POST提交数据，一直返回【远程服务器返回错误: (403) 已禁止。】

    private string PostXml(string url, string strPost)

    {

        string result = "";



        StreamWriter myWriter = null;



        HttpWebRequest objRequest = (HttpWebRequest)WebRequest.Create(url);

        objRequest.Method = "POST";

        objRequest.ContentLength = strPost.Length;

        objRequest.ContentType = "text/xml";

        objRequest.Accept = "*/*";

        objRequest.UserAgent = "Mozilla/4.0 (compatible; MSIE 6.0; Windows NT 5.1; SV1; .NET CLR 1.1.4322)";

        objRequest.ServicePoint.Expect100Continue = true;

        objRequest.KeepAlive = true;

        try

        {

            myWriter = new StreamWriter(objRequest.GetRequestStream());

            myWriter.Write(strPost);

        }

        catch (Exception e)

        {

            return e.Message;

        }

        finally

        {

            myWriter.Close();

        }



        HttpWebResponse objResponse = (HttpWebResponse)objRequest.GetResponse();//此处异常

        using (StreamReader sr = new StreamReader(objResponse.GetResponseStream()))

        {

            result = sr.ReadToEnd();

            sr.Close();

        }

        return result;

    }