使用.net FtpWebRequest 實現FTP常用功能

using System;
using System.Collections.Generic;
using System.Text;
using System.IO;
using System.Net;
using System.Windows.Forms;
using System.Globalization;

namespace FtpTest1
{

    public class FtpWeb
    {
        string ftpServerIP;
        string ftpRemotePath;
        string ftpUserID;
        string ftpPassword;
        string ftpURI;

        /// <summary>
        /// 連接FTP
        /// </summary>
        /// <param name="FtpServerIP">FTP連接地址</param>
        /// <param name="FtpRemotePath">指定FTP連接成功後的當前目錄, 如果不指定即默認為根目錄</param>
        /// <param name="FtpUserID">用戶名</param>
        /// <param name="FtpPassword">密碼</param>
        public FtpWeb(string FtpServerIP, string FtpRemotePath, string FtpUserID, string FtpPassword)
        {
            ftpServerIP = FtpServerIP;
            ftpRemotePath = FtpRemotePath;
            ftpUserID = FtpUserID;
            ftpPassword = FtpPassword;
            ftpURI = "ftp://" + ftpServerIP + "/" + ftpRemotePath + "/";
        }

        /// <summary>
        /// 上傳
        /// </summary>
        /// <param name="filename"></param>
        public void Upload(string filename)
        {
            FileInfo fileInf = new FileInfo(filename);
            string uri = ftpURI + fileInf.Name;
            FtpWebRequest reqFTP;

            reqFTP = (FtpWebRequest)FtpWebRequest.Create(new Uri(uri));
            reqFTP.Credentials = new NetworkCredential(ftpUserID, ftpPassword);
            reqFTP.KeepAlive = false;
            reqFTP.Method = WebRequestMethods.Ftp.UploadFile;
            reqFTP.UseBinary = true;
            reqFTP.ContentLength = fileInf.Length;
            int buffLength = 2048;
            byte[] buff = new byte[buffLength];
            int contentLen;
            FileStream fs = fileInf.OpenRead();
            try
            {
                Stream strm = reqFTP.GetRequestStream();
                contentLen = fs.Read(buff, 0, buffLength);
                while (contentLen != 0)
                {
                    strm.Write(buff, 0, contentLen);
                    contentLen = fs.Read(buff, 0, buffLength);
                }
                strm.Close();
                fs.Close();
            }
            catch (Exception ex)
            {
                Insert_Standard_ErrorLog.Insert("FtpWeb", "Upload Error --> " + ex.Message);
            }
        }

        /// <summary>
        /// 下載
        /// </summary>
        /// <param name="filePath"></param>
        /// <param name="fileName"></param>
        public void Download(string filePath, string fileName)
        {
            FtpWebRequest reqFTP;
            try
            {
                FileStream outputStream = new FileStream(filePath + "\" + fileName, FileMode.Create);

                reqFTP = (FtpWebRequest)FtpWebRequest.Create(new Uri(ftpURI + fileName));
                reqFTP.Method = WebRequestMethods.Ftp.DownloadFile;
                reqFTP.UseBinary = true;
                reqFTP.Credentials = new NetworkCredential(ftpUserID, ftpPassword);
                FtpWebResponse response = (FtpWebResponse)reqFTP.GetResponse();
                Stream ftpStream = response.GetResponseStream();