private void RemoveBtn_Click(object sender, EventArgs e) { KoszykList.Rows.Clear(); try { if (KoszykSelectedVehicle == null) { throw new NullReferenceException("No vehicle was selected"); } var vehicle = BookedVehicles.Where(n => n.Model == KoszykSelectedVehicle.Model && n.Mark == KoszykSelectedVehicle.Mark && n.Price == KoszykSelectedVehicle.Price && n.ProductionYear == KoszykSelectedVehicle.ProductionYear && n.SalonName == KoszykSelectedVehicle.SalonName && n.Booked == KoszykSelectedVehicle.Booked).FirstOrDefault(); BookedVehicles.Remove(vehicle); foreach (var salon in salonContainer.salons) { var vehicleItem = salon.CarList.Where(n => n.Model == KoszykSelectedVehicle.Model && n.Mark == KoszykSelectedVehicle.Mark && n.Price == KoszykSelectedVehicle.Price && n.ProductionYear == KoszykSelectedVehicle.ProductionYear && n.SalonName == KoszykSelectedVehicle.SalonName && n.Booked == KoszykSelectedVehicle.Booked).FirstOrDefault(); if (vehicleItem != null) { vehicleItem.Booked = false; _vehicleControler.UpdateVehicle(vehicleItem); } } } catch (NullReferenceException ex) { MessageBox.Show("{0}", ex.Message); } FillKoszykList(); VehicleListData.Rows.Clear(); FillVehicleListData(); }