private void chkHistory_Checked(object sender, RoutedEventArgs e)
        {
            try
            {
                chkHistory.IsEnabled = false;

                prmHistory = new PromoHistory();
                pnlPromoVouchContent.Child = prmHistory;
                prmHistory.Margin          = new Thickness(0);
            }
            catch (Exception ex)
            {
                ExceptionManager.Publish(ex);
            }
            finally
            {
                chkHistory.IsEnabled = true;
            }
        }
        private void chkHistory_Checked(object sender, RoutedEventArgs e)
        {
            try
            {
                chkHistory.IsEnabled = false;

                prmHistory = new PromoHistory();
                pnlPromoVouchContent.Child = prmHistory;
                prmHistory.Margin = new Thickness(0);
            }
            catch (Exception ex)
            {
                ExceptionManager.Publish(ex);
            }
            finally
            {
                chkHistory.IsEnabled = true;
            }
        }