public MainWindow() { InitializeComponent(); dataConnection = new DataConnection(); dataConnection.AddInsertValidator(new RoomInsertValidator()); dataConnection.AddInsertValidator(new CustomerInsertVlidator()); dataConnection.AddInsertValidator(new ReservationInsertValidator()); reservationsList = new ReservationsList(ReservationListView, ReservationInfoPanel, dataConnection); dataConnection.OnDBChange += (dbContext, type) => { if (type == typeof(Customers) || type == typeof(Rooms)) { RoomCustomerCountText.Content = RoomCustomerCountTextUpdate; } }; RoomCustomerCountText.Content = RoomCustomerCountTextUpdate; }