private void mnAreas_Click(object sender, RoutedEventArgs e)
        {
            ParamMaint itemMaint = new ParamMaint(Constants.INV_AREAS, eerrLib);

            itemMaint.Title = "Mantención de Areas";
            itemMaint.Show();
        }
        private void mnItem_Click(object sender, RoutedEventArgs e)
        {
            ParamMaint itemMaint = new ParamMaint(Constants.INV_ITEMS, eerrLib);

            itemMaint.Title = "Mantención de Items";
            itemMaint.Show();
        }