从 Web 上的 FTP 文件夹(端口 80)获取列表到数组

>我正在尝试通过端口 80 将 FTP Web 文件夹中的文件列表获取到数组或列表中，然后下载特定的扩展名，但由于某种原因计数器始终为零。

public void GetFilesFromServer(string url, string extension=".mp3")
{
    List<string> files = new List<string>();
    try
    {
        //Create FTP request
        FtpWebRequest request = (FtpWebRequest)FtpWebRequest.Create(url);
        request.Method = WebRequestMethods.Ftp.ListDirectory;
        request.Credentials = new NetworkCredential("anonymous", "anonymous");
        request.UsePassive = true;
        request.UseBinary = true;
        request.KeepAlive = false;
        FtpWebResponse response = (FtpWebResponse)request.GetResponse();
        Stream responseStream = response.GetResponseStream();
        StreamReader reader = new StreamReader(responseStream);
        while (!reader.EndOfStream)
        {
            files.Add(reader.ReadLine());
        }
        //Clean-up
        reader.Close();
        responseStream.Close(); //redundant
        response.Close();
    }
    catch (Exception)
    {
       // MessageBox.Show("There was an error connecting to the FTP Server");
    }
    //If the list was successfully received, display it to the user
    //through a dialog
    if (files.Count != 0)
    {
        string folderPath = Path.Combine(AppDomain.CurrentDomain.BaseDirectory, "DownloadedFiles");
        WebClient wc = new WebClient();
        foreach (string file in files)
        {
            if(file.EndsWith(extension))
                wc.DownloadFile(url+"/"+file, Path.Combine(folderPath, file));
        }
    }
}

我的目标是将所有 .ext 文件放入一个数组中，但我无法获得列表

例如，文件夹是 http://url.com/folder 的。

但它未能请求

检查了解决方案，但它对我不起作用。