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<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri",sans-serif;color:#1F497D;mso-fareast-language:EN-US">Hi Denis,<o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-size:11.0pt;font-family:"Calibri",sans-serif;color:#1F497D;mso-fareast-language:EN-US"><o:p> </o:p></span></p>
<p class="MsoNormal"><span lang="EN-US" style="font-size:11.0pt;font-family:"Calibri",sans-serif;color:#1F497D;mso-fareast-language:EN-US">Thanks for your fast response. Sounds completely reasonable to me. And this has not been too much of an issue for me.<o:p></o:p></span></p>
<p class="MsoNormal"><span lang="EN-US" style="font-size:11.0pt;font-family:"Calibri",sans-serif;color:#1F497D;mso-fareast-language:EN-US"><o:p> </o:p></span></p>
<p class="MsoNormal"><span lang="EN-US" style="font-size:11.0pt;font-family:"Calibri",sans-serif;color:#1F497D;mso-fareast-language:EN-US">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!<o:p></o:p></span></p>
<p class="MsoNormal"><span lang="EN-US" style="font-size:11.0pt;font-family:"Calibri",sans-serif;color:#1F497D;mso-fareast-language:EN-US"><o:p> </o:p></span></p>
<p class="MsoNormal"><span lang="EN-US" style="font-size:11.0pt;font-family:"Calibri",sans-serif;color:#1F497D;mso-fareast-language:EN-US">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.<o:p></o:p></span></p>
<p class="MsoNormal"><span lang="EN-US" style="font-size:11.0pt;font-family:"Calibri",sans-serif;color:#1F497D;mso-fareast-language:EN-US"><o:p> </o:p></span></p>
<p class="MsoNormal"><span lang="EN-US" style="font-size:11.0pt;font-family:"Calibri",sans-serif;color:#1F497D;mso-fareast-language:EN-US">See the new simple base class defined in C#:<o:p></o:p></span></p>
<p class="MsoNormal"><span lang="EN-US" style="font-size:11.0pt;font-family:"Calibri",sans-serif;color:#1F497D;mso-fareast-language:EN-US"><o:p> </o:p></span></p>
<p class="MsoNormal" style="text-autospace:none"><span lang="EN-US" style="font-size:9.5pt;font-family:Consolas;color:blue;mso-fareast-language:EN-US">namespace</span><span lang="EN-US" style="font-size:9.5pt;font-family:Consolas;color:black;mso-fareast-language:EN-US">
PythonBaseClass<o:p></o:p></span></p>
<p class="MsoNormal" style="text-autospace:none"><span lang="EN-US" style="font-size:9.5pt;font-family:Consolas;color:black;mso-fareast-language:EN-US">{<o:p></o:p></span></p>
<p class="MsoNormal" style="text-autospace:none"><span lang="EN-US" style="font-size:9.5pt;font-family:Consolas;color:black;mso-fareast-language:EN-US">
</span><span lang="EN-US" style="font-size:9.5pt;font-family:Consolas;color:blue;mso-fareast-language:EN-US">using</span><span lang="EN-US" style="font-size:9.5pt;font-family:Consolas;color:black;mso-fareast-language:EN-US"> System;<o:p></o:p></span></p>
<p class="MsoNormal" style="text-autospace:none"><span lang="EN-US" style="font-size:9.5pt;font-family:Consolas;color:black;mso-fareast-language:EN-US"><o:p> </o:p></span></p>
<p class="MsoNormal" style="text-autospace:none"><span lang="EN-US" style="font-size:9.5pt;font-family:Consolas;color:black;mso-fareast-language:EN-US">
</span><span lang="EN-US" style="font-size:9.5pt;font-family:Consolas;color:blue;mso-fareast-language:EN-US">public</span><span lang="EN-US" style="font-size:9.5pt;font-family:Consolas;color:black;mso-fareast-language:EN-US">
</span><span lang="EN-US" style="font-size:9.5pt;font-family:Consolas;color:blue;mso-fareast-language:EN-US">class</span><span lang="EN-US" style="font-size:9.5pt;font-family:Consolas;color:black;mso-fareast-language:EN-US">
</span><span lang="EN-US" style="font-size:9.5pt;font-family:Consolas;color:#2B91AF;mso-fareast-language:EN-US">Door</span><span lang="EN-US" style="font-size:9.5pt;font-family:Consolas;color:black;mso-fareast-language:EN-US"><o:p></o:p></span></p>
<p class="MsoNormal" style="text-autospace:none"><span lang="EN-US" style="font-size:9.5pt;font-family:Consolas;color:black;mso-fareast-language:EN-US"> {<o:p></o:p></span></p>
<p class="MsoNormal" style="text-autospace:none"><span lang="EN-US" style="font-size:9.5pt;font-family:Consolas;color:black;mso-fareast-language:EN-US">
</span><span lang="EN-US" style="font-size:9.5pt;font-family:Consolas;color:blue;mso-fareast-language:EN-US">public</span><span lang="EN-US" style="font-size:9.5pt;font-family:Consolas;color:black;mso-fareast-language:EN-US">
</span><span lang="EN-US" style="font-size:9.5pt;font-family:Consolas;color:blue;mso-fareast-language:EN-US">virtual</span><span lang="EN-US" style="font-size:9.5pt;font-family:Consolas;color:black;mso-fareast-language:EN-US">
</span><span lang="EN-US" style="font-size:9.5pt;font-family:Consolas;color:blue;mso-fareast-language:EN-US">void</span><span lang="EN-US" style="font-size:9.5pt;font-family:Consolas;color:black;mso-fareast-language:EN-US"> Open()<o:p></o:p></span></p>
<p class="MsoNormal" style="text-autospace:none"><span lang="EN-US" style="font-size:9.5pt;font-family:Consolas;color:black;mso-fareast-language:EN-US"> {<o:p></o:p></span></p>
<p class="MsoNormal" style="text-autospace:none"><span lang="EN-US" style="font-size:9.5pt;font-family:Consolas;color:black;mso-fareast-language:EN-US">
</span><span lang="EN-US" style="font-size:9.5pt;font-family:Consolas;color:blue;mso-fareast-language:EN-US">if</span><span lang="EN-US" style="font-size:9.5pt;font-family:Consolas;color:black;mso-fareast-language:EN-US"> (!IsOpen())<o:p></o:p></span></p>
<p class="MsoNormal" style="text-autospace:none"><span lang="EN-US" style="font-size:9.5pt;font-family:Consolas;color:black;mso-fareast-language:EN-US"> Toggle();<o:p></o:p></span></p>
<p class="MsoNormal" style="text-autospace:none"><span lang="EN-US" style="font-size:9.5pt;font-family:Consolas;color:black;mso-fareast-language:EN-US"> }<o:p></o:p></span></p>
<p class="MsoNormal" style="text-autospace:none"><span lang="EN-US" style="font-size:9.5pt;font-family:Consolas;color:black;mso-fareast-language:EN-US"><o:p> </o:p></span></p>
<p class="MsoNormal" style="text-autospace:none"><span lang="EN-US" style="font-size:9.5pt;font-family:Consolas;color:black;mso-fareast-language:EN-US">
</span><span lang="EN-US" style="font-size:9.5pt;font-family:Consolas;color:blue;mso-fareast-language:EN-US">public</span><span lang="EN-US" style="font-size:9.5pt;font-family:Consolas;color:black;mso-fareast-language:EN-US">
</span><span lang="EN-US" style="font-size:9.5pt;font-family:Consolas;color:blue;mso-fareast-language:EN-US">virtual</span><span lang="EN-US" style="font-size:9.5pt;font-family:Consolas;color:black;mso-fareast-language:EN-US">
