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Python grandchild of .NET class is not created correctly if "__namespace__" attribute is set #544

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testrunner123 opened this issue Sep 15, 2017 · 2 comments
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Python grandchild of .NET class is not created correctly if "__namespace__" attribute is set #544

testrunner123 opened this issue Sep 15, 2017 · 2 comments

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@testrunner123
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testrunner123 commented Sep 15, 2017 •
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Environment

Details

  • Describe what you were trying to get done.

I am trying to use python child of .NET class in python grandchild.

class A:
  def __init__(self):
      self.foo()
  def foo(self): print('A.foo')

class B(A):
  def foo(self): print('B.foo')

a = A()
b = B()

works like expected and prints:

A.foo
B.foo

Consider Python classes constructed with pythonnet:

import clr
import System.Windows.Forms as WinForms

class PythonGroupBox(WinForms.GroupBox):
    def __init__(self):
        print("PythonGroupBox.__init__")
        self.MyInit()

    def MyInit(self):
        print("PythonGroupBox MyInit")

class PythonGroupBoxDerived(PythonGroupBox):
    def MyInit(self):
        print("PythonGroupBoxDerived MyInit")

grp1 = PythonGroupBox()
grp2 = PythonGroupBoxDerived()

works fine and prints:

PythonGroupBox.init
PythonGroupBox MyInit
PPythonGroupBox.init
PythonGroupBoxDerived MyInit

Now the same with "namespace":

import clr
import System.Windows.Forms as WinForms

class PythonGroupBox(WinForms.GroupBox):
    __namespace__ = "System.Windows.Forms"
    def __init__(self):
        print("PythonGroupBox.__init__")
        self.MyInit()

    def MyInit(self):
        print("PythonGroupBox MyInit")

class PythonGroupBoxDerived(PythonGroupBox):
    def MyInit(self):
        print("PythonGroupBoxDerived MyInit")

grp1 = PythonGroupBox()
grp2 = PythonGroupBoxDerived()

The output is:

PythonGroupBox.init
PythonGroupBox MyInit
PythonGroupBox.init
PythonGroupBox MyInit

Error (1), because MyInit Method didn't get overloaded !!!

One more try:

import clr
import System.Windows.Forms as WinForms

class PythonGroupBox(WinForms.GroupBox):
    __namespace__ = "System.Windows.Forms"
    def __init__(self):
        print("PythonGroupBox.__init__")
        self.MyInit()

    def MyInit(self):
        print("PythonGroupBox MyInit")

class PythonGroupBoxDerived(PythonGroupBox):
    __namespace__ = "System.Windows.Forms"
    def MyInit(self):
        print("PythonGroupBoxDerived MyInit")

grp1 = PythonGroupBox()
grp2 = PythonGroupBoxDerived()

Output gets really weird:

PythonGroupBox.init
PythonGroupBox MyInit

Error (2): during construction of PythonGroupBoxDerived the init() method was not called at all !!!

Important: this issue has nothing to do with issue #503: if I undo that fix than constructors get called twice, but errors described here persist.
@testrunner123 testrunner123 changed the title Python granchild of .NET class is not created correctly if "__namespace__" attribute is set Python grandchild of .NET class is not created correctly if "__namespace__" attribute is set Sep 15, 2017
@testrunner123
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I have made a unit test for this on a branch. Does some one knows how it is designed to work?

@lostmsu
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lostmsu commented Sep 17, 2022

This works as expected:

import System.Windows.Forms as WinForms

class PythonGroupBox(WinForms.GroupBox):
    __namespace__ = "System.Windows.Forms"
    def __init__(self):
        super().__init__()
        print("PythonGroupBox.__init__")
        self.MyInit()
    def MyInit(self):
        print("PythonGroupBox MyInit")

class PythonGroupBoxDerived(PythonGroupBox):
    __namespace__ = "System.Windows.Forms"
    def __init__(self):
        super().__init__()
    def MyInit(self):
        print("PythonGroupBoxDerived MyInit")

grp1 = PythonGroupBox()
grp2 = PythonGroupBoxDerived()

/ grp1 = PythonGroupBox()
PythonGroupBox.init
PythonGroupBox MyInit
/ grp2 = PythonGroupBoxDerived()
PythonGroupBox.init
PythonGroupBoxDerived MyInit

However, without explicitly redeclared __init__ in the PythonGroupBoxDerived base constructor is not called, for which I opened a separate issue: #1945

@lostmsu lostmsu closed this as completed Sep 17, 2022
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@lostmsu @testrunner123