private void Window_Loaded(object sender, RoutedEventArgs e)
        {
            dpNgay.Text = DateTime.Now.ToShortDateString();

            cboCaTruc.ItemsSource       = xlLK.getDSCaTrucFirstNull();
            cboCaTruc.DisplayMemberPath = "TenCaTruc";
            cboCaTruc.SelectedValuePath = "IDCaTruc";
            cboCaTruc.SelectedIndex     = 0;
        }
        private void getDS()
        {
            clearControl();
            dg.ItemsSource = xl.getDSLapLich(xl.getDSLichKham()).ToList();

            cboNhanVien.ItemsSource       = xl.getDSNhanVienFirstNull();
            cboNhanVien.SelectedValuePath = "IDNhanVien";
            cboNhanVien.DisplayMemberPath = "HoTen";

            cboPhongKham.ItemsSource       = xl.getDSPhongKhamFirstNull();
            cboPhongKham.DisplayMemberPath = "TenPhongKham";
            cboPhongKham.SelectedValuePath = "IDPhongKham";
            cboPhongKham.SelectedIndex     = 0;

            cboCaTruc.ItemsSource       = xl.getDSCaTrucFirstNull();
            cboCaTruc.DisplayMemberPath = "TenCaTruc";
            cboCaTruc.SelectedValuePath = "IDCaTruc";
            cboCaTruc.SelectedIndex     = 0;

            txtMaLK.Text = xl.taoMaPK().ToString();
        }