DependencyProperty doesn't fire ValueChanged when new value is the same
You can wrap your value up in an object, i.e. create a class to hold it - then set the property to a new instance of that class containing the new value, every time. That means you're creating ~10 objects per second, but they are each different, will trigger the change event, and are only small (will be GC'd anyway). :)
Another alternative is to switch the value temporarily to something else then restore the previous one. You can do this entire trick transparently in the Coerce callback as such:
public static readonly DependencyProperty TestProperty = DependencyProperty.Register( "Test", typeof(object), typeof(School), new PropertyMetadata(null, TestChangedCallback, TestCoerceCallback));static object TestCoerceCallback(DependencyObject d, object baseValue){ if (baseValue != null && (d.GetValue(TestProperty) == baseValue)) { d.SetCurrentValue(TestProperty, null); d.SetCurrentValue(TestProperty, baseValue); } return baseValue;}Just make sure your property code can handle the null value case gracefully.