</span><span lang="EN-US" style="font-size:9.5pt;font-family:Consolas;color:blue;mso-fareast-language:EN-US">void</span><span lang="EN-US" style="font-size:9.5pt;font-family:Consolas;color:black;mso-fareast-language:EN-US"> Close()<o:p></o:p></span></p>
<p class="MsoNormal" style="text-autospace:none"><span lang="EN-US" style="font-size:9.5pt;font-family:Consolas;color:black;mso-fareast-language:EN-US"> {<o:p></o:p></span></p>
<p class="MsoNormal" style="text-autospace:none"><span lang="EN-US" style="font-size:9.5pt;font-family:Consolas;color:black;mso-fareast-language:EN-US">
</span><span lang="EN-US" style="font-size:9.5pt;font-family:Consolas;color:blue;mso-fareast-language:EN-US">if</span><span lang="EN-US" style="font-size:9.5pt;font-family:Consolas;color:black;mso-fareast-language:EN-US"> (IsOpen())<o:p></o:p></span></p>
<p class="MsoNormal" style="text-autospace:none"><span lang="EN-US" style="font-size:9.5pt;font-family:Consolas;color:black;mso-fareast-language:EN-US"> Toggle();<o:p></o:p></span></p>
<p class="MsoNormal" style="text-autospace:none"><span lang="EN-US" style="font-size:9.5pt;font-family:Consolas;color:black;mso-fareast-language:EN-US"> }<o:p></o:p></span></p>
<p class="MsoNormal" style="text-autospace:none"><span lang="EN-US" style="font-size:9.5pt;font-family:Consolas;color:black;mso-fareast-language:EN-US"><o:p> </o:p></span></p>
<p class="MsoNormal" style="text-autospace:none"><span lang="EN-US" style="font-size:9.5pt;font-family:Consolas;color:black;mso-fareast-language:EN-US">
</span><span lang="EN-US" style="font-size:9.5pt;font-family:Consolas;color:blue;mso-fareast-language:EN-US">public</span><span lang="EN-US" style="font-size:9.5pt;font-family:Consolas;color:black;mso-fareast-language:EN-US">
</span><span lang="EN-US" style="font-size:9.5pt;font-family:Consolas;color:blue;mso-fareast-language:EN-US">virtual</span><span lang="EN-US" style="font-size:9.5pt;font-family:Consolas;color:black;mso-fareast-language:EN-US">
</span><span lang="EN-US" style="font-size:9.5pt;font-family:Consolas;color:blue;mso-fareast-language:EN-US">bool</span><span lang="EN-US" style="font-size:9.5pt;font-family:Consolas;color:black;mso-fareast-language:EN-US"> IsOpen()<o:p></o:p></span></p>
<p class="MsoNormal" style="text-autospace:none"><span lang="EN-US" style="font-size:9.5pt;font-family:Consolas;color:black;mso-fareast-language:EN-US"> {<o:p></o:p></span></p>
<p class="MsoNormal" style="text-autospace:none"><span lang="EN-US" style="font-size:9.5pt;font-family:Consolas;color:black;mso-fareast-language:EN-US">
</span><span lang="EN-US" style="font-size:9.5pt;font-family:Consolas;color:#2B91AF;mso-fareast-language:EN-US">Console</span><span lang="EN-US" style="font-size:9.5pt;font-family:Consolas;color:black;mso-fareast-language:EN-US">.WriteLine(</span><span lang="EN-US" style="font-size:9.5pt;font-family:Consolas;color:#A31515;mso-fareast-language:EN-US">"Door.IsOpen()"</span><span lang="EN-US" style="font-size:9.5pt;font-family:Consolas;color:black;mso-fareast-language:EN-US">);<o:p></o:p></span></p>
<p class="MsoNormal" style="text-autospace:none"><span lang="EN-US" style="font-size:9.5pt;font-family:Consolas;color:black;mso-fareast-language:EN-US">
</span><span lang="EN-US" style="font-size:9.5pt;font-family:Consolas;color:blue;mso-fareast-language:EN-US">return</span><span lang="EN-US" style="font-size:9.5pt;font-family:Consolas;color:black;mso-fareast-language:EN-US">
</span><span lang="EN-US" style="font-size:9.5pt;font-family:Consolas;color:blue;mso-fareast-language:EN-US">false</span><span lang="EN-US" style="font-size:9.5pt;font-family:Consolas;color:black;mso-fareast-language:EN-US">;<o:p></o:p></span></p>
<p class="MsoNormal" style="text-autospace:none"><span lang="EN-US" style="font-size:9.5pt;font-family:Consolas;color:black;mso-fareast-language:EN-US"> }<o:p></o:p></span></p>
<p class="MsoNormal" style="text-autospace:none"><span lang="EN-US" style="font-size:9.5pt;font-family:Consolas;color:black;mso-fareast-language:EN-US"><o:p> </o:p></span></p>
<p class="MsoNormal" style="text-autospace:none"><span lang="EN-US" style="font-size:9.5pt;font-family:Consolas;color:black;mso-fareast-language:EN-US">
</span><span lang="EN-US" style="font-size:9.5pt;font-family:Consolas;color:blue;mso-fareast-language:EN-US">public</span><span lang="EN-US" style="font-size:9.5pt;font-family:Consolas;color:black;mso-fareast-language:EN-US">
</span><span lang="EN-US" style="font-size:9.5pt;font-family:Consolas;color:blue;mso-fareast-language:EN-US">virtual</span><span lang="EN-US" style="font-size:9.5pt;font-family:Consolas;color:black;mso-fareast-language:EN-US">
</span><span lang="EN-US" style="font-size:9.5pt;font-family:Consolas;color:blue;mso-fareast-language:EN-US">void</span><span lang="EN-US" style="font-size:9.5pt;font-family:Consolas;color:black;mso-fareast-language:EN-US"> Toggle()<o:p></o:p></span></p>
<p class="MsoNormal" style="text-autospace:none"><span lang="EN-US" style="font-size:9.5pt;font-family:Consolas;color:black;mso-fareast-language:EN-US"> {<o:p></o:p></span></p>
<p class="MsoNormal" style="text-autospace:none"><span lang="EN-US" style="font-size:9.5pt;font-family:Consolas;color:black;mso-fareast-language:EN-US">
</span><span lang="EN-US" style="font-size:9.5pt;font-family:Consolas;color:#2B91AF;mso-fareast-language:EN-US">Console</span><span lang="EN-US" style="font-size:9.5pt;font-family:Consolas;color:black;mso-fareast-language:EN-US">.WriteLine(</span><span lang="EN-US" style="font-size:9.5pt;font-family:Consolas;color:#A31515;mso-fareast-language:EN-US">"Door.Toggle()"</span><span lang="EN-US" style="font-size:9.5pt;font-family:Consolas;color:black;mso-fareast-language:EN-US">);<o:p></o:p></span></p>
<p class="MsoNormal" style="text-autospace:none"><span lang="EN-US" style="font-size:9.5pt;font-family:Consolas;color:black;mso-fareast-language:EN-US">
</span><span style="font-size:9.5pt;font-family:Consolas;color:black;mso-fareast-language:EN-US">}<o:p></o:p></span></p>
<p class="MsoNormal" style="text-autospace:none"><span style="font-size:9.5pt;font-family:Consolas;color:black;mso-fareast-language:EN-US"> }<o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-size:9.5pt;font-family:Consolas;color:black;mso-fareast-language:EN-US">}<o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-size:9.5pt;font-family:Consolas;color:black;mso-fareast-language:EN-US"><o:p> </o:p></span></p>
<p class="MsoNormal"><span lang="EN-US" style="font-size:11.0pt;font-family:"Calibri",sans-serif;color:#1F497D;mso-fareast-language:EN-US">The consuming Python code now looks like this:<o:p></o:p></span></p>
