FTP上传下载类

public class FtpOperation
    {
        public static void UploadFile(FileInfo fileinfo, string targetDir, string hostname, string username, string password, string reName)
        {
            //1. check target
            string target;
            if (targetDir.Trim() == "")
            {
                return;
            }
            target = Guid.NewGuid().ToString(); //使用临时文件名


            string URI = "FTP://" + hostname + "/" + targetDir + "/" + target;
            ///WebClient webcl = new WebClient();
            System.Net.FtpWebRequest ftp = GetRequest(URI, username, password);

            //设置FTP命令 设置所要执行的FTP命令，
            //ftp.Method = System.Net.WebRequestMethods.Ftp.ListDirectoryDetails;//假设此处为显示指定路径下的文件列表
            ftp.Method = System.Net.WebRequestMethods.Ftp.UploadFile;
            //指定文件传输的数据类型
            ftp.UseBinary = true;
            ftp.UsePassive = true;

            //告诉ftp文件大小
            ftp.ContentLength = fileinfo.Length;
            //缓冲大小设置为2KB
            const int BufferSize = 2048;
            byte[] content = new byte[BufferSize - 1 + 1];
            int dataRead;

            //打开一个文件流 (System.IO.FileStream) 去读上传的文件
            using (FileStream fs = fileinfo.OpenRead())
            {
                try
                {
                    //把上传的文件写入流
                    using (Stream rs = ftp.GetRequestStream())
                    {
                        do
                        {
                            //每次读文件流的2KB
                            dataRead = fs.Read(content, 0, BufferSize);
                            rs.Write(content, 0, dataRead);
                        } while (!(dataRead < BufferSize));
                        rs.Close();
                    }

                }
                catch (Exception ex) { }
                finally
                {
                    fs.Close();
                }

            }

            ftp = null;
            //设置FTP命令
            ftp = GetRequest(URI, username, password);
            ftp.Method = System.Net.WebRequestMethods.Ftp.Rename; //改名
            ftp.RenameTo = reName;
            //ftp.RenameTo = fileinfo.Name;
            try
            {
                ftp.GetResponse();
            }
            catch (Exception ex)
            {
                ftp = GetRequest(URI, username, password);
                ftp.Method = System.Net.WebRequestMethods.Ftp.DeleteFile; //删除
                ftp.GetResponse();
                throw ex;
            }
            finally
            {
                //fileinfo.Delete();
            }

            // 可以记录一个日志 "上传" + fileinfo.FullName + "上传到" + "FTP://" + hostname + "/" + targetDir + "/" + fileinfo.Name + "成功." );
            ftp = null;

            #region
            /*****
*FtpWebResponse
* ****/
            //FtpWebResponse ftpWebResponse = (FtpWebResponse)ftp.GetResponse();
            #endregion
        }

        public static  void Download(string filePath, string fileName, string ftpServerIP, string ftpUser, string ftpPwd)
        {
            FtpWebRequest reqFTP;
            try
            {
                //filePath = <<The full path where the file is to be created.>>,
                //fileName = <<Name of the file to be created(Need not be the name of the file on FTP server).>>
                FileStream outputStream = new FileStream(filePath + "\" + fileName, FileMode.Create);

                reqFTP = (FtpWebRequest)FtpWebRequest.Create(new Uri("ftp://" + ftpServerIP + "/" + fileName));
                reqFTP.Method = WebRequestMethods.Ftp.DownloadFile;
                reqFTP.UseBinary = true;
                reqFTP.Credentials = new NetworkCredential(ftpUser, ftpPwd);
                FtpWebResponse response = (FtpWebResponse)reqFTP.GetResponse();
                Stream ftpStream = response.GetResponseStream();
                long cl = response.ContentLength;
                int bufferSize = 2048;
                int readCount;
                byte[] buffer = new byte[bufferSize];

                readCount = ftpStream.Read(buffer, 0, bufferSize);
                while (readCount > 0)
                {
                    outputStream.Write(buffer, 0, readCount);
                    readCount = ftpStream.Read(buffer, 0, bufferSize);
                }

                ftpStream.Close();
                outputStream.Close();
                response.Close();
            }
            catch (Exception ex)
            {
                MessageBox.Show(ex.Message);
            }
        }

        public static string GetStringResponse(FtpWebRequest ftp)
        {
            //Get the result, streaming to a string
            string result = "";
            using (FtpWebResponse response = (FtpWebResponse)ftp.GetResponse())
            {
                long size = response.ContentLength;
                using (Stream datastream = response.GetResponseStream())
                {
                    using (StreamReader sr = new StreamReader(datastream, System.Text.Encoding.Default))
                    {
                        result = sr.ReadToEnd();
                        sr.Close();
                    }

                    datastream.Close();
                }

                response.Close();
            }

            return result;
        }

        public static FtpWebRequest GetRequest(string URI, string username, string password)
        {
            //根据服务器信息FtpWebRequest创建类的对象
            FtpWebRequest result = (FtpWebRequest)FtpWebRequest.Create(URI);
            //提供身份验证信息
            result.Credentials = new System.Net.NetworkCredential(username, password);
            //设置请求完成之后是否保持到FTP服务器的控制连接，默认值为true
            result.KeepAlive = true;
            return result;
        }
    }