This method is definitely missing here: DependencyPropertyDescriptor .FromProperty(RadioButton.IsCheckedProperty, typeof(RadioButton)) .AddValueChanged(radioButton, (s,e) => { /* … */ }); Caution: Because DependencyPropertyDescriptor has a static list of all handlers in application every object referenced in those handlers will leak if the handler is not eventually removed. (It does not work like common events on instance objects.) Always … Read more
I would suggest not to use ObservableCollection as the type of an Items dependency property. The reason for having an ObservableCollection here (I guess) is to enable the UserControl to attach a CollectionChanged handler when the property value is assigned. But ObservableCollection is too specific. The approach in WPF (e.g. in ItemsControl.ItemsSource) is to define … Read more
The setter of your dependency property will not be called when the property is set in XAML. WPF will instead call the SetValue method directly. See MSDN XAML Loading and Dependency Properties for an explanation why the setter is not called. You would have to register a PropertyChangedCallback with property metadata.
The dependency property declaration must look like this: public static readonly DependencyProperty TestProperty = DependencyProperty.Register( nameof(Test), typeof(string), typeof(MyControl), new PropertyMetadata(“DEFAULT”)); public string Test { get { return (string)GetValue(TestProperty); } set { SetValue(TestProperty, value); } } The binding in the UserControl’s XAML must set the control instance as the source object, e.g. by setting the Bindings’s … Read more
You would have to register a PropertyChangedCallback with property metadata. The reason is that dependency properties set in XAML or by bindings or some other source do not invoke the CLR wrapper (the setter method). The reason is explained in the XAML Loading and Dependency Properties article on MSDN: For implementation reasons, it is computationally … Read more
Kent wrote an interesting blog about this topic: View Models: POCOs versus DependencyObjects. Short summary: DependencyObjects are not marked as serializable The DependencyObject class overrides and seals the Equals() and GetHashCode() methods A DependencyObject has thread affinity – it can only be accessed on the thread on which it was created I prefer the POCO … Read more