private void btnTimetable_Click(object sender, RoutedEventArgs e)
        {
            var scheduleRepository = new SqlScheduleRepository(_connectionString);
            var timeTableWindow    = new ScheduleWindow(_customer, scheduleRepository.SelectAll());

            wndMainWindow.IsEnabled = false;
            timeTableWindow.ShowDialog();
            wndMainWindow.IsEnabled = true;
        }
        private void btnAdd_Click(object sender, RoutedEventArgs e)
        {
            var addScheduleWindow = new AddScheduleWindow();

            wndSchedule.IsEnabled = false;
            addScheduleWindow.ShowDialog();

            var scheduleRepository = new SqlScheduleRepository(_connectionString);

            dgrDataSchedule.ItemsSource = scheduleRepository.SelectAll();

            wndSchedule.IsEnabled = true;
        }
        private void btnDelete_Click(object sender, RoutedEventArgs e)
        {
            var scheduleRepository = new SqlScheduleRepository(_connectionString);

            if (dgrDataSchedule.SelectedItem == null)
            {
                MessageBox.Show("Not selected schedule.", "Selection", MessageBoxButton.OK, MessageBoxImage.Error);
                return;
            }

            int scheduleId = ((TimeTable)dgrDataSchedule.SelectedItem).Id;

            MessageBoxResult answer = MessageBox.Show(String.Format("You really want to delete bus #{0}?",
                                                                    ((TimeTable)dgrDataSchedule.SelectedItem).Id), "Deleting", MessageBoxButton.YesNo, MessageBoxImage.Question);

            if (answer == MessageBoxResult.Yes)
            {
                scheduleRepository.Delete(scheduleId);
                dgrDataSchedule.ItemsSource = scheduleRepository.SelectAll();
            }
        }