private void Save_Btn_Click(object sender, RoutedEventArgs e) { this.Save_btn.IsEnabled = false; String firstname = firstnametxt.Text; String lastname = lastnametxt.Text; String username = usernametxt.Text; String password = passwordbox.Password; String phone = cellno.Text; String type = "nurse"; String gender = "female"; int payment = Convert.ToInt32(paymenttxt.Text); DateTime dob = new DateTime(); if (datepicker.SelectedDate != null) { dob = (DateTime)datepicker.SelectedDate; } String experience = experty.Text; if (!string.IsNullOrEmpty(firstname) && !string.IsNullOrEmpty(lastname) && !string.IsNullOrEmpty(username) && !string.IsNullOrEmpty(password) && !string.IsNullOrEmpty(phone) && !string.IsNullOrEmpty(datepicker.Text) && !string.IsNullOrEmpty(paymenttxt.Text) && !string.IsNullOrEmpty(experience)) { if (hmsfac.getUser(username) != null) { MessageBox.Show("Username already exists!", "Warning!", MessageBoxButton.OK, MessageBoxImage.Warning); return; } User u = new User(); u.user_name = username; u.user_password = password; u.user_type = type; Employee emp = new Employee(); emp.emp_firstname = firstname; emp.emp_lastname = lastname; emp.emp_phone = phone; emp.emp_salary = payment; emp.emp_dob = dob; emp.emp_gender = gender; emp.User = u; Nurse nurse = new Nurse(); nurse.nurse_experience = experience; nurse.Employee = emp; hmsfac.addNurse(nurse); nurselist.Add(nurse); firstnametxt.Text = ""; lastnametxt.Text = ""; usernametxt.Text = ""; passwordbox.Password = ""; cellno.Text = ""; paymenttxt.Text = ""; experty.Text = ""; datepicker.Text = ""; } else { MessageBox.Show("All fields are required.", "Reminder", MessageBoxButton.OK, MessageBoxImage.Warning); this.Save_btn.IsEnabled = true; return; } }