NotifyCollectionsActions

        class NotifyCollectionsActions
        {
            public readonly INotifyCollectionChanged[] Collections;
            public readonly Action ChangedAction;

            public NotifyCollectionsActions(Action changedAction, params INotifyCollectionChanged[] collections)
            {
                this.Collections = collections;
                this.ChangedAction = changedAction;

                foreach (INotifyCollectionChanged collection in Collections)
                {
                    collection.CollectionChanged += (s, e) =>
                    {
                        if (ChangedAction != null)
                            ChangedAction();
                    };
                }
            }
        }