<p class="MsoNormal"><span lang="EN-US">-------</span><u></u><u></u></p>
<p class="MsoNormal"><span lang="EN-US" style="font-size:9.0pt;font-family:"Courier New"">
</span><u></u><u></u></p>
<p class="MsoNormal"><span lang="EN-US">Now, all I did was to replace the abstract base class Door by a C# representation:</span><u></u><u></u></p>
<p class="MsoNormal"><span lang="EN-US" style="font-size:9.0pt;font-family:"Courier New""> </span><u></u><u></u></p>
<p class="MsoNormal"><span lang="EN-US">[File: PythonAbstractBaseClass.dll] -------</span><u></u><u></u></p>
<p class="MsoNormal" style="text-autospace:none">
<span lang="EN-US" style="font-size:9.5pt;font-family:Consolas;color:blue;background:white">namespace</span><span lang="EN-US" style="font-size:9.5pt;font-family:Consolas;color:black;background:white"> PythonAbstractBaseClass</span><u></u><u></u></p>
<p class="MsoNormal" style="text-autospace:none">
<span lang="EN-US" style="font-size:9.5pt;font-family:Consolas;color:black;background:white">{</span><u></u><u></u></p>
<p class="MsoNormal" style="text-autospace:none">
<span lang="EN-US" style="font-size:9.5pt;font-family:Consolas;color:black;background:white">
</span><span lang="EN-US" style="font-size:9.5pt;font-family:Consolas;color:blue;background:white">public</span><span lang="EN-US" style="font-size:9.5pt;font-family:Consolas;color:black;background:white">
</span><span lang="EN-US" style="font-size:9.5pt;font-family:Consolas;color:blue;background:white">abstract</span><span lang="EN-US" style="font-size:9.5pt;font-family:Consolas;color:black;background:white">
</span><span lang="EN-US" style="font-size:9.5pt;font-family:Consolas;color:blue;background:white">class</span><span lang="EN-US" style="font-size:9.5pt;font-family:Consolas;color:black;background:white">
</span><span lang="EN-US" style="font-size:9.5pt;font-family:Consolas;color:#2b91af;background:white">Door</span><u></u><u></u></p>
<p class="MsoNormal" style="text-autospace:none">
<span lang="EN-US" style="font-size:9.5pt;font-family:Consolas;color:black;background:white"> {</span><u></u><u></u></p>
<p class="MsoNormal" style="text-autospace:none">
<span lang="EN-US" style="font-size:9.5pt;font-family:Consolas;color:black;background:white">
</span><span lang="EN-US" style="font-size:9.5pt;font-family:Consolas;color:blue;background:white">public</span><span lang="EN-US" style="font-size:9.5pt;font-family:Consolas;color:black;background:white">
</span><span lang="EN-US" style="font-size:9.5pt;font-family:Consolas;color:blue;background:white">virtual</span><span lang="EN-US" style="font-size:9.5pt;font-family:Consolas;color:black;background:white">
</span><span lang="EN-US" style="font-size:9.5pt;font-family:Consolas;color:blue;background:white">void</span><span lang="EN-US" style="font-size:9.5pt;font-family:Consolas;color:black;background:white"> Open()</span><u></u><u></u></p>
<p class="MsoNormal" style="text-autospace:none">
<span lang="EN-US" style="font-size:9.5pt;font-family:Consolas;color:black;background:white"> {</span><u></u><u></u></p>
<p class="MsoNormal" style="text-autospace:none">
<span lang="EN-US" style="font-size:9.5pt;font-family:Consolas;color:black;background:white">
</span><span lang="EN-US" style="font-size:9.5pt;font-family:Consolas;color:blue;background:white">if</span><span lang="EN-US" style="font-size:9.5pt;font-family:Consolas;color:black;background:white"> (!IsOpen())</span><u></u><u></u></p>
<p class="MsoNormal" style="text-autospace:none">
<span lang="EN-US" style="font-size:9.5pt;font-family:Consolas;color:black;background:white"> Toggle();</span><u></u><u></u></p>
<p class="MsoNormal" style="text-autospace:none">
<span lang="EN-US" style="font-size:9.5pt;font-family:Consolas;color:black;background:white"> }</span><u></u><u></u></p>
<p class="MsoNormal" style="text-autospace:none">
<span lang="EN-US" style="font-size:9.5pt;font-family:Consolas;color:black;background:white"> </span><u></u><u></u></p>
<p class="MsoNormal" style="text-autospace:none">
<span lang="EN-US" style="font-size:9.5pt;font-family:Consolas;color:black;background:white">
