public virtual void Dispose()
{
if (ObservedInstance != null)
{
ObservedInstance.PropertyChanged -= HandleNextPropertyChanged;
}
if (NextEntry != null)
{
NextEntry.Dispose();
}
}
private void HandleNextPropertyChanged(object sender, PropertyChangedEventArgs args)
{
if (args.PropertyName != ObservedProperty.Name)
{
return;
}
var newValue = ObservedProperty.GetValue(ObservedInstance);
if (newValue != null && !(newValue is INotifyPropertyChanged))
{
throw new InvalidOperationException();
}
NextEntry.Reattach(newValue as INotifyPropertyChanged);
}
protected virtual void Reattach(INotifyPropertyChanged observedInstance)
{
ObservedInstance = observedInstance;
if (observedInstance == null || NextEntry == null)
{
return;
}
var nextInstance = ObservedProperty.GetValue(ObservedInstance);
if (nextInstance != null && !(nextInstance is INotifyPropertyChanged))
{
throw new InvalidOperationException();
}
NextEntry.Reattach(nextInstance as INotifyPropertyChanged);
}
