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Posted 7 May 2002

FTP component written with fully managed code

, 7 May 2002
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A .NET FTP component

Recently, I needed to write a program which could automatically download files from an FTP server. Unfortunately the .NET Framework lacks good support for FTP services. Although a few companies have already written libraries which can be used directly, the price is really too high for poor men like me. As a result, I decided to write my own FTP library and here it is.


This FTP component is an incomplete implementation of my design nor has it been fully tested. Please keep in mind it may contain bugs or even design flaws.

Connect to FTP server

FtpSession session = new FtpSession();
session.Server = "localhost";
session.Port   = 21; //not required if using the default ftp port 21
session.Connect("anonymous", "");

Enum subdirectories and files

* It is possible an incorrect list will be returned.
* In this case, you need to add your own regular expression to 
* interpret the list result (try to find it within ftpdirectory.cs)
FtpDirectory root = session.RootDirectory;
foreach(FtpDirectory d in root.SubDirectories)
    //do something

    foreach(FtpFile f in root.Files)
        //do something

         * Only CurrentDirectory's item can be legally used.
         * Do not save down FtpDirectory and FtpFile for later use
         * unless you are sure they belongs to CurrentDirectory.
         * Here is some sample may cause problems
        FtpDirectory d1 = session.CurrentDirectory.FindSubdirectory("somesubdir");
        FtpDirectory d2 = session.CurrentDirectory.FindSubdirectory("othersubdir");
        session.CurrentDirectory = d2;
         * Following 2 line will cause problem since CurrentDirectory 
         * is not d1's parent anymore
        foreach(FtpDirectory d in d1) 

Change current directory

session.CurrentDirectory = somesubdirectory

Upload file

//Blocking call
//Async call using callback
session.CurrentDirectory.BeginPutFile("somelocalfile", +
    new FtpAsyncDelegate(yourcallback);
//Async call using event
session.EndPutFile += new FtpFileEventHandler(yourhandler);
    //Manually upload the file
    FileInfo fi = new FileInfo(localfilefullpath);
    Stream r = File.OpenRead(fi.FullName);

    // actually will return a FtpOutputDataStream object
    Stream w = session.CurrentDirectory.CreateDataStream(fi.Name); 
    int readed;
    byte[] buff = new byte[4096];
    while((readed=r.Read(buff, 0, 4096) != 0)
	    w.Write(buff, 0, readed);
    * Must call FtpDataStream.Close().
    * This is because it will try to read the file transfer 
    * result from FTP server.

Download file

//Blocking call
//Async call using callback
session.CurrentDirectory.BeginGetFile("someremotefile", + 
    new FtpAsyncDelegate(yourcallback);
//Async call using event
session.EngGetFile += new FtpFileEventHandler(yourhandler);

//Manually download a file
Stream r = File.OpenWrite(localfilepath);

    FtpFile remoteFile = session.CurrentDirectory.FindFile(remotefilename);
    Stream w = remoteFile.GetOutputDataStream();
    int readed;
    byte[] buff = new byte[4096];
    while((readed=r.Read(buff, 0, 4096) != 0)
        w.Write(buff, 0, readed);
    * Must call FtpDataStream.Close().
    * This is because it will try to read the file transfer 
    * result from FTP server.

Create a new file in ftp server

//method 1
//method 2
Stream s = session.CurrentDirectory.CreateFileStream(newfilename);
// do something with s

Delete a file from ftp server

//method 1
//method 2
IFtpItem item = session.CurrentDirectory.FindItem(remotefilename)
if(item != null)

Delete a subdirectory

//method 1

//method 2
IFtpItem item = session.CurrentDirectory.FindItem(sub directoryname)
if(item != null)

Refresh the content of ftp directory

* If you have saved down some some directory item(subdir or ftpfile).
* They will become invalid after you refresh the directory
FtpFile f = session.CurrentDirectory.FindFile(somefile);
// you can not leagally use f anymore after the following line

Rename a file or directory

IFtpItem item = session.FindItem(directoryorfile);
if(item != null)
    session.RenameSubitem(item, newname);

Known Limitations

  • No support for active mode
  • No support for proxy server


  • Removed FileCollection and DirectoryCollection
  • Added support for VB's for each statement
  • VB client can directly access FtpDirectory.Files and FtpDirectory.SubDirectories with for each statement now.

Please send me a email if you find any bugs. Please include at least a description of the bug you have found. It will be nice if a testing program or even a solution is included.

Have fun.


This article has no explicit license attached to it but may contain usage terms in the article text or the download files themselves. If in doubt please contact the author via the discussion board below.

