private void btnKhuyenMai_Click(object sender, RoutedEventArgs e) { if (ucDanhSachKhuyenMai == null) { ucDanhSachKhuyenMai = new UserControlLibrary.UCDanhSachKhuyenMai(mTransit); } spNoiDung.Children.Clear(); ucDanhSachKhuyenMai.Height = spNoiDung.ActualHeight; ucDanhSachKhuyenMai.Width = spNoiDung.ActualWidth; spNoiDung.Children.Add(ucDanhSachKhuyenMai); }