C# 从FTP上下载指定文件到本机

        #region  下载
      　　private void btnDownload_Click(object sender, EventArgs e)
         {

            WebClient webClint = new WebClient();
            string url = this.lblRar.Text.Trim();

            string Dir = "";
            //选择文件的保存路径
            //添加窗体控件folderBrowserDialog1


            if (folderBrowserDialog1.ShowDialog() == DialogResult.OK)
            {
                Dir = folderBrowserDialog1.SelectedPath;//得到打开后选择的文件地址
                
                string fileName = url;// URL.Substring(URL.LastIndexOf("\") + 1); //被下载的文件名

                try
                {
                    DownLoad(Dir, fileName);
                    MessageBox.Show("下载成功，文件[ " + fileName + " ]也保存到[ " + Dir + " ]了，请查阅。");

                }
                catch (Exception exp)
                {
                    MessageBox.Show(exp.Message, "Error");
                }
            }
            
        }
        
        
        //下载文件
     　　private void DownLoad(string filePath, string fileName)
        {
            FtpWebRequest reqFTP;
            try
            {
                //设置文件下载后的保存路径（文件夹）：filePath
                //命名下载后的文件名（可与原文件名不同）：fileName
                FileStream outputStream = new FileStream(filePath + "\" + fileName, FileMode.Create);
                reqFTP = (FtpWebRequest)FtpWebRequest.Create(new Uri("ftp://211.149.156.137/feibiht/upLoad/rar/" + fileName));
                //指定执行下载命令
                reqFTP.Method = WebRequestMethods.Ftp.DownloadFile;
                reqFTP.UseBinary = true;
                FtpWebResponse response = (FtpWebResponse)reqFTP.GetResponse(); //返回FTP服务器响应         
                Stream ftpStream = response.GetResponseStream();//检索从FTP服务器上发送的响应数据的流               
                long cl = response.ContentLength;//获取从FTP服务器上接收的数据的长度
                int bufferSize = 2048;
                int readCount;
                byte[] buffer = new byte[bufferSize];
                readCount = ftpStream.Read(buffer, 0, bufferSize);//从当前流读取字节序列，并将此流中的位置提升读取的字节数
                while (readCount > 0)
                {
                    outputStream.Write(buffer, 0, readCount);//使用从缓冲区中读取的数据，将字节块写入该流
                    readCount = ftpStream.Read(buffer, 0, bufferSize);
                }
                //关闭两个流
                ftpStream.Close();
                outputStream.Close();
                response.Close();
            }
            catch (Exception ex)
            {
                MessageBox.Show(ex.Message);
            }
        }
        #endregion