</span><span lang="EN-US" style="font-size:9.5pt;font-family:Consolas;color:blue;background:white">public</span><span lang="EN-US" style="font-size:9.5pt;font-family:Consolas;color:black;background:white">
</span><span lang="EN-US" style="font-size:9.5pt;font-family:Consolas;color:blue;background:white">virtual</span><span lang="EN-US" style="font-size:9.5pt;font-family:Consolas;color:black;background:white">
</span><span lang="EN-US" style="font-size:9.5pt;font-family:Consolas;color:blue;background:white">void</span><span lang="EN-US" style="font-size:9.5pt;font-family:Consolas;color:black;background:white"> Close()</span><u></u><u></u></p>
<p class="MsoNormal" style="text-autospace:none">
<span lang="EN-US" style="font-size:9.5pt;font-family:Consolas;color:black;background:white"> {</span><u></u><u></u></p>
<p class="MsoNormal" style="text-autospace:none">
<span lang="EN-US" style="font-size:9.5pt;font-family:Consolas;color:black;background:white">
</span><span lang="EN-US" style="font-size:9.5pt;font-family:Consolas;color:blue;background:white">if</span><span lang="EN-US" style="font-size:9.5pt;font-family:Consolas;color:black;background:white"> (IsOpen())</span><u></u><u></u></p>
<p class="MsoNormal" style="text-autospace:none">
<span lang="EN-US" style="font-size:9.5pt;font-family:Consolas;color:black;background:white"> Toggle();</span><u></u><u></u></p>
<p class="MsoNormal" style="text-autospace:none">
<span lang="EN-US" style="font-size:9.5pt;font-family:Consolas;color:black;background:white"> }</span><u></u><u></u></p>
<p class="MsoNormal" style="text-autospace:none">
<span lang="EN-US" style="font-size:9.5pt;font-family:Consolas;color:black;background:white"> </span><u></u><u></u></p>
<p class="MsoNormal" style="text-autospace:none">
<span lang="EN-US" style="font-size:9.5pt;font-family:Consolas;color:black;background:white">
</span><span lang="EN-US" style="font-size:9.5pt;font-family:Consolas;color:blue;background:white">public</span><span lang="EN-US" style="font-size:9.5pt;font-family:Consolas;color:black;background:white">
</span><span lang="EN-US" style="font-size:9.5pt;font-family:Consolas;color:blue;background:white">abstract</span><span lang="EN-US" style="font-size:9.5pt;font-family:Consolas;color:black;background:white">
</span><span lang="EN-US" style="font-size:9.5pt;font-family:Consolas;color:blue;background:white">bool</span><span lang="EN-US" style="font-size:9.5pt;font-family:Consolas;color:black;background:white"> IsOpen();</span><u></u><u></u></p>
<p class="MsoNormal" style="text-autospace:none">
<span lang="EN-US" style="font-size:9.5pt;font-family:Consolas;color:black;background:white">
</span><span style="font-size:9.5pt;font-family:Consolas;color:blue;background:white">public</span><span style="font-size:9.5pt;font-family:Consolas;color:black;background:white">
</span><span style="font-size:9.5pt;font-family:Consolas;color:blue;background:white">abstract</span><span style="font-size:9.5pt;font-family:Consolas;color:black;background:white">
</span><span style="font-size:9.5pt;font-family:Consolas;color:blue;background:white">void</span><span style="font-size:9.5pt;font-family:Consolas;color:black;background:white"> Toggle();</span><u></u><u></u></p>
<p class="MsoNormal" style="text-autospace:none">
<span style="font-size:9.5pt;font-family:Consolas;color:black;background:white"> }</span><u></u><u></u></p>
<p class="MsoNormal" style="text-autospace:none">
<span style="font-size:9.5pt;font-family:Consolas;color:black;background:white">}</span><u></u><u></u></p>
<p class="MsoNormal"><span lang="EN-US">-------</span><u></u><u></u></p>
<p class="MsoNormal"><span lang="EN-US" style="font-size:9.0pt;font-family:"Courier New""> </span><u></u><u></u></p>
<p class="MsoNormal"><span lang="EN-US">Removing Door from the Python part and importing it from the .NET assembly instead, I end up with this:</span><u></u><u></u></p>
<p class="MsoNormal"><span lang="EN-US" style="font-size:9.0pt;font-family:"Courier New""> </span><u></u><u></u></p>
<p class="MsoNormal"><span lang="EN-US">[File: room2.py] -------</span><u></u><u></u></p>
