private void BatchNumber_SelectionChanged(object sender, SelectionChangedEventArgs e) { cbb_DayNumber.Items.Clear(); cbb_DayNumber.SelectedIndex = -1; int chosenBatchNr = int.Parse(cbb_BatchNumber.SelectedItem.ToString()); List <int> days = batchRepo.GetDayNrByBatchNr(chosenBatchNr); foreach (int day in days) { cbb_DayNumber.Items.Add(day); } }