private void btnDrivers_Click(object sender, RoutedEventArgs e)
        {
            var driverRepository = new SqlDriverRepository(_connectionString);
            var driverWindow     = new DriverWindow(_customer, driverRepository.SelectAll());

            wndMainWindow.IsEnabled = false;
            driverWindow.ShowDialog();
            wndMainWindow.IsEnabled = true;
        }
        private void btnDriver_Click(object sender, RoutedEventArgs e)
        {
            var driverRepository = new SqlDriverRepository(_connectionString);

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

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

            var driverWindow = new DriverWindow(_customer, driverRepository.GetDriversBySchedule(scheduleId));

            wndSchedule.Close();
            driverWindow.ShowDialog();
        }