请教WinForm通过HttpWebRequest调用远程地址报403错误

jasonlee0927 2015-07-07 04:49:57

我在WinForm里要通过HttpWebRequest请求服务器Web站点上的一个xml配置文件，HttpWebRequest第一次请求的时候没有问题，能正常请求，但是再次请求的时候就报异常：远程服务器返回错误：(403)已禁止。而且断点调试都断不到，运行就直接报异常了，都不会进HttpWebRequest请求里面。



 /// <summary>

        /// 检查是否有自动更新

        /// </summary>

        private void CheckUpgrade()

        {

            bool canUpgrade = false;

            worker = new BackgroundWorker();

            worker.DoWork +=worker_DoWork;

            worker.RunWorkerCompleted+=worker_RunWorkerCompleted;

            DateTime now = DateTime.Now;

            TimeSpan ts = now.Subtract(UpgradeConfig.LastUpgradeTime);

            if (ts.Days == UpgradeConfig.UpgradeInterval)

            {

                canUpgrade = true;

            }

            if (canUpgrade)

            {

                worker.RunWorkerAsync();

            }

        }

        

        private void worker_RunWorkerCompleted(object sender, RunWorkerCompletedEventArgs e)

        {

            if (e.Error != null)

            {

                MessageBox.Show("检查软件版本更新异常!" + e.Error.Message); //报异常是这里

                return;

            }

            if (hasNewVersion)

            {

                if (MessageBox.Show("检测到新版本，请更新!", "更新提示", MessageBoxButtons.OK) == DialogResult.OK)

                {

                    string startupPath = AppDomain.CurrentDomain.SetupInformation.ApplicationBase;

                    Process.Start(System.IO.Path.Combine(startupPath, "T3FX.Upgrade.exe"));

                    worker.Dispose();

                    Application.Exit();

                }

            }

        }



        private void worker_DoWork(object sender, DoWorkEventArgs e)

        {

            try

            {

                string url = "http://192.168.1.250/upgrade/rms/upgrade.xml";// UpgradeConfig.UpgradeServer + @"/upgrade.xml";

                string localPath = Application.StartupPath + @"\upgrade.xml";

                UpgradeFileConfig upgradeFiles = null;

                HttpWebRequest webRequest = HttpWebRequest.Create(url) as HttpWebRequest;

                webRequest.Method = "GET";

                webRequest.Timeout = 1000 * 20;

                webRequest.ContentType = "application/xml";

                webRequest.Accept = "text/html,application/xhtml+xml,application/xml;q=0.9,*/*;q=0.8";

                webRequest.UserAgent = "Code Sample Web Client";

                HttpWebResponse webResponse = webRequest.GetResponse() as HttpWebResponse;



                using (Stream stream = webResponse.GetResponseStream())

                {

                    XmlSerializer serializer = new XmlSerializer(typeof(UpgradeFileConfig));

                    upgradeFiles = serializer.Deserialize(stream) as UpgradeFileConfig;

                    if (upgradeFiles != null)

                    {

                        if (!upgradeFiles.VersionNo.Equals(UpgradeConfig.VersionNo))

                        {

                            hasNewVersion = true;

                        }

                    }

                    webResponse.Close();

                }

                if (upgradeFiles != null)

                {

                    XmlSerializer serializerTo = new XmlSerializer(typeof(UpgradeFileConfig));

                    using (Stream stream = new FileStream(localPath, FileMode.OpenOrCreate, FileAccess.ReadWrite, FileShare.ReadWrite))

                    {

                        serializerTo.Serialize(stream, upgradeFiles);

                    }

                }

            }

            catch (Exception ex)

            {

                MessageBox.Show("下载更新配置文件异常!" + ex.Message);

            }

        }