private void Set_button_Click(object sender, RoutedEventArgs e) { if (AddressERROR.Visibility == Visibility.Hidden) { DateTime testDT = Test_datePicker.SelectedDate.Value; testDT = testDT.AddHours(Tools.ToInt(Test_hourComboBox.SelectedItem)); Tester tester = myBL.Available_testers_nearby(testDT, trainee.Address, trainee.Car_type, trainee.Gear_type).First(); int Min = tester.Address.Distance(trainee.Address); foreach (Tester t in myBL.Available_testers_nearby(testDT, trainee.Address, trainee.Car_type, trainee.Gear_type)) { if (t.Address.Distance(trainee.Address) < Min) tester = t; } Test test = new Test(trainee.ID, tester.ID, trainee.First_name + " " + trainee.Last_name, tester.First_name + " " + tester.Last_name, testDT, trainee.Address, trainee.Car_type, trainee.Gear_type); try { myBL.Add_test(test); MessageBox.Show("Test set", "Confirmation", MessageBoxButton.OK, MessageBoxImage.Information); } catch (Exception E) { MessageBox.Show(E.Message,"Error",MessageBoxButton.OK,MessageBoxImage.Stop); } MainWindow.myWindow.Close(); } }