c# - 带有身份验证的 C# HTTP Post 的问题

Question

我正在尝试通过 HTTP Post 发送一些 XML。但是我收到 401 Unauthorized。有趣的是，当我通过浏览器访问 URL 时，我提供的用户名/密码是可以的。

这是我的方法签名:

        internal static string Send(string URL, string XMLdata, string RequestMethod, 
                                    string RequestUsername, string RequestPassword)

我试过这个作为方法体:

        string requestData = XMLdata;
        string responseData = "";

        StreamWriter myWriter = null;
        HttpWebRequest objRequest = (HttpWebRequest)WebRequest.Create(URL);

        objRequest.Method = RequestMethod;
        objRequest.PreAuthenticate = true;
        objRequest.ContentType = "application/x-www-form-urlencoded";//"text/xml";
        objRequest.Credentials = new NetworkCredential(RequestUsername, RequestPassword);;
        objRequest.ContentLength = requestData.Length;

        try
        {
            myWriter = new StreamWriter(objRequest.GetRequestStream());
            myWriter.Write(requestData);
        }
        finally
        {
            myWriter.Close();
        }

        StreamReader sr = null;

        try
        {
            HttpWebResponse objResponse = (HttpWebResponse)objRequest.GetResponse();
            sr = new StreamReader(objResponse.GetResponseStream());
            responseData = sr.ReadToEnd();
        }
        finally
        {
            if (sr != null)
                sr.Close();
        }

        return responseData;

还有这个:

        string result;

        using (var client = new WebClient())
        {
            Uri requestUri = new Uri(URL);
            CredentialCache cache = new CredentialCache();
            NetworkCredential nc = new NetworkCredential(RequestUsername, RequestPassword);
            cache.Add(requestUri, "Basic", nc);
            client.Credentials = cache;

            result = client.UploadString(requestUri, XMLdata);
        }

        return result;

两者都得到 401。我究竟做错了什么？提醒一下:当我通过浏览器访问 URL 时，它会提示输入用户名/密码，我提供的凭据就可以了。

到目前为止我对这个主题的阅读:

• HttpClient and forms authentication in C#
• Login to the page with HttpWebRequest
• HTTP POST Returns Error: 417 "Expectation Failed."
• HTTP Post XML document - server receives only first line
• POST to HTTPS authentication error
• C# Xml in Http Post Request Message Body

感谢您的帮助。

Answer 1

[应 OP 的要求，我正在将我的评论迁移到答案]

根据你的描述，我没有给你答案，但我有一个建议:使用 Fiddler查看请求和响应的外观，无论是浏览器请求成功还是编程请求失败。我怀疑您会突然发现不同之处。