参考了网上一些代码，作了一些调整优化。

using System;  using System.Collections.Generic;  using System.Linq;  using System.Text;  using System.Net;  using System.IO;    public class FTPHelper  {      /// <summary>      /// FTP请求对象      /// </summary>      FtpWebRequest request = null;      /// <summary>      /// FTP响应对象      /// </summary>      FtpWebResponse response = null;      /// <summary>      /// FTP服务器地址      /// </summary>      public string ftpURI { get; private set; }      /// <summary>      /// FTP服务器IP      /// </summary>      public string ftpServerIP { get; private set; }      /// <summary>      /// FTP服务器默认目录      /// </summary>      public string ftpRemotePath { get; private set; }      /// <summary>      /// FTP服务器登录用户名      /// </summary>      public string ftpUserID { get; private set; }      /// <summary>      /// FTP服务器登录密码      /// </summary>      public string ftpPassword { get; private set; }        /// <summary>        /// 初始化      /// </summary>        /// <param name="FtpServerIP">FTP连接地址</param>        /// <param name="FtpRemotePath">指定FTP连接成功后的当前目录, 如果不指定即默认为根目录</param>        /// <param name="FtpUserID">用户名</param>        /// <param name="FtpPassword">密码</param>        public FTPHelper(string ftpServerIP, string ftpRemotePath, string ftpUserID, string ftpPassword)      {          this.ftpServerIP = ftpServerIP;          this.ftpRemotePath = ftpRemotePath;          this.ftpUserID = ftpUserID;          this.ftpPassword = ftpPassword;          this.ftpURI = "ftp://" + ftpServerIP + "/" + ftpRemotePath + "/";      }      ~FTPHelper()      {          if (response != null)          {              response.Close();              response = null;          }          if (request != null)          {              request.Abort();              request = null;          }      }      /// <summary>      /// 建立FTP链接,返回响应对象      /// </summary>      /// <param name="uri">FTP地址</param>      /// <param name="ftpMethod">操作命令</param>      /// <returns></returns>      private FtpWebResponse Open(Uri uri, string ftpMethod)      {          request = (FtpWebRequest)FtpWebRequest.Create(uri);          request.Method = ftpMethod;          request.UseBinary = true;          request.KeepAlive = false;          request.Credentials = new NetworkCredential(this.ftpUserID, this.ftpPassword);          return (FtpWebResponse)request.GetResponse();      }        /// <summary>             /// 建立FTP链接,返回请求对象             /// </summary>            /// <param name="uri">FTP地址</param>             /// <param name="ftpMethod">操作命令</param>             private FtpWebRequest OpenRequest(Uri uri, string ftpMethod)      {          request = (FtpWebRequest)WebRequest.Create(uri);          request.Method = ftpMethod;          request.UseBinary = true;          request.KeepAlive = false;          request.Credentials = new NetworkCredential(this.ftpUserID, this.ftpPassword);          return request;      }      /// <summary>      /// 创建目录      /// </summary>      /// <param name="remoteDirectoryName">目录名</param>      public void CreateDirectory(string remoteDirectoryName)      {          response = Open(new Uri(ftpURI + remoteDirectoryName), WebRequestMethods.Ftp.MakeDirectory);      }      /// <summary>      /// 更改目录或文件名      /// </summary>      /// <param name="currentName">当前名称</param>      /// <param name="newName">修改后新名称</param>      public void ReName(string currentName, string newName)      {          request = OpenRequest(new Uri(ftpURI + currentName), WebRequestMethods.Ftp.Rename);          request.RenameTo = newName;          response = (FtpWebResponse)request.GetResponse();      }         /// <summary>        /// 切换当前目录        /// </summary>        /// <param name="IsRoot">true:绝对路径 false:相对路径</param>         public void GotoDirectory(string DirectoryName, bool IsRoot)      {          if (IsRoot)              ftpRemotePath = DirectoryName;          else              ftpRemotePath += "/" + DirectoryName;            ftpURI = "ftp://" + ftpServerIP + "/" + ftpRemotePath + "/";      }             /// <summary>      /// 删除目录(包括下面所有子目录和子文件)      /// </summary>      /// <param name="remoteDirectoryName">要删除的带路径目录名：如web/test</param>      /*       * 例：删除test目录       FTPHelper helper = new FTPHelper("x.x.x.x", "web", "user", "password");                         helper.RemoveDirectory("web/test");       */      public void RemoveDirectory(string remoteDirectoryName)      {          GotoDirectory(remoteDirectoryName, true);          var listAll = ListFilesAndDirectories();          foreach (var m in listAll)          {              if (m.IsDirectory)                             RemoveDirectory(m.Path);                         else                             DeleteFile(m.Name);                     }          GotoDirectory(remoteDirectoryName, true);          response = Open(new Uri(ftpURI), WebRequestMethods.Ftp.RemoveDirectory);      }      /// <summary>      /// 文件上传      /// </summary>      /// <param name="localFilePath">本地文件路径</param>      public void Upload(string localFilePath)      {          FileInfo fileInf = new FileInfo(localFilePath);          request = OpenRequest(new Uri(ftpURI + fileInf.Name), WebRequestMethods.Ftp.UploadFile);          request.ContentLength = fileInf.Length;          int buffLength = 2048;          byte[] buff = new byte[buffLength];          int contentLen;          using (var fs = fileInf.OpenRead())          {              using (var strm = request.GetRequestStream())              {                  contentLen = fs.Read(buff, 0, buffLength);                  while (contentLen != 0)                  {                      strm.Write(buff, 0, contentLen);                      contentLen = fs.Read(buff, 0, buffLength);                  }              }          }      }      /// <summary>        /// 删除文件        /// </summary>        /// <param name="remoteFileName">要删除的文件名</param>      public void DeleteFile(string remoteFileName)      {          response = Open(new Uri(ftpURI + remoteFileName), WebRequestMethods.Ftp.DeleteFile);      }        /// <summary>      /// 获取当前目录的文件和一级子目录信息      /// </summary>      /// <returns></returns>      public List<FileStruct> ListFilesAndDirectories()      {          var fileList = new List<FileStruct>();          response = Open(new Uri(ftpURI), WebRequestMethods.Ftp.ListDirectoryDetails);          using (var stream = response.GetResponseStream())          {              using (var sr = new StreamReader(stream))              {                  string line = null;                  while ((line = sr.ReadLine()) != null)                  {                      //line的格式如下：                      //08-18-13  11:05PM       <DIR>          aspnet_client                      //09-22-13  11:39PM                 2946 Default.aspx                      DateTime dtDate = DateTime.ParseExact(line.Substring(0, 8), "MM-dd-yy", null);                      DateTime dtDateTime = DateTime.Parse(dtDate.ToString("yyyy-MM-dd") + line.Substring(8, 9));                      string[] arrs = line.Split(' ');                      var model = new FileStruct()                      {                          IsDirectory = line.IndexOf("<DIR>") > 0 ? true : false,                          CreateTime = dtDateTime,                          Name = arrs[arrs.Length - 1],                          Path = ftpRemotePath + "/" + arrs[arrs.Length - 1]                      };                      fileList.Add(model);                  }              }          }          return fileList;      }      /// <summary>             /// 列出当前目录的所有文件             /// </summary>             public List<FileStruct> ListFiles()      {          var listAll = ListFilesAndDirectories();          var listFile = listAll.Where(m => m.IsDirectory == false).ToList();          return listFile;      }      /// <summary>             /// 列出当前目录的所有一级子目录             /// </summary>             public List<FileStruct> ListDirectories()      {          var listAll = ListFilesAndDirectories();          var listFile = listAll.Where(m => m.IsDirectory == true).ToList();          return listFile;      }      /// <summary>             /// 判断当前目录下指定的子目录或文件是否存在             /// </summary>             /// <param name="remoteName">指定的目录或文件名</param>            public bool IsExist(string remoteName)      {          var list = ListFilesAndDirectories();          if (list.Count(m => m.Name == remoteName) > 0)              return true;          return false;      }      /// <summary>             /// 判断当前目录下指定的一级子目录是否存在             /// </summary>             /// <param name="RemoteDirectoryName">指定的目录名</param>            public bool IsDirectoryExist(string remoteDirectoryName)      {          var listDir = ListDirectories();          if (listDir.Count(m => m.Name == remoteDirectoryName) > 0)              return true;          return false;      }      /// <summary>             /// 判断当前目录下指定的子文件是否存在            /// </summary>             /// <param name="RemoteFileName">远程文件名</param>             public bool IsFileExist(string remoteFileName)      {          var listFile = ListFiles();          if (listFile.Count(m => m.Name == remoteFileName) > 0)              return true;          return false;      }        /// <summary>      /// 下载      /// </summary>      /// <param name="saveFilePath">下载后的保存路径</param>      /// <param name="downloadFileName">要下载的文件名</param>      public void Download(string saveFilePath, string downloadFileName)      {          using (FileStream outputStream = new FileStream(saveFilePath + "\\" + downloadFileName, FileMode.Create))          {              response = Open(new Uri(ftpURI + downloadFileName), WebRequestMethods.Ftp.DownloadFile);              using (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);                  }              }          }      }         }    public class FileStruct  {      /// <summary>      /// 是否为目录      /// </summary>      public bool IsDirectory { get; set; }      /// <summary>      /// 创建时间      /// </summary>      public DateTime CreateTime { get; set; }      /// <summary>      /// 文件或目录名称      /// </summary>      public string Name { get; set; }      /// <summary>      /// 路径      /// </summary>      public string Path { get; set; }  }