我试图让FTP服务器上的文件列表，然后一个该文件是否存在在本地系统上，如果它确实比较日期修改，如果FTP文件更新下载一张支票。

I'm trying to get a list of the files on an FTP server, then one by one check if that file exists on the local system and if it does compare the dates modified and if the ftp file is newer download it.

private void btnGo_Click(object sender, EventArgs e)
{
    string[] files = GetFileList();
    foreach (string file in files)
    {
        if (file.Length >= 5)
        {
            string uri = "ftp://" + ftpServerIP + "/" + remoteDirectory + "/" + file;
            Uri serverUri = new Uri(uri);

            CheckFile(file);
        }
    }
    this.Close();
}

public string[] GetFileList()
{
    string[] downloadFiles;
    StringBuilder result = new StringBuilder();
    WebResponse response = null;
    StreamReader reader = null;

    try
    {
        FtpWebRequest reqFTP = (FtpWebRequest)FtpWebRequest.Create(new Uri("ftp://" + ftpServerIP + "/" + remoteDirectory));
        reqFTP.UseBinary = true;
        reqFTP.Credentials = new NetworkCredential(ftpUserID, ftpPassword);
        reqFTP.Method = WebRequestMethods.Ftp.ListDirectoryDetails;
        reqFTP.Proxy = null;
        reqFTP.KeepAlive = false;
        reqFTP.UsePassive = false;
        response = reqFTP.GetResponse();
        reader = new StreamReader(response.GetResponseStream());

        string line = reader.ReadLine();
        while (line != null)
        {
            result.Append(line);
            result.Append("\n");
            line = reader.ReadLine();
        }
        result.Remove(result.ToString().LastIndexOf('\n'), 1);
        return result.ToString().Split('\n');
    }
    catch
    {
        if (reader != null)
        {
            reader.Close();
        }
        if (response != null)
        {
            response.Close();
        }
        downloadFiles = null;
        return downloadFiles;
    }
}

private void CheckFile(string file)
{
    string dFile = file;
    string[] splitDownloadFile = Regex.Split(dFile, " ");
    string fSize = splitDownloadFile[13];
    string fMonth = splitDownloadFile[14];
    string fDate = splitDownloadFile[15];
    string fTime = splitDownloadFile[16];
    string fName = splitDownloadFile[17];


    string dateModified = fDate + "/" + fMonth+ "/" + fYear;

    DateTime lastModifiedDF = Convert.ToDateTime(dateModified);

    string[] filePaths = Directory.GetFiles(localDirectory);

    // if there is a file in filePaths that is the same as on the server compare them and then download if file on server is newer
    foreach (string ff in filePaths)
    {

        string[] splitFile = Regex.Split(ff, @"\\");

        string fileName = splitFile[2];
        FileInfo fouFile = new FileInfo(ff);
        DateTime lastChangedFF = fouFile.LastAccessTime;
        if (lastModifiedDF > lastChangedFF) Download(fileName);
    }
}

在检查文件的方法，为每个文件（它们是.exe文件）我不断收到不同的结果，当我分割字符串，即一个文件的文件名是在第18栏另一个是在16等等。我还可以T总是得到文件的年份部分。

In the check file method, for each file (they are .exe files) I keep getting different results when I split the string i.e. for one file the file name was at column 18 another it was at 16 etc. I also can't always get the year portion of the file.

推荐答案

选项A：我建议你用处理其中的一些细节，你更高级别的FTP客户端库，有几个可能的选项是：

Option A: I'd recommend that you use a higher-level FTP client library that handles some of these details for you, a few likely options are:

选项B：要更直接地回答你的问题，我认为这个问题是这一行：

Option B: To answer your question more directly, I think the issue is with this line:

string[] splitDownloadFile = Regex.Split(dFile, " ");

这似乎是FTP服务器使用空格右对齐文件名。为了解决这个问题，我们要调整的正则表达式来消费领域之间的所有空格：

It seems like the FTP server is using spaces to right-align the filenames. To deal with that, we want to adjust the regex to consume all whitespace between the fields:

string[] splitDownloadFile = Regex.Split(dFile, "\s+");

...其中\ s表示任何空白字符（通常是制表符或空格），+意味着一个或多个的东西它的左侧。这不会处理边缘情形，如带空格的文件名。

...where \s stands for any whitespace character (usually tabs or spaces), and + means one or more of the thing to the left of it. This will not handle edge cases, such as file names with spaces in them.