public static void SubscribeWeak([CanBeNull] this INotifyPropertyChanged obj, [CanBeNull] FrameworkElement parent,
[CanBeNull] EventHandler <PropertyChangedEventArgs> onPropertyChanged)
{
if (parent == null || obj == null || onPropertyChanged == null)
{
return;
}
obj.SubscribeWeak(onPropertyChanged);
parent.OnActualUnload(() => {
obj.UnsubscribeWeak(onPropertyChanged);
});
}
