private void button_Click(object sender, RoutedEventArgs e)
        {
            MainWindowProgram window = new MainWindowProgram(false, studentId);

            window.Show();
            this.Close();
        }
 private void Button_Click(object sender, RoutedEventArgs e)
 {
     using (TestingEntities db = new TestingEntities())
     {
         User user = db.Users.FirstOrDefault(u => u.user_login == txtLogin.Text);
         //Проверяем правильность ввода данных
         if (user == null || txtPaasword.Password != user.user_password)
         {
             lblErr.Visibility = Visibility.Visible;
             lblErr.Visibility = Visibility.Visible;
             txtLogin.Clear();
             txtPaasword.Clear();
             txtLogin.Focus();
             return;
         }
         bool role;
         //Выбор интерфейса преподаватель/студент
         role = (user.Role.role_name == "Преподаватель") ? true : false;
         MainWindowProgram window = new MainWindowProgram(role, user.id);
         window.Show();
         this.Close();
     }
 }