PayPal API Http调用问题

Question

我已经为用户集成了一个选项,通过PayPal在我正在创建的网上商店进行在线购物.当我开始收到此错误时突然出现问题:

You must write ContentLength bytes to the request stream before calling [Begin]GetResponse. 

Http调用的代码如下:

   public string HttpCall(string NvpRequest)
        {
            string url = pEndPointURL;

            string strPost = NvpRequest + "&" + buildCredentialsNVPString();
            strPost = strPost + "&BUTTONSOURCE=" + HttpUtility.UrlEncode(BNCode);

            HttpWebRequest objRequest = (HttpWebRequest)WebRequest.Create(url);
            objRequest.Timeout = Timeout;
            objRequest.Method = "POST";
            objRequest.ContentLength = strPost.Length;

            try
            {
                using (StreamWriter myWriter = new StreamWriter(objRequest.GetRequestStream()))
                {
                    myWriter.Write(strPost.ToString());
                }
            }
            catch (Exception e)
            {

            }

            //Retrieve the Response returned from the NVP API call to PayPal. 
            HttpWebResponse objResponse = (HttpWebResponse)objRequest.GetResponse(); // this is the line where the exception occurs...
            string result;
            using (StreamReader sr = new StreamReader(objResponse.GetResponseStream()))
            {
                result = sr.ReadToEnd();
            }

            return result;
        }

有人可以帮我解决这个问题吗？它一天前工作正常,现在它给我这个错误？

Answer 1

好的,如果有人有兴趣,我可以通过在创建Web请求之前添加以下行来修复错误(我能够通过像这样下载到Tls12来修复它):

`ServicePointManager.SecurityProtocol = SecurityProtocolType.Tls12`;

干杯:-)

编辑试试这个:

 public string HttpCall(string NvpRequest)
    {
        string url = pEndPointURL;

        string strPost = NvpRequest + "&" + buildCredentialsNVPString();
        strPost = strPost + "&BUTTONSOURCE=" + HttpUtility.UrlEncode(BNCode);
        ServicePointManager.SecurityProtocol = SecurityProtocolType.Tls;
        // Try using Tls11 if it doesnt works for you with Tls
        HttpWebRequest objRequest = (HttpWebRequest)WebRequest.Create(url);
        objRequest.Timeout = Timeout;
        objRequest.Method = WebRequestMethods.Http.Post;
        objRequest.ContentLength = strPost.Length;
        try
        {

            using (StreamWriter myWriter = new StreamWriter(objRequest.GetRequestStream()))
            {
                myWriter.Write(strPost.ToString());
            }
        }
        catch (Exception e)
        {

        }

        //Retrieve the Response returned from the NVP API call to PayPal. 
        HttpWebResponse objResponse = (HttpWebResponse)objRequest.GetResponse();
        string result;
        using (StreamReader sr = new StreamReader(objResponse.GetResponseStream()))
        {
            result = sr.ReadToEnd();
        }

        return result;
    }