<p class="MsoNormal"><span lang="EN-US" style="font-size:9.5pt;font-family:Consolas;color:black;mso-fareast-language:EN-US"><o:p> </o:p></span></p>
<p class="MsoNormal"><span lang="EN-US" style="font-size:9.5pt;font-family:Consolas;color:blue;mso-fareast-language:EN-US">import clr<o:p></o:p></span></p>
<p class="MsoNormal"><span lang="EN-US" style="font-size:9.5pt;font-family:Consolas;color:blue;mso-fareast-language:EN-US">from PythonBaseClass import Door<o:p></o:p></span></p>
<p class="MsoNormal"><span lang="EN-US" style="font-size:9.5pt;font-family:Consolas;color:blue;mso-fareast-language:EN-US"><o:p> </o:p></span></p>
<p class="MsoNormal"><span lang="EN-US" style="font-size:9.5pt;font-family:Consolas;color:blue;mso-fareast-language:EN-US">class StringDoor(Door):<o:p></o:p></span></p>
<p class="MsoNormal"><span lang="EN-US" style="font-size:9.5pt;font-family:Consolas;color:blue;mso-fareast-language:EN-US"> def __init__(self):<o:p></o:p></span></p>
<p class="MsoNormal"><span lang="EN-US" style="font-size:9.5pt;font-family:Consolas;color:blue;mso-fareast-language:EN-US"> self.status = "closed"<o:p></o:p></span></p>
<p class="MsoNormal"><span lang="EN-US" style="font-size:9.5pt;font-family:Consolas;color:blue;mso-fareast-language:EN-US"><o:p> </o:p></span></p>
<p class="MsoNormal"><span lang="EN-US" style="font-size:9.5pt;font-family:Consolas;color:blue;mso-fareast-language:EN-US"> def IsOpen(self):<o:p></o:p></span></p>
<p class="MsoNormal"><span lang="EN-US" style="font-size:9.5pt;font-family:Consolas;color:blue;mso-fareast-language:EN-US"> print "StringDoor.IsOpen()"<o:p></o:p></span></p>
<p class="MsoNormal"><span lang="EN-US" style="font-size:9.5pt;font-family:Consolas;color:blue;mso-fareast-language:EN-US"> return self.status == "open"<o:p></o:p></span></p>
<p class="MsoNormal"><span lang="EN-US" style="font-size:9.5pt;font-family:Consolas;color:blue;mso-fareast-language:EN-US"><o:p> </o:p></span></p>
<p class="MsoNormal"><span lang="EN-US" style="font-size:9.5pt;font-family:Consolas;color:blue;mso-fareast-language:EN-US"> def Toggle(self):<o:p></o:p></span></p>
<p class="MsoNormal"><span lang="EN-US" style="font-size:9.5pt;font-family:Consolas;color:blue;mso-fareast-language:EN-US"> print "StringDoor.Toggle()"<o:p></o:p></span></p>
<p class="MsoNormal"><span lang="EN-US" style="font-size:9.5pt;font-family:Consolas;color:blue;mso-fareast-language:EN-US"> if self.status == "open":<o:p></o:p></span></p>
<p class="MsoNormal"><span lang="EN-US" style="font-size:9.5pt;font-family:Consolas;color:blue;mso-fareast-language:EN-US"> self.status = "closed"<o:p></o:p></span></p>
<p class="MsoNormal"><span lang="EN-US" style="font-size:9.5pt;font-family:Consolas;color:blue;mso-fareast-language:EN-US"> else:<o:p></o:p></span></p>
<p class="MsoNormal"><span lang="EN-US" style="font-size:9.5pt;font-family:Consolas;color:blue;mso-fareast-language:EN-US"> self.status = "open"<o:p></o:p></span></p>
<p class="MsoNormal"><span lang="EN-US" style="font-size:11.0pt;font-family:"Calibri",sans-serif;color:#1F497D;mso-fareast-language:EN-US"><o:p> </o:p></span></p>
<p class="MsoNormal"><span lang="EN-US" style="font-size:11.0pt;font-family:"Calibri",sans-serif;color:#1F497D;mso-fareast-language:EN-US">But the output does not look like expected:<o:p></o:p></span></p>
<p class="MsoNormal"><span lang="EN-US" style="font-size:11.0pt;font-family:"Calibri",sans-serif;color:#1F497D;mso-fareast-language:EN-US"><o:p> </o:p></span></p>
<p class="MsoNormal"><span lang="EN-US" style="font-size:9.5pt;font-family:Consolas;color:blue;mso-fareast-language:EN-US">Python 2.7.12 (v2.7.12:d33e0cf91556, Jun 27 2016, 15:19:22) [MSC v.1500 32 bit (Intel)] on win32<o:p></o:p></span></p>
<p class="MsoNormal"><span lang="EN-US" style="font-size:9.5pt;font-family:Consolas;color:blue;mso-fareast-language:EN-US">Type "help", "copyright", "credits" or "license" for more information.<o:p></o:p></span></p>
<p class="MsoNormal"><span lang="EN-US" style="font-size:9.5pt;font-family:Consolas;color:blue;mso-fareast-language:EN-US">>>> from PythonInheritedClass import StringDoor<o:p></o:p></span></p>
<p class="MsoNormal"><span lang="EN-US" style="font-size:9.5pt;font-family:Consolas;color:blue;mso-fareast-language:EN-US">>>> d = StringDoor()<o:p></o:p></span></p>
<p class="MsoNormal"><span lang="EN-US" style="font-size:9.5pt;font-family:Consolas;color:blue;mso-fareast-language:EN-US">>>> d.status<o:p></o:p></span></p>
<p class="MsoNormal"><span lang="EN-US" style="font-size:9.5pt;font-family:Consolas;color:blue;mso-fareast-language:EN-US">'closed'<o:p></o:p></span></p>
<p class="MsoNormal"><span lang="EN-US" style="font-size:9.5pt;font-family:Consolas;color:blue;mso-fareast-language:EN-US">>>> d.Open()<o:p></o:p></span></p>
<p class="MsoNormal"><b><span lang="EN-US" style="font-size:9.5pt;font-family:Consolas;color:#C55A11;mso-style-textfill-fill-color:#C55A11;mso-style-textfill-fill-alpha:100.0%;mso-fareast-language:EN-US">Door.IsOpen()<o:p></o:p></span></b></p>
<p class="MsoNormal"><b><span lang="EN-US" style="font-size:9.5pt;font-family:Consolas;color:#C55A11;mso-style-textfill-fill-color:#C55A11;mso-style-textfill-fill-alpha:100.0%;mso-fareast-language:EN-US">Door.Toggle()<o:p></o:p></span></b></p>
<p class="MsoNormal"><span lang="EN-US" style="font-size:9.5pt;font-family:Consolas;color:blue;mso-fareast-language:EN-US">>>> d.status<o:p></o:p></span></p>
<p class="MsoNormal"><b><span lang="EN-US" style="font-size:9.5pt;font-family:Consolas;color:#C55A11;mso-style-textfill-fill-color:#C55A11;mso-style-textfill-fill-alpha:100.0%;mso-fareast-language:EN-US">'closed'<o:p></o:p></span></b></p>
<p class="MsoNormal"><span lang="EN-US" style="font-size:9.5pt;font-family:Consolas;color:blue;mso-fareast-language:EN-US">>>><o:p> </o:p></span></p>
<p class="MsoNormal"><span lang="EN-US" style="font-size:11.0pt;font-family:"Calibri",sans-serif;color:#1F497D;mso-fareast-language:EN-US"><o:p> </o:p></span></p>
<p class="MsoNormal"><span lang="EN-US" style="font-size:11.0pt;font-family:"Calibri",sans-serif;color:#1F497D;mso-fareast-language:EN-US">From my understanding, the output should rather read “</span><span lang="EN-US" style="font-size:11.0pt;font-family:Consolas;color:#1F497D;mso-fareast-language:EN-US">StringDoor.<something>()</span><span lang="EN-US" style="font-size:11.0pt;font-family:"Calibri",sans-serif;color:#1F497D;mso-fareast-language:EN-US">”
instead of “</span><span lang="EN-US" style="font-size:11.0pt;font-family:Consolas;color:#1F497D;mso-fareast-language:EN-US">Door.<something>()</span><span lang="EN-US" style="font-size:11.0pt;font-family:"Calibri",sans-serif;color:#1F497D;mso-fareast-language:EN-US">”.