<p class="MsoNormal"><span lang="EN-US" style="font-size:9.0pt;font-family:"Courier New"">import clr</span><u></u><u></u></p>
<p class="MsoNormal"><span lang="EN-US" style="font-size:9.0pt;font-family:"Courier New"">import abc</span><u></u><u></u></p>
<p class="MsoNormal"><span lang="EN-US" style="font-size:9.0pt;font-family:"Courier New"">from PythonAbstractBaseClass import Door</span><u></u><u></u></p>
<p class="MsoNormal"><span lang="EN-US" style="font-size:9.0pt;font-family:"Courier New""> </span><u></u><u></u></p>
<p class="MsoNormal"><span lang="EN-US" style="font-size:9.0pt;font-family:"Courier New"">class Room(object):</span><u></u><u></u></p>
<p class="MsoNormal"><span lang="EN-US" style="font-size:9.0pt;font-family:"Courier New""> def __init__(self, door):</span><u></u><u></u></p>
<p class="MsoNormal"><span lang="EN-US" style="font-size:9.0pt;font-family:"Courier New""> self.door = door</span><u></u><u></u></p>
<p class="MsoNormal"><span lang="EN-US" style="font-size:9.0pt;font-family:"Courier New""> </span><u></u><u></u></p>
<p class="MsoNormal"><span lang="EN-US" style="font-size:9.0pt;font-family:"Courier New""> def open(self):</span><u></u><u></u></p>
<p class="MsoNormal"><span lang="EN-US" style="font-size:9.0pt;font-family:"Courier New""> self.door.open()</span><u></u><u></u></p>
<p class="MsoNormal"><span lang="EN-US" style="font-size:9.0pt;font-family:"Courier New""> </span><u></u><u></u></p>
<p class="MsoNormal"><span lang="EN-US" style="font-size:9.0pt;font-family:"Courier New""> def close(self):</span><u></u><u></u></p>
<p class="MsoNormal"><span lang="EN-US" style="font-size:9.0pt;font-family:"Courier New""> self.door.close()</span><u></u><u></u></p>
<p class="MsoNormal"><span lang="EN-US" style="font-size:9.0pt;font-family:"Courier New""> </span><u></u><u></u></p>
<p class="MsoNormal"><span lang="EN-US" style="font-size:9.0pt;font-family:"Courier New""> def is_open(self):</span><u></u><u></u></p>
<p class="MsoNormal"><span lang="EN-US" style="font-size:9.0pt;font-family:"Courier New""> return self.door.is_open()</span><u></u><u></u></p>
<p class="MsoNormal"><span lang="EN-US" style="font-size:9.0pt;font-family:"Courier New"">
</span><u></u><u></u></p>
<p class="MsoNormal"><span lang="EN-US" style="font-size:9.0pt;font-family:"Courier New"">class StringDoor(Door):</span><u></u><u></u></p>
<p class="MsoNormal"><span lang="EN-US" style="font-size:9.0pt;font-family:"Courier New""> def __init__(self):</span><u></u><u></u></p>
<p class="MsoNormal"><span lang="EN-US" style="font-size:9.0pt;font-family:"Courier New""> self.status = "closed"</span><u></u><u></u></p>
<p class="MsoNormal"><span lang="EN-US" style="font-size:9.0pt;font-family:"Courier New"">
</span><u></u><u></u></p>
<p class="MsoNormal"><span lang="EN-US" style="font-size:9.0pt;font-family:"Courier New""> def is_open(self):</span><u></u><u></u></p>
<p class="MsoNormal"><span lang="EN-US" style="font-size:9.0pt;font-family:"Courier New""> return self.status == "open"</span><u></u><u></u></p>
<p class="MsoNormal"><span lang="EN-US" style="font-size:9.0pt;font-family:"Courier New"">
</span><u></u><u></u></p>
<p class="MsoNormal"><span lang="EN-US" style="font-size:9.0pt;font-family:"Courier New""> def toggle(self):</span><u></u><u></u></p>
<p class="MsoNormal"><span lang="EN-US" style="font-size:9.0pt;font-family:"Courier New""> if self.status == "open":</span><u></u><u></u></p>
<p class="MsoNormal"><span lang="EN-US" style="font-size:9.0pt;font-family:"Courier New""> self.status = "closed"</span><u></u><u></u></p>
<p class="MsoNormal"><span lang="EN-US" style="font-size:9.0pt;font-family:"Courier New""> else:</span><u></u><u></u></p>
<p class="MsoNormal"><span lang="EN-US" style="font-size:9.0pt;font-family:"Courier New""> self.status = "open"</span><u></u><u></u></p>
<p class="MsoNormal"><span lang="EN-US" style="font-size:9.0pt;font-family:"Courier New""> </span><u></u><u></u></p>
<p class="MsoNormal"><span lang="EN-US" style="font-size:9.0pt;font-family:"Courier New"">class BooleanDoor(Door):</span><u></u><u></u></p>
<p class="MsoNormal"><span lang="EN-US" style="font-size:9.0pt;font-family:"Courier New""> def __init__(self):</span><u></u><u></u></p>