A list of licenses authors might use can be found here


About the Author

Alex Kwok
Web Developer
Hong Kong Hong Kong
No Biography provided

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Comments and Discussions

GeneralCoping file to different directory in remote server Pin
jasocl3-Jul-06 23:11
memberjasocl3-Jul-06 23:11 
AnswerRe: Coping file to different directory in remote server Pin
stixoffire10-Apr-08 6:18
memberstixoffire10-Apr-08 6:18 
GeneralUNIX regex's not recognising all files returned by LIST command - fix supplied here!! Pin
Stewart Rae8-May-06 16:58
memberStewart Rae8-May-06 16:58 
GeneralRe: UNIX regex's not recognising all files returned by LIST command - fix supplied here!! Pin
Shorin_gr15-Jun-06 5:14
memberShorin_gr15-Jun-06 5:14 
GeneralRe: UNIX regex's not recognising all files returned by LIST command - fix supplied here!! Pin
AquaJo13-Jul-06 10:14
memberAquaJo13-Jul-06 10:14 
GeneralRe: UNIX regex's not recognising all files returned by LIST command - fix supplied here!! Pin
josias_c28-Oct-10 10:20
memberjosias_c28-Oct-10 10:20 
GeneralRe: UNIX regex's not recognising all files returned by LIST command - fix supplied here!! Pin
lesnikowski4-Jan-11 8:39
memberlesnikowski4-Jan-11 8:39 
GeneralCannot connect .. Help !! Pin
Star999919-Apr-06 18:18
memberStar999919-Apr-06 18:18 
I am trying to use this library in my application.
My Code is as follow:

Private Sub Form_Load()
	Private ftpsession As New Session

	Dim files As String
        Dim count As Integer

        Dim rootdir As FtpDirectory
        ftpsession.Server = ""
        ftpsession.Connect("User1", "test")

        rootdir = ftpsession.CurrentDirectory

        count = rootdir.Files.Count

	For Each file As FtpFile In ftpsession.CurrentDirectory.Files
            files += file.Name & " - "
        Label1.Text += " Folder : " & rootdir.Name
        Label1.Text += " >> Files : " & files & "----------- || "

End Sub

I already insert the function "ChangeDirectory()" in FTPSession.cs Class
like this..

public bool ChangeDirectory(string Pathname)
			FtpDirectory fDir = new FtpDirectory((SessionConnected)m_state);
			m_state.CurrentDirectory = fDir;
			return true;
		catch (Exception e)
			return false;

And also already copyed the following function in FTPDirectory.cs Class.

public void ForceCWDUpdate()
		m_fullPath = m_session.ControlChannel.PWD();
		if(m_fullPath == "/") 

			m_name = m_fullPath;

		string[] directories = m_fullPath.Split('/');
		m_name = directories[directories.Length-1];
		m_fullPath += "/";


And write these following lines in "MatchingListLine" Function in the FTPDirectory.cs Class

m = m_UnixListLineExpression3.Match(line);
return m;

My program can get files from the currentdirectory when I trying to connect to the FTP server within our LAN.

But I cannot connect to the the other FTP server over the Internet.
I break at this line:
f = ftpsession.ChangeDirectory("TEST1")

At that time :

Run-time exception thrown : KCommon.Net.FTP.FtpException - Failed to open data connecton.

What I need to change?
Any Idea? Please help me. I am in a tough situation.Frown | :(



-- modified at 23:04 Thursday 20th April, 2006
GeneralSubdirectory Pin
nmbvc2-Mar-06 6:01
membernmbvc2-Mar-06 6:01 
GeneralRe: Subdirectory Pin
therearefartoomanybens13-Dec-09 15:51
membertherearefartoomanybens13-Dec-09 15:51 
Questioncan't download demo file? Pin
Anonymous6-Oct-05 14:39
sussAnonymous6-Oct-05 14:39 
GeneralHi Alex Pin
santosh poojari14-Sep-05 21:40
membersantosh poojari14-Sep-05 21:40 
GeneralHelp!! Problem Kcommon GetFile Pin
Jugkrit_Emp@hotmail.com22-Aug-05 22:07
memberJugkrit_Emp@hotmail.com22-Aug-05 22:07 
GeneralRe: Help!! Problem Kcommon GetFile Pin
Anonymous29-Aug-05 1:58
sussAnonymous29-Aug-05 1:58 
Generalavoid blocking while reading response stream! Pin
[pascal]17-Aug-05 5:59
member[pascal]17-Aug-05 5:59 
GeneralRe: avoid blocking while reading response stream! Pin
cphexad13-Feb-07 4:44
membercphexad13-Feb-07 4:44 
GeneralHi Help needed Pin
NR_gopal3-Aug-05 2:40
memberNR_gopal3-Aug-05 2:40 
Generalunhandled exceptions Pin
[pascal]27-Jul-05 7:24
member[pascal]27-Jul-05 7:24 
Generalpatch for linux ftp list parsing Pin
[pascal]25-Jul-05 6:57
member[pascal]25-Jul-05 6:57 
GeneralRe: patch for linux ftp list parsing Pin
cwetzelberger8-May-07 5:41
membercwetzelberger8-May-07 5:41 
Generaluploading images to ftp using files Pin
v.venkannababu5-Jun-05 0:44
memberv.venkannababu5-Jun-05 0:44 
Generaldoesnt compile Pin
David Every3-Jun-05 13:20
sussDavid Every3-Jun-05 13:20 
QuestionHow to use this coding in ASP.NET ?? Pin
pathakmakrand@yahoo.com16-May-05 19:54
susspathakmakrand@yahoo.com16-May-05 19:54 
GeneralUnix Regular Expression Pin
SasquatP29-Mar-05 10:34
memberSasquatP29-Mar-05 10:34 
GeneralVPN performance problem-design flaw Pin
fmoldoveanu21-Mar-05 14:28
memberfmoldoveanu21-Mar-05 14:28 

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