C#.Net遍历远程文件夹下的所有文件

private string GetFileNames(string URI) {      
        WebClient wClient = new WebClient();
        FtpWebRequest FtpClient;
        Uri uri = new Uri(URI);
        FtpClient = (FtpWebRequest)WebRequest.Create(uri);
     
        FtpClient.Credentials.GetCredential(uri, "user").UserName = "zwc";
        FtpClient.Credentials.GetCredential(uri, "user").Password = "12345";
        FtpClient.Credentials.GetCredential(uri, "user").Domain   = "";
        FtpClient.Method = WebRequestMethods.Ftp.ListDirectory;

        FtpWebResponse response = (FtpWebResponse)FtpClient.GetResponse();          
        StreamReader stream = new StreamReader(response.GetResponseStream());
        return stream.ReadToEnd();
    }