Obviously, only the base implementation is called but the overridden methods are ignored.<o:p></o:p></span></p>
<p class="MsoNormal"><span lang="EN-US" style="font-size:11.0pt;font-family:"Calibri",sans-serif;color:#1F497D;mso-fareast-language:EN-US"><o:p> </o:p></span></p>
<p class="MsoNormal"><span lang="EN-US" style="font-size:11.0pt;font-family:"Calibri",sans-serif;color:#1F497D;mso-fareast-language:EN-US">Also a limitation of inheriting C# classes in pythonnet?<o:p></o:p></span></p>
<p class="MsoNormal"><span lang="EN-US" style="font-size:11.0pt;font-family:"Calibri",sans-serif;color:#1F497D;mso-fareast-language:EN-US"><o:p> </o:p></span></p>
<p class="MsoNormal"><span lang="EN-US" style="font-size:11.0pt;font-family:"Calibri",sans-serif;color:#1F497D;mso-fareast-language:EN-US">BR,<o:p></o:p></span></p>
<p class="MsoNormal"><span lang="EN-US" style="font-size:11.0pt;font-family:"Calibri",sans-serif;color:#1F497D;mso-fareast-language:EN-US"><o:p> </o:p></span></p>
<p class="MsoNormal"><span lang="EN-US" style="font-size:11.0pt;font-family:"Calibri",sans-serif;color:#1F497D;mso-fareast-language:EN-US">Henning<o:p></o:p></span></p>
<p class="MsoNormal"><span lang="EN-US" style="font-size:11.0pt;font-family:"Calibri",sans-serif;color:#1F497D;mso-fareast-language:EN-US"><o:p> </o:p></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:pythondotnet-bounces+hmoeller=comprion.com@python.org]
<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 <pythondotnet@python.org><br>
<b>Subject:</b> Re: [Python.NET] Inheriting from abstract .NET class<o:p></o:p></span></p>
<p class="MsoNormal"><o:p> </o:p></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!<o:p></o:p></p>
<div>
<p class="MsoNormal"><o:p> </o:p></p>
</div>
<div>
<p class="MsoNormal">My recommendation is to keep simple integration layer between CPython and .NET, hence metaclasses were/are not supported.<o:p></o:p></p>
</div>
<div>
<p class="MsoNormal"><o:p> </o:p></p>
</div>
<div>
<p class="MsoNormal">But contributions are welcome! Although I expect this to be a tremendous undertaking based on reviewing multiple sources.<o:p></o:p></p>
</div>
<div>
<p class="MsoNormal"><o:p> </o:p></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.<o:p></o:p></p>
</div>
<div>
<p class="MsoNormal"><o:p> </o:p></p>
</div>
<div>
<p class="MsoNormal">Thanks,<o:p></o:p></p>
</div>
<div>
<p class="MsoNormal">Denis<o:p></o:p></p>
</div>
</div>
<div>
<p class="MsoNormal"><o:p> </o:p></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:<o:p></o:p></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" style="mso-margin-top-alt:auto;mso-margin-bottom-alt:auto"><span lang="EN-US">Hello out there,</span><o:p></o:p></p>
<p class="MsoNormal" style="mso-margin-top-alt:auto;mso-margin-bottom-alt:auto"><span lang="EN-US"> </span><o:p></o:p></p>
<p class="MsoNormal" style="mso-margin-top-alt:auto;mso-margin-bottom-alt:auto"><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><o:p></o:p></p>
<p class="MsoNormal" style="mso-margin-top-alt:auto;mso-margin-bottom-alt:auto"><span lang="EN-US"> </span><o:p></o:p></p>
<p class="MsoNormal" style="mso-margin-top-alt:auto;mso-margin-bottom-alt:auto"><span lang="EN-US">Here’s what I managed to do in Python only and which works fine:</span><o:p></o:p></p>
<p class="MsoNormal" style="mso-margin-top-alt:auto;mso-margin-bottom-alt:auto"><span lang="EN-US"> </span><o:p></o:p></p>
<p class="MsoNormal" style="mso-margin-top-alt:auto;mso-margin-bottom-alt:auto"><span lang="EN-US">[File: room.py] -------</span><o:p></o:p></p>
<p class="MsoNormal" style="mso-margin-top-alt:auto;mso-margin-bottom-alt:auto"><span lang="EN-US" style="font-size:9.5pt;font-family:Consolas">import abc</span><o:p></o:p></p>
<p class="MsoNormal" style="mso-margin-top-alt:auto;mso-margin-bottom-alt:auto"><span lang="EN-US" style="font-size:9.5pt;font-family:Consolas"> </span><o:p></o:p></p>
<p class="MsoNormal" style="mso-margin-top-alt:auto;mso-margin-bottom-alt:auto"><span lang="EN-US" style="font-size:9.5pt;font-family:Consolas">class Room(object):</span><o:p></o:p></p>
<p class="MsoNormal" style="mso-margin-top-alt:auto;mso-margin-bottom-alt:auto"><span lang="EN-US" style="font-size:9.5pt;font-family:Consolas"> def __init__(self, door):</span><o:p></o:p></p>
<p class="MsoNormal" style="mso-margin-top-alt:auto;mso-margin-bottom-alt:auto"><span lang="EN-US" style="font-size:9.5pt;font-family:Consolas"> self.door = door</span><o:p></o:p></p>
<p class="MsoNormal" style="mso-margin-top-alt:auto;mso-margin-bottom-alt:auto"><span lang="EN-US" style="font-size:9.5pt;font-family:Consolas"> </span><o:p></o:p></p>
<p class="MsoNormal" style="mso-margin-top-alt:auto;mso-margin-bottom-alt:auto"><span lang="EN-US" style="font-size:9.5pt;font-family:Consolas"> def open(self):</span><o:p></o:p></p>
<p class="MsoNormal" style="mso-margin-top-alt:auto;mso-margin-bottom-alt:auto"><span lang="EN-US" style="font-size:9.5pt;font-family:Consolas"> self.door.open()</span><o:p></o:p></p>
<p class="MsoNormal" style="mso-margin-top-alt:auto;mso-margin-bottom-alt:auto"><span lang="EN-US" style="font-size:9.5pt;font-family:Consolas"> </span><o:p></o:p></p>
<p class="MsoNormal" style="mso-margin-top-alt:auto;mso-margin-bottom-alt:auto"><span lang="EN-US" style="font-size:9.5pt;font-family:Consolas"> def close(self):</span><o:p></o:p></p>
<p class="MsoNormal" style="mso-margin-top-alt:auto;mso-margin-bottom-alt:auto"><span lang="EN-US" style="font-size:9.5pt;font-family:Consolas"> self.door.close()</span><o:p></o:p></p>
<p class="MsoNormal" style="mso-margin-top-alt:auto;mso-margin-bottom-alt:auto"><span lang="EN-US" style="font-size:9.5pt;font-family:Consolas"> </span><o:p></o:p></p>
<p class="MsoNormal" style="mso-margin-top-alt:auto;mso-margin-bottom-alt:auto"><span lang="EN-US" style="font-size:9.5pt;font-family:Consolas"> def is_open(self):</span><o:p></o:p></p>
<p class="MsoNormal" style="mso-margin-top-alt:auto;mso-margin-bottom-alt:auto"><span lang="EN-US" style="font-size:9.5pt;font-family:Consolas"> return self.door.is_open()</span><o:p></o:p></p>
<p class="MsoNormal" style="mso-margin-top-alt:auto;mso-margin-bottom-alt:auto"><span lang="EN-US" style="font-size:9.5pt;font-family:Consolas">
</span><o:p></o:p></p>
