private void delete_all_button_Click(object sender, EventArgs e) { DialogResult userChoice = MessageBox.Show(@"Delete all entries?", @"Warning", MessageBoxButtons.YesNo, MessageBoxIcon.Warning); if (userChoice == DialogResult.Yes) { _deletedAll = true; _deletedBuses.AddRange(_busService.GetAllBusSchedules()); _busService.DeleteAllBuses(); bus_schedules_listview.Items.Clear(); } }