C# FTP 파일 가져오기 & 파일 존재여부

private bool FtpGetFile()
{
    bool rtnFlag = false;
    try
    {
        if (!System.IO.Directory.Exists(tempPath))
        {
            System.IO.Directory.CreateDirectory(tempPath);
        }
 
        Uri sourceFileUri = new Uri(ftpUri + programName);
 
        FtpWebRequest ftpWebRequest = WebRequest.Create(sourceFileUri) as FtpWebRequest;
        ftpWebRequest.UsePassive = false;
        ftpWebRequest.Credentials = new NetworkCredential(userID, userPW);
        ftpWebRequest.Method = WebRequestMethods.Ftp.DownloadFile;
 
        FtpWebResponse ftpWebResponse = ftpWebRequest.GetResponse() as FtpWebResponse;
 
        Stream sourceStream = ftpWebResponse.GetResponseStream();
        FileStream targetFileStream = new FileStream(tempPath + @"\" + programName, FileMode.Create, FileAccess.Write);
 
        byte[] bufferByteArray = new byte[1024];
 
        while (true)
        {
            int byteCount = sourceStream.Read(bufferByteArray, 0, bufferByteArray.Length);
 
            if (byteCount == 0)
            {
                break;
            }
 
            targetFileStream.Write(bufferByteArray, 0, byteCount);
        }
 
        targetFileStream.Close();
        sourceStream.Close();
        rtnFlag = true;
    }
    catch (Exception ex)
    {
        txtUpdateLog.AppendText("\n[ERROR] " + ex.Message + "\n\n");
    }
 
    return rtnFlag;
}

private bool FtpFileExsit()
{
    FtpWebRequest ftpWebRequest = WebRequest.Create(new Uri(ftpUri)) as FtpWebRequest;
    ftpWebRequest.Credentials = new NetworkCredential(this.userID, this.userPW);
    ftpWebRequest.UseBinary = true;
    ftpWebRequest.UsePassive = false;
    ftpWebRequest.Method = WebRequestMethods.Ftp.ListDirectoryDetails;
    FtpWebResponse response = null;
    string data = string.Empty;
    try
    {
        response = ftpWebRequest.GetResponse() as FtpWebResponse;
        if (response != null)
        {
            StreamReader streamReader = new StreamReader(response.GetResponseStream(), Encoding.Default);
            data = streamReader.ReadToEnd();
        }
    }
    catch (Exception ex)
    {
        txtUpdateLog.AppendText("\n[ERROR] " + ex.Message + "\n\n");
    }
    finally
    {
        if (response != null)
        {
            response.Close();
        }
    }
 
    string[] directorys = data.Split(new string[] { Environment.NewLine }, StringSplitOptions.RemoveEmptyEntries);
    return (from directory in directorys
            select directory.Split(new string[] { " " }, StringSplitOptions.RemoveEmptyEntries)
            into directoryInfos
            where directoryInfos[0][0] != 'd'
            select directoryInfos[8]).Any(name => name == programName);
}