<p class="MsoNormal" style="mso-margin-top-alt:auto;mso-margin-bottom-alt:auto"><span lang="EN-US" style="font-size:9.5pt;font-family:Consolas">class Door(object):</span><o:p></o:p></p>
<p class="MsoNormal" style="mso-margin-top-alt:auto;mso-margin-bottom-alt:auto"><span lang="EN-US" style="font-size:9.5pt;font-family:Consolas"> __metaclass__ = abc.ABCMeta</span><o:p></o:p></p>
<p class="MsoNormal" style="mso-margin-top-alt:auto;mso-margin-bottom-alt:auto"><span lang="EN-US" style="font-size:9.5pt;font-family:Consolas">
</span><o:p></o:p></p>
<p class="MsoNormal" style="mso-margin-top-alt:auto;mso-margin-bottom-alt:auto"><span lang="EN-US" style="font-size:9.5pt;font-family:Consolas"> def open(self):</span><o:p></o:p></p>
<p class="MsoNormal" style="mso-margin-top-alt:auto;mso-margin-bottom-alt:auto"><span lang="EN-US" style="font-size:9.5pt;font-family:Consolas"> if not self.is_open():</span><o:p></o:p></p>
<p class="MsoNormal" style="mso-margin-top-alt:auto;mso-margin-bottom-alt:auto"><span lang="EN-US" style="font-size:9.5pt;font-family:Consolas"> self.toggle()</span><o:p></o:p></p>
<p class="MsoNormal" style="mso-margin-top-alt:auto;mso-margin-bottom-alt:auto"><span lang="EN-US" style="font-size:9.5pt;font-family:Consolas"> </span><o:p></o:p></p>
<p class="MsoNormal" style="mso-margin-top-alt:auto;mso-margin-bottom-alt:auto"><span lang="EN-US" style="font-size:9.5pt;font-family:Consolas"> def close(self):</span><o:p></o:p></p>
<p class="MsoNormal" style="mso-margin-top-alt:auto;mso-margin-bottom-alt:auto"><span lang="EN-US" style="font-size:9.5pt;font-family:Consolas"> if self.is_open():</span><o:p></o:p></p>
<p class="MsoNormal" style="mso-margin-top-alt:auto;mso-margin-bottom-alt:auto"><span lang="EN-US" style="font-size:9.5pt;font-family:Consolas"> self.toggle()</span><o:p></o:p></p>
<p class="MsoNormal" style="mso-margin-top-alt:auto;mso-margin-bottom-alt:auto"><span lang="EN-US" style="font-size:9.5pt;font-family:Consolas"> </span><o:p></o:p></p>
<p class="MsoNormal" style="mso-margin-top-alt:auto;mso-margin-bottom-alt:auto"><span lang="EN-US" style="font-size:9.5pt;font-family:Consolas"> @abc.abstractmethod</span><o:p></o:p></p>
<p class="MsoNormal" style="mso-margin-top-alt:auto;mso-margin-bottom-alt:auto"><span lang="EN-US" style="font-size:9.5pt;font-family:Consolas"> def is_open(self):</span><o:p></o:p></p>
<p class="MsoNormal" style="mso-margin-top-alt:auto;mso-margin-bottom-alt:auto"><span lang="EN-US" style="font-size:9.5pt;font-family:Consolas"> pass</span><o:p></o:p></p>
<p class="MsoNormal" style="mso-margin-top-alt:auto;mso-margin-bottom-alt:auto"><span lang="EN-US" style="font-size:9.5pt;font-family:Consolas"> </span><o:p></o:p></p>
<p class="MsoNormal" style="mso-margin-top-alt:auto;mso-margin-bottom-alt:auto"><span lang="EN-US" style="font-size:9.5pt;font-family:Consolas"> @abc.abstractmethod</span><o:p></o:p></p>
<p class="MsoNormal" style="mso-margin-top-alt:auto;mso-margin-bottom-alt:auto"><span lang="EN-US" style="font-size:9.5pt;font-family:Consolas"> def toggle(self):</span><o:p></o:p></p>
<p class="MsoNormal" style="mso-margin-top-alt:auto;mso-margin-bottom-alt:auto"><span lang="EN-US" style="font-size:9.5pt;font-family:Consolas"> pass</span><o:p></o:p></p>
<p class="MsoNormal" style="mso-margin-top-alt:auto;mso-margin-bottom-alt:auto"><span lang="EN-US" style="font-size:9.5pt;font-family:Consolas">
</span><o:p></o:p></p>
<p class="MsoNormal" style="mso-margin-top-alt:auto;mso-margin-bottom-alt:auto"><span lang="EN-US" style="font-size:9.5pt;font-family:Consolas">class StringDoor(Door):</span><o:p></o:p></p>
<p class="MsoNormal" style="mso-margin-top-alt:auto;mso-margin-bottom-alt:auto"><span lang="EN-US" style="font-size:9.5pt;font-family:Consolas"> def __init__(self):</span><o:p></o:p></p>
<p class="MsoNormal" style="mso-margin-top-alt:auto;mso-margin-bottom-alt:auto"><span lang="EN-US" style="font-size:9.5pt;font-family:Consolas"> self.status = "closed"</span><o:p></o:p></p>
<p class="MsoNormal" style="mso-margin-top-alt:auto;mso-margin-bottom-alt:auto"><span lang="EN-US" style="font-size:9.5pt;font-family:Consolas">
</span><o:p></o:p></p>
<p class="MsoNormal" style="mso-margin-top-alt:auto;mso-margin-bottom-alt:auto"><span lang="EN-US" style="font-size:9.5pt;font-family:Consolas"> def is_open(self):</span><o:p></o:p></p>
<p class="MsoNormal" style="mso-margin-top-alt:auto;mso-margin-bottom-alt:auto"><span lang="EN-US" style="font-size:9.5pt;font-family:Consolas"> return self.status == "open"</span><o:p></o:p></p>
<p class="MsoNormal" style="mso-margin-top-alt:auto;mso-margin-bottom-alt:auto"><span lang="EN-US" style="font-size:9.5pt;font-family:Consolas">
</span><o:p></o:p></p>
<p class="MsoNormal" style="mso-margin-top-alt:auto;mso-margin-bottom-alt:auto"><span lang="EN-US" style="font-size:9.5pt;font-family:Consolas"> def toggle(self):</span><o:p></o:p></p>
<p class="MsoNormal" style="mso-margin-top-alt:auto;mso-margin-bottom-alt:auto"><span lang="EN-US" style="font-size:9.5pt;font-family:Consolas"> if self.status == "open":</span><o:p></o:p></p>
<p class="MsoNormal" style="mso-margin-top-alt:auto;mso-margin-bottom-alt:auto"><span lang="EN-US" style="font-size:9.5pt;font-family:Consolas"> self.status = "closed"</span><o:p></o:p></p>
<p class="MsoNormal" style="mso-margin-top-alt:auto;mso-margin-bottom-alt:auto"><span lang="EN-US" style="font-size:9.5pt;font-family:Consolas"> else:</span><o:p></o:p></p>
<p class="MsoNormal" style="mso-margin-top-alt:auto;mso-margin-bottom-alt:auto"><span lang="EN-US" style="font-size:9.5pt;font-family:Consolas"> self.status = "open"</span><o:p></o:p></p>
<p class="MsoNormal" style="mso-margin-top-alt:auto;mso-margin-bottom-alt:auto"><span lang="EN-US" style="font-size:9.5pt;font-family:Consolas"> </span><o:p></o:p></p>
<p class="MsoNormal" style="mso-margin-top-alt:auto;mso-margin-bottom-alt:auto"><span lang="EN-US" style="font-size:9.5pt;font-family:Consolas">class BooleanDoor(Door):</span><o:p></o:p></p>
<p class="MsoNormal" style="mso-margin-top-alt:auto;mso-margin-bottom-alt:auto"><span lang="EN-US" style="font-size:9.5pt;font-family:Consolas"> def __init__(self):</span><o:p></o:p></p>
