Hi, I have an observable collection implemented in my user control which indicates states of a device. Based on the collection change, the user control is to trigger animations(subscribe to collectionchanged event). The observable collection is implemented as a dependency property. In the application, I data bind the device states to the user control observableCollection using one-way databinding. When a new state is added in the application, I can see the ObservableCollection in the user control is updated. However, the CollectionChanged event never got fired, so no animations. Does anyone has an idea why this is so? Thank you in advance.