public bool Upload(FileInfo localFile, string remoteFileName)
        {

            try
            {
                bool result = false;
                if (localFile.Exists)
                {
                    string url = Host.TrimEnd('/') + RemotePath + remoteFileName;
                    FtpWebRequest request = CreateRequest(url, WebRequestMethods.Ftp.UploadFile);
                    FtpWebResponse response = (FtpWebResponse)request.GetResponse();
                    //上传数据
                    using (Stream rs = request.GetRequestStream())
                    using (FileStream fs = localFile.OpenRead())
                    {
                     
                        byte[] buffer = new byte[4096];//4K
                        int count = fs.Read(buffer, 0, buffer.Length);
                        while (count > 0)
                        {
                            try
                            {
                                rs.Write(buffer, 0, count);
                                count = fs.Read(buffer, 0, buffer.Length);
                                //request.ServicePoint.ConnectionLeaseTimeout = 1000;
                            }
                            catch
                            {
                                request.ClientCertificates.Clear();
                                response.GetResponseStream().Close();
                                response.Close();
                                request.Abort();
                                fs.Seek(count, SeekOrigin.Begin);
                               // Thread.Sleep(150000);
                               // request.GetRequestStream().Close();
                               // rs.Close();
                                GetFileList();
                                Append(fs, remoteFileName);
                                如果出现异常就追加文件流
                            }
                        }
                        fs.Close();
                        result = true;
                    }
                    return result;
                }
            }
            catch (Exception ex)
            {
                throw new Exception(ex.Message);
 
            }
            throw new Exception(string.Format("本地文件不存在,文件路径:{0}", localFile.FullName));
        }
        /// <summary>
        /// 给FTP服务器上的文件追加内容
        /// </summary>
        /// <param name="stream">数据流(可通过设置偏移来实现从特定位置开始上传)</param>
        /// <param name="remoteFileName">FTP服务器上的文件</param>
        /// <returns>返回一个值,指示是否追加成功</returns>
        public bool Append(Stream stream, string remoteFileName)
        {
            bool result = false;
            int count=0;
            try
            {
                if (stream != null && stream.CanRead)
                {
                    //建立连接
                    string url = Host.TrimEnd('/') + RemotePath + remoteFileName;
                    FtpWebRequest request = CreateRequest(url, WebRequestMethods.Ftp.AppendFile);
                    using (Stream rs = request.GetRequestStream())
                    {
                        //上传数据
                        byte[] buffer = new byte[4096];//4K
                         count = stream.Read(buffer, 0, buffer.Length);
                        while (count > 0)
                        {
                            rs.Write(buffer, 0, count);
                            count = stream.Read(buffer, 0, buffer.Length);
                            bool zt = false;
                            while (zt == false)
                            {
                                    rs.Write(buffer, 0, count);
                                    count = stream.Read(buffer, 0, buffer.Length);
                            }