<p class="MsoNormal" style="mso-margin-top-alt:auto;mso-margin-bottom-alt:auto"><span lang="EN-US" style="font-size:9.5pt;font-family:Consolas"> self.status = True</span><o:p></o:p></p>
<p class="MsoNormal" style="mso-margin-top-alt:auto;mso-margin-bottom-alt:auto"><span lang="EN-US" style="font-size:9.5pt;font-family:Consolas"> </span><o:p></o:p></p>
<p class="MsoNormal" style="mso-margin-top-alt:auto;mso-margin-bottom-alt:auto"><span lang="EN-US" style="font-size:9.5pt;font-family:Consolas"> def is_open(self):</span><o:p></o:p></p>
<p class="MsoNormal" style="mso-margin-top-alt:auto;mso-margin-bottom-alt:auto"><span lang="EN-US" style="font-size:9.5pt;font-family:Consolas"> return self.status</span><o:p></o:p></p>
<p class="MsoNormal" style="mso-margin-top-alt:auto;mso-margin-bottom-alt:auto"><span lang="EN-US" style="font-size:9.5pt;font-family:Consolas">
</span><o:p></o:p></p>
<p class="MsoNormal" style="mso-margin-top-alt:auto;mso-margin-bottom-alt:auto"><span lang="EN-US" style="font-size:9.5pt;font-family:Consolas"> def toggle(self):</span><o:p></o:p></p>
<p class="MsoNormal" style="mso-margin-top-alt:auto;mso-margin-bottom-alt:auto"><span lang="EN-US" style="font-size:9.5pt;font-family:Consolas"> self.status = not (self.status)</span><o:p></o:p></p>
<p class="MsoNormal" style="mso-margin-top-alt:auto;mso-margin-bottom-alt:auto"><span lang="EN-US" style="font-size:9.5pt;font-family:Consolas"> </span><o:p></o:p></p>
<p class="MsoNormal" style="mso-margin-top-alt:auto;mso-margin-bottom-alt:auto"><span lang="EN-US" style="font-size:9.5pt;font-family:Consolas">Door.register(StringDoor)</span><o:p></o:p></p>
<p class="MsoNormal" style="mso-margin-top-alt:auto;mso-margin-bottom-alt:auto"><span lang="EN-US" style="font-size:9.5pt;font-family:Consolas">Door.register(BooleanDoor)</span><o:p></o:p></p>
<p class="MsoNormal" style="mso-margin-top-alt:auto;mso-margin-bottom-alt:auto"><span lang="EN-US">-------</span><o:p></o:p></p>
<p class="MsoNormal" style="mso-margin-top-alt:auto;mso-margin-bottom-alt:auto"><span lang="EN-US" style="font-size:9.0pt;font-family:"Courier New"">
</span><o:p></o:p></p>
<p class="MsoNormal" style="mso-margin-top-alt:auto;mso-margin-bottom-alt:auto"><span lang="EN-US">Now, all I did was to replace the abstract base class Door by a C# representation:</span><o:p></o:p></p>
<p class="MsoNormal" style="mso-margin-top-alt:auto;mso-margin-bottom-alt:auto"><span lang="EN-US" style="font-size:9.0pt;font-family:"Courier New""> </span><o:p></o:p></p>
<p class="MsoNormal" style="mso-margin-top-alt:auto;mso-margin-bottom-alt:auto"><span lang="EN-US">[File: PythonAbstractBaseClass.dll] -------</span><o:p></o:p></p>
<p class="MsoNormal" style="mso-margin-top-alt:auto;mso-margin-bottom-alt:auto;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><o:p></o:p></p>
<p class="MsoNormal" style="mso-margin-top-alt:auto;mso-margin-bottom-alt:auto;text-autospace:none">
<span lang="EN-US" style="font-size:9.5pt;font-family:Consolas;color:black;background:white">{</span><o:p></o:p></p>
<p class="MsoNormal" style="mso-margin-top-alt:auto;mso-margin-bottom-alt:auto;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><o:p></o:p></p>
<p class="MsoNormal" style="mso-margin-top-alt:auto;mso-margin-bottom-alt:auto;text-autospace:none">
<span lang="EN-US" style="font-size:9.5pt;font-family:Consolas;color:black;background:white"> {</span><o:p></o:p></p>
<p class="MsoNormal" style="mso-margin-top-alt:auto;mso-margin-bottom-alt:auto;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><o:p></o:p></p>
<p class="MsoNormal" style="mso-margin-top-alt:auto;mso-margin-bottom-alt:auto;text-autospace:none">
<span lang="EN-US" style="font-size:9.5pt;font-family:Consolas;color:black;background:white"> {</span><o:p></o:p></p>
<p class="MsoNormal" style="mso-margin-top-alt:auto;mso-margin-bottom-alt:auto;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><o:p></o:p></p>
<p class="MsoNormal" style="mso-margin-top-alt:auto;mso-margin-bottom-alt:auto;text-autospace:none">
<span lang="EN-US" style="font-size:9.5pt;font-family:Consolas;color:black;background:white"> Toggle();</span><o:p></o:p></p>
<p class="MsoNormal" style="mso-margin-top-alt:auto;mso-margin-bottom-alt:auto;text-autospace:none">
<span lang="EN-US" style="font-size:9.5pt;font-family:Consolas;color:black;background:white"> }</span><o:p></o:p></p>
<p class="MsoNormal" style="mso-margin-top-alt:auto;mso-margin-bottom-alt:auto;text-autospace:none">
<span lang="EN-US" style="font-size:9.5pt;font-family:Consolas;color:black;background:white"> </span><o:p></o:p></p>
<p class="MsoNormal" style="mso-margin-top-alt:auto;mso-margin-bottom-alt:auto;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><o:p></o:p></p>
<p class="MsoNormal" style="mso-margin-top-alt:auto;mso-margin-bottom-alt:auto;text-autospace:none">
<span lang="EN-US" style="font-size:9.5pt;font-family:Consolas;color:black;background:white"> {</span><o:p></o:p></p>
<p class="MsoNormal" style="mso-margin-top-alt:auto;mso-margin-bottom-alt:auto;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><o:p></o:p></p>
<p class="MsoNormal" style="mso-margin-top-alt:auto;mso-margin-bottom-alt:auto;text-autospace:none">
<span lang="EN-US" style="font-size:9.5pt;font-family:Consolas;color:black;background:white"> Toggle();</span><o:p></o:p></p>
<p class="MsoNormal" style="mso-margin-top-alt:auto;mso-margin-bottom-alt:auto;text-autospace:none">
<span lang="EN-US" style="font-size:9.5pt;font-family:Consolas;color:black;background:white"> }</span><o:p></o:p></p>
<p class="MsoNormal" style="mso-margin-top-alt:auto;mso-margin-bottom-alt:auto;text-autospace:none">
<span lang="EN-US" style="font-size:9.5pt;font-family:Consolas;color:black;background:white"> </span><o:p></o:p></p>
<p class="MsoNormal" style="mso-margin-top-alt:auto;mso-margin-bottom-alt:auto;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><o:p></o:p></p>
<p class="MsoNormal" style="mso-margin-top-alt:auto;mso-margin-bottom-alt:auto;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><o:p></o:p></p>
<p class="MsoNormal" style="mso-margin-top-alt:auto;mso-margin-bottom-alt:auto;text-autospace:none">
<span style="font-size:9.5pt;font-family:Consolas;color:black;background:white"> }</span><o:p></o:p></p>
<p class="MsoNormal" style="mso-margin-top-alt:auto;mso-margin-bottom-alt:auto;text-autospace:none">
