Re: [Python.NET] How to handle INotifyPropertyChanged interface

It seems inheriting from INotifyPropertyChanged is the cause
self.window = System.Windows.Markup.XamlReader.Load(outStream)self.window.DataContext = MyViewModel()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")  
The above code works fine. 
but if switch inheritance to class MyViewModel(System.ComponentModel.INotifyPropertyChanged):and nothing else changed, python gives 
"The process terminates due to StackOverflowException"
Not sure why. 

Thanks for the help
From: [email protected]
To: [email protected]
Subject: How to handle INotifyPropertyChanged interface
Date: Thu, 31 Mar 2016 20:38:38 -0400




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 .Netclass 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.

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