c# 把网络文件下载到本地

 /// <summary>        /// 从URL地址下载文件到本地磁盘        /// </summary>        /// <param name="ToLocalPath">本地磁盘地址</param>        /// <param name="Url">URL网址</param>        /// <returns></returns>        public static long SaveFileFromUrl(string FileName, string Url)        {            long Value = 0;            WebResponse response = null;            Stream stream = null;            try            {                HttpWebRequest request = (HttpWebRequest)WebRequest.Create(Url);                response = request.GetResponse();                stream = response.GetResponseStream();                if (!response.ContentType.ToLower().StartsWith("text/"))                {                    SaveBinaryFile(response, FileName);                    Value = response.ContentLength;                }            }            catch (Exception err)            {                Value = 0;                string aa = err.ToString();            }            return Value;        }        /// <summary>        /// Save a binary file to disk.        /// </summary>        /// <param name="response">The response used to save the file</param>        // 将二进制文件保存到磁盘        private static bool SaveBinaryFile(WebResponse response, string FileName)        {            bool Value = true;            byte[] buffer = new byte[1024];            try            {                if (File.Exists(FileName))                    File.Delete(FileName);                Stream outStream = System.IO.File.Create(FileName);                Stream inStream = response.GetResponseStream();                int l;                do                {                    l = inStream.Read(buffer, 0, buffer.Length);                    if (l > 0)                        outStream.Write(buffer, 0, l);                }                while (l > 0);                outStream.Close();                inStream.Close();            }            catch            {                Value = false;            }            return Value;        }