string serverPath="http://127.0.0.1/file/order?id=10";

HttpWebRequest httpWebRequest = (HttpWebRequest)HttpWebRequest.Create(serverPath);
                httpWebRequest.Headers.Add("Translate:f");
                httpWebRequest.Credentials = CredentialCache.DefaultCredentials;

                HttpWebResponse httpWebResponse = (HttpWebResponse)httpWebRequest.GetResponse();

                Stream stream = null;
                stream = httpWebResponse.GetResponseStream();
                int fileSize = (int)httpWebResponse.ContentLength;

                byte[] buffer = new byte[fileSize];
                FileStream fileStream = File.Open(localDownLoadPath, System.IO.FileMode.Create, System.IO.FileAccess.Write);
                int length = stream.Read(buffer, 0, fileSize);
                long total = length;
                while (length > 0)
                {
                    fileStream.Write(buffer, 0, length);
                    length = stream.Read(buffer, 0, fileSize);
                    total += length;
                }

                fileStream.Close();

网址采用了伪静态，下载不了文件，不知有何办法？