asp.net的ftp的上传和下载

/// <summary>
/// FtpWeb 的摘要说明
/// </summary>
public class FtpWeb
{
    string ftpServerIP;
    string ftpRemotePath;
    string ftpUserID;
    string ftpPassword;
    string ftpURI;

    /// <summary>
    /// 连接FTP
    /// </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 FtpWeb(string FtpServerIP, string FtpRemotePath, string FtpUserID, string FtpPassword)
    {
        ftpServerIP = FtpServerIP;
        ftpRemotePath = FtpRemotePath;
        ftpUserID = FtpUserID;
        ftpPassword = FtpPassword;
        ftpURI = "ftp://" + ftpServerIP + "/" + ftpRemotePath + "/";
    }

    /// <summary>
    /// 上传
    /// </summary>
    /// <param name="filename"></param>
    public bool Upload(string filename, out string errorMsg)
    {
        errorMsg = "";
        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; //开辟2KB缓存区
        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();
            return true;
        }
        catch (Exception ex)
        {
            errorMsg = ex.Message;
            return false;
        }
    }

    /// <summary>
    /// 下载
    /// </summary>
    /// <param name="filePath"></param>
    /// <param name="fileName"></param>
    public bool Download(string filePath, string fileName, out string errorMsg)
    {
        errorMsg = "";
        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();
            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();
            return true;
        }
        catch (Exception ex)
        {
            errorMsg = ex.Message;
            return false;
        }
    } 
}