private void reload_Product()
        {
            // this function run during laod form and manager update product
            BL.Product pro = new BL.Product();
            allProducts = new List<BL.Product>();
            allProducts = pro.selectAllProduct();
            foreach (BL.Product product in allProducts)
            {
                comboBox1.Items.Add(product.Product_Name1);

            }
        }