<span style="font-size:9.5pt;font-family:Consolas;color:black;background:white">}</span><o:p></o:p></p>
<p class="MsoNormal" style="mso-margin-top-alt:auto;mso-margin-bottom-alt:auto"><span lang="EN-US">-------</span><o:p></o:p></p>
<p class="MsoNormal" style="mso-margin-top-alt:auto;mso-margin-bottom-alt:auto"><span lang="EN-US" style="font-size:9.0pt;font-family:"Courier New""> </span><o:p></o:p></p>
<p class="MsoNormal" style="mso-margin-top-alt:auto;mso-margin-bottom-alt:auto"><span lang="EN-US">Removing Door from the Python part and importing it from the .NET assembly instead, I end up with this:</span><o:p></o:p></p>
<p class="MsoNormal" style="mso-margin-top-alt:auto;mso-margin-bottom-alt:auto"><span lang="EN-US" style="font-size:9.0pt;font-family:"Courier New""> </span><o:p></o:p></p>
<p class="MsoNormal" style="mso-margin-top-alt:auto;mso-margin-bottom-alt:auto"><span lang="EN-US">[File: room2.py] -------</span><o:p></o:p></p>
<p class="MsoNormal" style="mso-margin-top-alt:auto;mso-margin-bottom-alt:auto"><span lang="EN-US" style="font-size:9.0pt;font-family:"Courier New"">import clr</span><o:p></o:p></p>
<p class="MsoNormal" style="mso-margin-top-alt:auto;mso-margin-bottom-alt:auto"><span lang="EN-US" style="font-size:9.0pt;font-family:"Courier New"">import abc</span><o:p></o:p></p>
<p class="MsoNormal" style="mso-margin-top-alt:auto;mso-margin-bottom-alt:auto"><span lang="EN-US" style="font-size:9.0pt;font-family:"Courier New"">from PythonAbstractBaseClass import Door</span><o:p></o:p></p>
<p class="MsoNormal" style="mso-margin-top-alt:auto;mso-margin-bottom-alt:auto"><span lang="EN-US" style="font-size:9.0pt;font-family:"Courier New""> </span><o:p></o:p></p>
<p class="MsoNormal" style="mso-margin-top-alt:auto;mso-margin-bottom-alt:auto"><span lang="EN-US" style="font-size:9.0pt;font-family:"Courier New"">class Room(object):</span><o:p></o:p></p>
<p class="MsoNormal" style="mso-margin-top-alt:auto;mso-margin-bottom-alt:auto"><span lang="EN-US" style="font-size:9.0pt;font-family:"Courier New""> def __init__(self, door):</span><o:p></o:p></p>
<p class="MsoNormal" style="mso-margin-top-alt:auto;mso-margin-bottom-alt:auto"><span lang="EN-US" style="font-size:9.0pt;font-family:"Courier New""> self.door = door</span><o:p></o:p></p>
<p class="MsoNormal" style="mso-margin-top-alt:auto;mso-margin-bottom-alt:auto"><span lang="EN-US" style="font-size:9.0pt;font-family:"Courier New""> </span><o:p></o:p></p>
<p class="MsoNormal" style="mso-margin-top-alt:auto;mso-margin-bottom-alt:auto"><span lang="EN-US" style="font-size:9.0pt;font-family:"Courier New""> def open(self):</span><o:p></o:p></p>
<p class="MsoNormal" style="mso-margin-top-alt:auto;mso-margin-bottom-alt:auto"><span lang="EN-US" style="font-size:9.0pt;font-family:"Courier New""> self.door.open()</span><o:p></o:p></p>
<p class="MsoNormal" style="mso-margin-top-alt:auto;mso-margin-bottom-alt:auto"><span lang="EN-US" style="font-size:9.0pt;font-family:"Courier New""> </span><o:p></o:p></p>
<p class="MsoNormal" style="mso-margin-top-alt:auto;mso-margin-bottom-alt:auto"><span lang="EN-US" style="font-size:9.0pt;font-family:"Courier New""> def close(self):</span><o:p></o:p></p>
<p class="MsoNormal" style="mso-margin-top-alt:auto;mso-margin-bottom-alt:auto"><span lang="EN-US" style="font-size:9.0pt;font-family:"Courier New""> self.door.close()</span><o:p></o:p></p>
<p class="MsoNormal" style="mso-margin-top-alt:auto;mso-margin-bottom-alt:auto"><span lang="EN-US" style="font-size:9.0pt;font-family:"Courier New""> </span><o:p></o:p></p>
<p class="MsoNormal" style="mso-margin-top-alt:auto;mso-margin-bottom-alt:auto"><span lang="EN-US" style="font-size:9.0pt;font-family:"Courier New""> def is_open(self):</span><o:p></o:p></p>
<p class="MsoNormal" style="mso-margin-top-alt:auto;mso-margin-bottom-alt:auto"><span lang="EN-US" style="font-size:9.0pt;font-family:"Courier New""> return self.door.is_open()</span><o:p></o:p></p>
<p class="MsoNormal" style="mso-margin-top-alt:auto;mso-margin-bottom-alt:auto"><span lang="EN-US" style="font-size:9.0pt;font-family:"Courier New"">
</span><o:p></o:p></p>
<p class="MsoNormal" style="mso-margin-top-alt:auto;mso-margin-bottom-alt:auto"><span lang="EN-US" style="font-size:9.0pt;font-family:"Courier New"">class StringDoor(Door):</span><o:p></o:p></p>
<p class="MsoNormal" style="mso-margin-top-alt:auto;mso-margin-bottom-alt:auto"><span lang="EN-US" style="font-size:9.0pt;font-family:"Courier New""> def __init__(self):</span><o:p></o:p></p>
<p class="MsoNormal" style="mso-margin-top-alt:auto;mso-margin-bottom-alt:auto"><span lang="EN-US" style="font-size:9.0pt;font-family:"Courier New""> self.status = "closed"</span><o:p></o:p></p>
<p class="MsoNormal" style="mso-margin-top-alt:auto;mso-margin-bottom-alt:auto"><span lang="EN-US" style="font-size:9.0pt;font-family:"Courier New"">
</span><o:p></o:p></p>
<p class="MsoNormal" style="mso-margin-top-alt:auto;mso-margin-bottom-alt:auto"><span lang="EN-US" style="font-size:9.0pt;font-family:"Courier New""> def is_open(self):</span><o:p></o:p></p>
<p class="MsoNormal" style="mso-margin-top-alt:auto;mso-margin-bottom-alt:auto"><span lang="EN-US" style="font-size:9.0pt;font-family:"Courier New""> return self.status == "open"</span><o:p></o:p></p>
<p class="MsoNormal" style="mso-margin-top-alt:auto;mso-margin-bottom-alt:auto"><span lang="EN-US" style="font-size:9.0pt;font-family:"Courier New"">
</span><o:p></o:p></p>
<p class="MsoNormal" style="mso-margin-top-alt:auto;mso-margin-bottom-alt:auto"><span lang="EN-US" style="font-size:9.0pt;font-family:"Courier New""> def toggle(self):</span><o:p></o:p></p>
<p class="MsoNormal" style="mso-margin-top-alt:auto;mso-margin-bottom-alt:auto"><span lang="EN-US" style="font-size:9.0pt;font-family:"Courier New""> if self.status == "open":</span><o:p></o:p></p>
<p class="MsoNormal" style="mso-margin-top-alt:auto;mso-margin-bottom-alt:auto"><span lang="EN-US" style="font-size:9.0pt;font-family:"Courier New""> self.status = "closed"</span><o:p></o:p></p>
<p class="MsoNormal" style="mso-margin-top-alt:auto;mso-margin-bottom-alt:auto"><span lang="EN-US" style="font-size:9.0pt;font-family:"Courier New""> else:</span><o:p></o:p></p>
