public NewStaffPage()
        {
            InitializeComponent();
            Title.Content       = "ADD NEW STAFF";
            StaffID.Text        = manage.Create_NewIdstaff_Auto();
            startwork.IsEnabled = false;
            startwork.Text      = DateTime.Today.ToString();

            combosex.ItemsSource = new List <string>()
            {
                "nu", "nam"
            };
            comboPosition.ItemsSource = new List <string> {
                "quan li", "thu ngan", "ban hang"
            };
            BitmapImage image = new BitmapImage();

            image.BeginInit();
            image.UriSource = new Uri("pack://application:,,/Images/Image.png");
            image.EndInit();
            imgStaff.Source = image;
            imgStaff.Tag    = null;

            StaffID.IsReadOnly    = true;
            startwork.DisplayDate = DateTime.Now;
        }