ObservableCollectionExtensions static class ObservableCollectionExtensions Performance helpers avoiding struct enumerator building and generally faster accessing. Documentation Code public static bool Any<T>(this ObservableCollection<T> collection) public static bool Any<T>(this ObservableCollection<T> collection, Func<T, bool> predicate) public static int Count<T>(this ObservableCollection<T> collection, Func<T, bool> predicate) public static T ElementAt<T>(this ObservableCollection<T> collection, int index) public static T First<T>(this ObservableCollection<T> collection) public static T First<T>(this ObservableCollection<T> collection, Func<T, bool> predicate) public static T FirstOrDefault<T>(this ObservableCollection<T> collection, Func<T, bool> predicate) public static T FirstOrDefault<T>(this ObservableCollection<T> collection)