I have an ObservableCollection of items of my class "PlaylistItem" that implements INotifyPropertyChanged. The collection is databound to a ListBox and everything else is working. I want to know what markup to use to trigger a style change of the wrapping ListBoxItem based on a property (e.g. "Playing", bool) of the PlaylistItem. How to I use FindAncestor to trigger the change? I can to this in code, but I know I that I can (somehow) do it in markup. Thanks in advance.