Download the latest file from an FTP server

I have to download the latest file from an FTP Server. I know how download the latest file from my computer, but I don't how download from an FTP server.

How can I download the latest file from a FTP Server?

This is my program to download the latest file from my Computer

public Form1()
    {
        InitializeComponent();

        string startFolder = @"C:\Users\user3\Desktop\Documentos XML";

        System.IO.DirectoryInfo dir = new System.IO.DirectoryInfo(startFolder);

        IEnumerable<System.IO.FileInfo> fileList = dir.GetFiles("*.*", System.IO.SearchOption.AllDirectories);

        IEnumerable<System.IO.FileInfo> fileQuerry =
            from file in fileList
            where file.Extension == ".txt"
            orderby file.CreationTimeUtc
            select file;

        foreach (System.IO.FileInfo fi in fileQuerry)
            {
                var newestFile =
                (from file in fileQuerry
                 orderby file.CreationTimeUtc
                 select new { file.FullName, file.Name })
                 .First();
                textBox2.Text = newestFile.FullName;
            }
    }

OK, with this code I know the date of the last file, but How I know the name of this file????????

You have to retrieve timestamps of remote files to select the latest one.

Unfortunately, there's no really reliable and efficient way to retrieve modification timestamps of all files in a directory using features offered by .NET framework, as it does not support the FTP MLSD command. The MLSD command provides a listing of remote directory in a standardized machine-readable format. The command and the format is standardized by RFC 3659.

Alternatives you can use, that are supported by .NET framework:

ListDirectoryDetails method (the FTP LIST command) to retrieve details of all files in a directory and then you deal with FTP server specific format of the details

DOS/Windows format: C# class to parse WebRequestMethods.Ftp.ListDirectoryDetails FTP response
*nix format: Parsing FtpWebRequest ListDirectoryDetails line
GetDateTimestamp method (the FTP MDTM command) to individually retrieve timestamps for each file. An advantage is that the response is standardized by RFC 3659 to YYYYMMDDHHMMSS[.sss]. A disadvantage is that you have to send a separate request for each file, what can be quite inefficient. This method uses the LastModified property that you mention:
```
const string uri = "ftp://example.com/remote/path/file.txt";
FtpWebRequest request = (FtpWebRequest)WebRequest.Create(uri);
request.Method = WebRequestMethods.Ftp.GetDateTimestamp;
FtpWebResponse response = (FtpWebResponse)request.GetResponse();
Console.WriteLine("{0} {1}", uri, response.LastModified);
```

Alternatively you can use a 3rd party FTP client implementation that supports the modern MLSD command.

For example WinSCP .NET assembly supports that.

There's even an example for your specific task: Downloading the most recent file.
The example is for PowerShell and SFTP, but translates to C# and FTP easily:

// Setup session options
SessionOptions sessionOptions = new SessionOptions
{
    Protocol = Protocol.Ftp,
    HostName = "example.com",
    UserName = "username",
    Password = "password",
};

using (Session session = new Session())
{
    // Connect
    session.Open(sessionOptions);

    // Get list of files in the directory
    string remotePath = "/remote/path/";
    RemoteDirectoryInfo directoryInfo = session.ListDirectory(remotePath);

    // Select the most recent file
    RemoteFileInfo latest =
        directoryInfo.Files
            .OrderByDescending(file => file.LastWriteTime)
            .First();

    // Download the selected file
    string localPath = @"C:\local\path\";
    string sourcePath = RemotePath.EscapeFileMask(remotePath + latest.Name);
    session.GetFiles(sourcePath, localPath).Check();
}

(I'm the author of WinSCP)