DependencyProperty of type IList - collection change

I do not know how much it will help you, but because in most cases, the ObservableCollection<T> acts as a data source, we can use this, so we do the following:

1) In the user control create DP .

 public static readonly DependencyProperty ItemsSourceProperty = DependencyProperty.Register("ItemsSource", typeof(IEnumerable<object>), typeof(MyUserControl), new PropertyMetadatadefault(IEnumerable<object>))); public IEnumerable<object> ItemsSource { get { return (IEnumerable<object>)GetValue(ItemsSourceProperty); } set { SetValue(ItemsSourceProperty, value); } } 

2) In the controller constructor, we subscribe to change the value of your DP .

 public MyUserControl() { InitializeComponent(); var dp = DependencyPropertyDescriptor.FromProperty(ItemsSourceProperty, typeof(MyUserControl)); dp?.AddValueChanged(this, Handler); } 

3) In the handler for a DP change, we INotifyCollectionChanged your property to INotifyCollectionChanged and subscribe to collection change notifications.

 private void Handler(object sender, EventArgs eventArgs) { var nc = ItemsSource as INotifyCollectionChanged; if (nc != null) nc.CollectionChanged += OnCollectionChanged; } 

4) Next, we implement your logic that reacts to changes in the collection:

 private void OnCollectionChanged(object sender, NotifyCollectionChangedEventArgs e) { // Ваша логика на реакцию об изменении свойства } 

All entirely:

 public partial class MyUserControl : UserControl { public MyUserControl() { InitializeComponent(); var dp = DependencyPropertyDescriptor.FromProperty(ItemsSourceProperty, typeof(MyUserControl)); dp?.AddValueChanged(this, Handler); } private void Handler(object sender, EventArgs eventArgs) { var nc = ItemsSource as INotifyCollectionChanged; if (nc != null) nc.CollectionChanged += OnCollectionChanged; } private void OnCollectionChanged(object sender, NotifyCollectionChangedEventArgs e) { // Ваш код } public static readonly DependencyProperty ItemsSourceProperty = DependencyProperty.Register( "ItemsSource", typeof(IEnumerable<object>), typeof(MyUserControl), new PropertyMetadata(default(IEnumerable<object>))); public IEnumerable<object> ItemsSource { get { return (IEnumerable<object>)GetValue(ItemsSourceProperty); } set { SetValue(ItemsSourceProperty, value); } } }