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POObservableCollection dependency property does not update when item in collection is deleted
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copied!<p>I have a attached property of type ObservableCollection on a control. If I add or remove items from the collection, the ui does not update. However if I replace the collection within with a new one the ViewModel the ui does update.</p> <p>Can someone give me an example of what I need to do within the Dependency object so that it can handle changes within the collection?</p> <p>Part of the dependency object is listed below:</p> <pre><code>public class RadCalendarBehavior : DependencyObject { private static void OnSpecialDaysChanged(DependencyObject d, DependencyPropertyChangedEventArgs e) { var calendar = d as RadCalendar; if (e.NewValue != null) { calendar.DayTemplateSelector = new SpecialDaySelector((ObservableCollection<DateTime>)e.NewValue, GetSpecialDayTemplate(d)); } } public static ObservableCollection<DateTime> GetSpecialDays(DependencyObject obj) { return (ObservableCollection<DateTime>)obj.GetValue(SpecialDaysProperty); } public static void SetSpecialDays(DependencyObject obj, ObservableCollection<DateTime> value) { obj.SetValue(SpecialDaysProperty, value); } public static readonly DependencyProperty SpecialDaysProperty = DependencyProperty.RegisterAttached("SpecialDays", typeof(ObservableCollection<DateTime>), typeof(RadCalendarBehavior), new UIPropertyMetadata(null, OnSpecialDaysChanged)); } } </code></pre> <p>I understand that I need to register that the collection has changed, but I am unsure how to do this within the dependency property</p>

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