C#不'；无法在FTP服务器上获取文件大小

当我想在ftp服务器上获得文件的大小时，我一无所获。

有人看到代码中有问题吗？

在我看来，这种方法是很好的

类别：

public string getFileSize(string fileName)
{
    try
    {
        ftpRequest = (FtpWebRequest)FtpWebRequest.Create(host + "/" + fileName);
        ftpRequest.Credentials = new NetworkCredential(user, pass);
        ftpRequest.UseBinary = true;
        ftpRequest.UsePassive = true;
        ftpRequest.KeepAlive = true;
        ftpRequest.Method = WebRequestMethods.Ftp.GetFileSize;
        ftpResponse = (FtpWebResponse)ftpRequest.GetResponse();
        ftpStream = ftpResponse.GetResponseStream();
        StreamReader ftpReader = new StreamReader(ftpStream);
        string fileInfo = null;
        try { while (ftpReader.Peek() != -1) { fileInfo = ftpReader.ReadToEnd(); } }
        catch (Exception ex) { Console.WriteLine(ex.ToString()); }
        ftpReader.Close();
        ftpStream.Close();
        ftpResponse.Close();
        ftpRequest = null;
        return fileInfo;
    }
    catch (Exception ex) { Console.WriteLine(ex.ToString()); }
    return "";
}

过程：

ftp ftpClientCheckFile = new ftp(@"ftp://******.******.fr", "***********", "********");
string ftpfileSize = ftpClientCheckFile.getFileSize(fileName);
if (ftpfileSize == localfilesize)
{
  this.Invoke(new Action(() => { MessageBox.Show(this, "*********", "***", MessageBoxButtons.OK, MessageBoxIcon.Information); }));
  ftpClientCheckFile = null;
}
else
{
  this.Invoke(new Action(() => { MessageBox.Show(this, "***** ", "*******", MessageBoxButtons.OK, MessageBoxIcon.Information); }));
}

谢谢你的帮助。

Console.WriteLine(ftpResponse.ContentLength.ToString());