I am still trying to figure out how to implement WPF MVVM with Python.Net.

Previously, I have successfully used System.Dynamic.ExpandoObject as a ViewModel container 

self.window = System.Windows.Markup.XamlReader.Load(outStream)

self.window.DataContext = DotNetExpandoObject()

where DotNetExpandoObject is a wrapper class for System.Dynamic.ExpandoObject 

class DotNetExpandoObject(System.Dynamic.ExpandoObject):

...  in which I redefined __getattr__ and __setattr__ 

it works flawlessly as System.Dynamic.ExpandoObject implements INotifyPropertyChange interface already

Now, I would like to get away from using System.Dynamic.ExpandoObject but to implement my own

I first tried to expose a python class back to .Net

class MyViewModel(System.Object):

    __namespace__ = "WPFPyDemo"

    def __init__(self):

        super(MyViewModel,self).__init__()

        self._inputText = "Line - in"

    @clr.clrproperty(str)

    def inputText(self):

        return self._inputText

    @inputText.setter

    def inputText(self,value):

        self._inputText = value

        self.OnPropertyChanged("inputText")  

self.window.DataContext = MyViewModel()

The one direction data binding works fine, and the "Line - in" text correctly shows up in the textblock control.

obviously this is not sufficient as there is no INotifyPropertyChange interface. 

So, I inherit the interface , and tries to implement the typical C# code

" public event PropertyChangedEventHandler PropertyChanged"  

-- not sure how to handle event in Python.Net, the follow code probably is completely wrong

class ViewModel(System.ComponentModel.INotifyPropertyChanged):

    __namespace__ = "WPFPy"

    def __init__(self):

        super(ViewModel, self).__init__()

        self.PropertyChanged = System.ComponentModel.PropertyChangedEventHandler

    def OnPropertyChanged(self, propertyName):

        if self.PropertyChanged != None:

            PropertyChanged(self, System.ComponentModel.PropertyChangedEventArgs(propertyName))

class MyViewModel(ViewModel):

    __namespace__ = "WPFPyDemo"

    def __init__(self):

        super(MyViewModel,self).__init__()

        self._inputText = "Line - in"

    @clr.clrproperty(str)

    def inputText(self):

        return self._inputText

    @inputText.setter

    def inputText(self,value):

        self._inputText = value

        self.OnPropertyChanged("inputText")  

The process terminates due to StackOverflowException. 

Looks like the error happens when WFP recoganized INotifyPropertyChange interface and tries to access MyViewModel class via it.