如何在asp.net中实现paypal express checkout

Question

我想在asp.net中实现paypal快速结账。现在我收到错误“安全标头无效”。

 // build request
        SetExpressCheckoutRequestDetailsType reqDetails = new SetExpressCheckoutRequestDetailsType();
        ServicePointManager.SecurityProtocol = SecurityProtocolType.Ssl3;
        ServicePointManager.ServerCertificateValidationCallback = delegate { return true; };

        // TODO: Be sure to update hosting address in Web.Config!!


    reqDetails.ReturnURL = "http://localhost:14797/WebSite2/success.aspx";
    reqDetails.CancelURL = "http://localhost:14797/WebSite2/cancel.aspx";
    reqDetails.NoShipping = "1";
    reqDetails.OrderTotal = new BasicAmountType()
    {
        currencyID = CurrencyCodeType.USD,
        Value = "10.00"
    };

    SetExpressCheckoutReq req = new SetExpressCheckoutReq()
    {
        SetExpressCheckoutRequest = new SetExpressCheckoutRequestType()
        {
            Version = PayPalAPIUtil.Version,
            SetExpressCheckoutRequestDetails = reqDetails
        }
    };

    // query PayPal and get token
    SetExpressCheckoutResponseType resp = PayPalAPIUtil.BuildPayPalWebservice().SetExpressCheckout(req);
    PayPalAPIUtil.HandleError(resp);

    // redirect user to PayPal
    Response.Redirect(string.Format("{0}?cmd=_express-checkout&token={1}",
        "https://www.sandbox.paypal.com/cgi-bin/webscr", resp.Token));