<p class="MsoNormal" style="mso-margin-top-alt:auto;mso-margin-bottom-alt:auto"><span lang="EN-US" style="font-size:9.0pt;font-family:"Courier New""> self.status = "open"</span><o:p></o:p></p>
<p class="MsoNormal" style="mso-margin-top-alt:auto;mso-margin-bottom-alt:auto"><span lang="EN-US" style="font-size:9.0pt;font-family:"Courier New""> </span><o:p></o:p></p>
<p class="MsoNormal" style="mso-margin-top-alt:auto;mso-margin-bottom-alt:auto"><span lang="EN-US" style="font-size:9.0pt;font-family:"Courier New"">class BooleanDoor(Door):</span><o:p></o:p></p>
<p class="MsoNormal" style="mso-margin-top-alt:auto;mso-margin-bottom-alt:auto"><span lang="EN-US" style="font-size:9.0pt;font-family:"Courier New""> def __init__(self):</span><o:p></o:p></p>
<p class="MsoNormal" style="mso-margin-top-alt:auto;mso-margin-bottom-alt:auto"><span lang="EN-US" style="font-size:9.0pt;font-family:"Courier New""> self.status = True</span><o:p></o:p></p>
<p class="MsoNormal" style="mso-margin-top-alt:auto;mso-margin-bottom-alt:auto"><span lang="EN-US" style="font-size:9.0pt;font-family:"Courier New""> </span><o:p></o:p></p>
<p class="MsoNormal" style="mso-margin-top-alt:auto;mso-margin-bottom-alt:auto"><span lang="EN-US" style="font-size:9.0pt;font-family:"Courier New""> def is_open(self):</span><o:p></o:p></p>
<p class="MsoNormal" style="mso-margin-top-alt:auto;mso-margin-bottom-alt:auto"><span lang="EN-US" style="font-size:9.0pt;font-family:"Courier New""> return self.status</span><o:p></o:p></p>
<p class="MsoNormal" style="mso-margin-top-alt:auto;mso-margin-bottom-alt:auto"><span lang="EN-US" style="font-size:9.0pt;font-family:"Courier New"">
</span><o:p></o:p></p>
<p class="MsoNormal" style="mso-margin-top-alt:auto;mso-margin-bottom-alt:auto"><span lang="EN-US" style="font-size:9.0pt;font-family:"Courier New""> def toggle(self):</span><o:p></o:p></p>
<p class="MsoNormal" style="mso-margin-top-alt:auto;mso-margin-bottom-alt:auto"><span lang="EN-US" style="font-size:9.0pt;font-family:"Courier New""> self.status = not (self.status)</span><o:p></o:p></p>
<p class="MsoNormal" style="mso-margin-top-alt:auto;mso-margin-bottom-alt:auto"><span lang="EN-US" style="font-size:9.0pt;font-family:"Courier New""> </span><o:p></o:p></p>
<p class="MsoNormal" style="mso-margin-top-alt:auto;mso-margin-bottom-alt:auto"><span lang="EN-US" style="font-size:9.0pt;font-family:"Courier New"">Door.register(StringDoor)</span><o:p></o:p></p>
<p class="MsoNormal" style="mso-margin-top-alt:auto;mso-margin-bottom-alt:auto"><span lang="EN-US" style="font-size:9.0pt;font-family:"Courier New"">Door.register(BooleanDoor)</span><o:p></o:p></p>
<p class="MsoNormal" style="mso-margin-top-alt:auto;mso-margin-bottom-alt:auto"><span lang="EN-US">-------</span><o:p></o:p></p>
<p class="MsoNormal" style="mso-margin-top-alt:auto;mso-margin-bottom-alt:auto"><span lang="EN-US" style="font-size:9.0pt;font-family:"Courier New"">
</span><o:p></o:p></p>
<p class="MsoNormal" style="mso-margin-top-alt:auto;mso-margin-bottom-alt:auto"><span lang="EN-US">But this fails with the following error message:</span><o:p></o:p></p>
<p class="MsoNormal" style="mso-margin-top-alt:auto;mso-margin-bottom-alt:auto"><span lang="EN-US" style="font-size:9.0pt;font-family:"Courier New""> </span><o:p></o:p></p>
<p class="MsoNormal" style="mso-margin-top-alt:auto;mso-margin-bottom-alt:auto"><span lang="EN-US" style="font-size:9.0pt;font-family:"Courier New""> Door.register(StringDoor)</span><o:p></o:p></p>
<p class="MsoNormal" style="mso-margin-top-alt:auto;mso-margin-bottom-alt:auto"><span lang="EN-US" style="font-size:9.0pt;font-family:"Courier New"">AttributeError: type object 'Door' has no attribute 'register'</span><o:p></o:p></p>
<p class="MsoNormal" style="mso-margin-top-alt:auto;mso-margin-bottom-alt:auto"><span lang="EN-US" style="font-size:9.0pt;font-family:"Courier New""> </span><o:p></o:p></p>
<p class="MsoNormal" style="mso-margin-top-alt:auto;mso-margin-bottom-alt:auto"><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><o:p></o:p></p>
<p class="MsoNormal" style="mso-margin-top-alt:auto;mso-margin-bottom-alt:auto"><span lang="EN-US"> </span><o:p></o:p></p>
<p class="MsoNormal" style="mso-margin-top-alt:auto;mso-margin-bottom-alt:auto"><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><o:p></o:p></p>
<p class="MsoNormal" style="mso-margin-top-alt:auto;mso-margin-bottom-alt:auto"><span lang="EN-US"> </span><o:p></o:p></p>
<p class="MsoNormal" style="mso-margin-top-alt:auto;mso-margin-bottom-alt:auto"><span lang="EN-US" style="font-size:9.0pt;font-family:"Courier New""> sdoor = StringDoor()</span><o:p></o:p></p>
<p class="MsoNormal" style="mso-margin-top-alt:auto;mso-margin-bottom-alt:auto"><span lang="EN-US" style="font-size:9.0pt;font-family:"Courier New"">TypeError: cannot instantiate abstract class</span><o:p></o:p></p>
<p class="MsoNormal" style="mso-margin-top-alt:auto;mso-margin-bottom-alt:auto"><span lang="EN-US" style="font-size:9.0pt;font-family:"Courier New""> </span><o:p></o:p></p>
<p class="MsoNormal" style="mso-margin-top-alt:auto;mso-margin-bottom-alt:auto"><span lang="EN-US">Is there a way to inherit from an abstract .NET class or is this is missing feature?</span><o:p></o:p></p>
<p class="MsoNormal" style="mso-margin-top-alt:auto;mso-margin-bottom-alt:auto"><span lang="EN-US"> </span><o:p></o:p></p>
<p class="MsoNormal" style="mso-margin-top-alt:auto;mso-margin-bottom-alt:auto"><span lang="EN-US">Thanks in advance,</span><o:p></o:p></p>
<p class="MsoNormal" style="mso-margin-top-alt:auto;mso-margin-bottom-alt:auto"><span lang="EN-US" style="color:#888888"> </span><span style="color:#888888"><o:p></o:p></span></p>
<p class="MsoNormal" style="mso-margin-top-alt:auto;mso-margin-bottom-alt:auto"><span lang="EN-US" style="color:#888888">Henning</span><span style="color:#888888"><o:p></o:p></span></p>
<p class="MsoNormal" style="mso-margin-top-alt:auto;mso-margin-bottom-alt:auto"><span lang="EN-US" style="color:#888888"> </span><span style="color:#888888"><o:p></o:p></span></p>
</div>
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<p class="MsoNormal"><br>
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<p class="MsoNormal"><o:p> </o:p></p>
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