protected void ContinueButton_Clicked(object sender, EventArgs e)
    {
        bool success = false;
        string check= Convert.ToString(ShippingOptionRadio.SelectedValue);
        int shipping_option;
        if (check != "")
        {
            if (Int32.TryParse(ShippingOptionRadio.SelectedValue, out shipping_option))
            {
                success = true;
            }

            if (success)
            {
                CartDB db = new CartDB();
                if (db.CartUpdateShippingOption(CurrentCart.CartId, shipping_option))
                {
                    CurrentCart.MoveNextStep();
                    Response.Redirect(Constants.Pages.CHECKOUT);
                }
            }
        }
        else {
            checkthis = true;
        }
    }