<p class="MsoNormal"><span lang="EN-US" style="font-size:9.0pt;font-family:"Courier New""> self.status = True</span><u></u><u></u></p>
<p class="MsoNormal"><span lang="EN-US" style="font-size:9.0pt;font-family:"Courier New""> </span><u></u><u></u></p>
<p class="MsoNormal"><span lang="EN-US" style="font-size:9.0pt;font-family:"Courier New""> def is_open(self):</span><u></u><u></u></p>
<p class="MsoNormal"><span lang="EN-US" style="font-size:9.0pt;font-family:"Courier New""> return self.status</span><u></u><u></u></p>
<p class="MsoNormal"><span lang="EN-US" style="font-size:9.0pt;font-family:"Courier New"">
</span><u></u><u></u></p>
<p class="MsoNormal"><span lang="EN-US" style="font-size:9.0pt;font-family:"Courier New""> def toggle(self):</span><u></u><u></u></p>
<p class="MsoNormal"><span lang="EN-US" style="font-size:9.0pt;font-family:"Courier New""> self.status = not (self.status)</span><u></u><u></u></p>
<p class="MsoNormal"><span lang="EN-US" style="font-size:9.0pt;font-family:"Courier New""> </span><u></u><u></u></p>
<p class="MsoNormal"><span lang="EN-US" style="font-size:9.0pt;font-family:"Courier New"">Door.register(StringDoor)</span><u></u><u></u></p>
<p class="MsoNormal"><span lang="EN-US" style="font-size:9.0pt;font-family:"Courier New"">Door.register(BooleanDoor)</span><u></u><u></u></p>
<p class="MsoNormal"><span lang="EN-US">-------</span><u></u><u></u></p>
<p class="MsoNormal"><span lang="EN-US" style="font-size:9.0pt;font-family:"Courier New"">
</span><u></u><u></u></p>
<p class="MsoNormal"><span lang="EN-US">But this fails with the following error message:</span><u></u><u></u></p>
<p class="MsoNormal"><span lang="EN-US" style="font-size:9.0pt;font-family:"Courier New""> </span><u></u><u></u></p>
<p class="MsoNormal"><span lang="EN-US" style="font-size:9.0pt;font-family:"Courier New""> Door.register(StringDoor)</span><u></u><u></u></p>
<p class="MsoNormal"><span lang="EN-US" style="font-size:9.0pt;font-family:"Courier New"">AttributeError: type object 'Door' has no attribute 'register'</span><u></u><u></u></p>
<p class="MsoNormal"><span lang="EN-US" style="font-size:9.0pt;font-family:"Courier New""> </span><u></u><u></u></p>
<p class="MsoNormal"><span lang="EN-US">From what I understood about abc.ABCMeta, this metaclass contributes the ‘register’ method. It seems that abstract C# classes do not come with the same metaclass.
They instead come with metaclass “CLR Metatype” which obviously does not provide ‘register’.</span><u></u><u></u></p>
<p class="MsoNormal"><span lang="EN-US"> </span><u></u><u></u></p>
<p class="MsoNormal"><span lang="EN-US">But if I drop the call to ‘register’, on instantiating one of the derived classes, I receive the error message</span><u></u><u></u></p>
<p class="MsoNormal"><span lang="EN-US"> </span><u></u><u></u></p>
<p class="MsoNormal"><span lang="EN-US" style="font-size:9.0pt;font-family:"Courier New""> sdoor = StringDoor()</span><u></u><u></u></p>
<p class="MsoNormal"><span lang="EN-US" style="font-size:9.0pt;font-family:"Courier New"">TypeError: cannot instantiate abstract class</span><u></u><u></u></p>
<p class="MsoNormal"><span lang="EN-US" style="font-size:9.0pt;font-family:"Courier New""> </span><u></u><u></u></p>
<p class="MsoNormal"><span lang="EN-US">Is there a way to inherit from an abstract .NET class or is this is missing feature?</span><u></u><u></u></p>
<p class="MsoNormal"><span lang="EN-US"> </span><u></u><u></u></p>
<p class="MsoNormal"><span lang="EN-US">Thanks in advance,</span><u></u><u></u></p>
<p class="MsoNormal"><span lang="EN-US" style="color:#888888"> </span><span style="color:#888888"><u></u><u></u></span></p>
<p class="MsoNormal"><span lang="EN-US" style="color:#888888">Henning</span><span style="color:#888888"><u></u><u></u></span></p>
<p class="MsoNormal"><span lang="EN-US" style="color:#888888"> </span><span style="color:#888888"><u></u><u></u></span></p>
</div>
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<p class="MsoNormal"><br>
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<p class="MsoNormal"><u></u> <u></u></p>
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