C# 集成paypal 支付 例子

C# 集成paypal 支付 例子         //Post back to either sandbox or live         string strSandbox = "https://www.sandbox.paypal.com/cgi-bin/webscr";         string strLive = "https://www.paypal.com/cgi-bin/webscr";         HttpWebRequest req = (HttpWebRequest)WebRequest.Create(strSandbox);         //Set values for the request back         req.Method = "POST";         req.ContentType = "application/x-www-form-urlencoded";         byte[] param = Request.BinaryRead(HttpContext.Current.Request.ContentLength);         string strRequest = Encoding.ASCII.GetString(param);         string ipnPost = strRequest;         strRequest += "&cmd=_notify-validate";