The GetFolderContents and GetRawFolderContents methods of the FtpClient class as well as the BeginGetFolderContents/ EndGetFolderContents and BeginGetRawFolderContents/ EndGetRawFolderContents methods of the AsyncFtpClient class are used to list the contents of a folder on an FTP server.
All these methods retrieve the entire (or filtered) contents of the FTP server's current working folder; however, the GetFolderContents and BeginGetFolderContents/EndGetFolderContents methods will return a collection of FtpItemInfo objects while the GetRawFolderContents and BeginGetRawFolderContents/EndGetRawFolderContents methods will return an unprocessed, clear text list (StringList).
AsyncFtpClient's methods now call the corresponding synchronous methods on a background thread. For this reason, the AsyncFtpClient class is now considered obsolete. It is therefore recommended to use
FtpClient instead to improve code readability.
When using Xceed FTP for .NET in a WinForms application, it is recommended that a SynchronizingObject be assigned to the SynchronizingObject property of the FtpClient class.
For more information, jump to the WinForms applications and threading topic. All the methods above list the files from the FTP server's current working directory. If you want to list the files from another location, you could use the ChangeCurrentFolder or BeginChangeCurrentFolder/ EndChangeCurrentFolder, or ChangeToParentFolder or BeginChangeToParentFolder/ EndChangeToParentFolder methods to change the current working folder. The current working folder can be retrieved via the GetCurrentFolder or BeginGetCurrentFolder/ EndGetCurrentFolder methods.
Synchronous (blocking) and asynchronous (non-blocking) demonstration using FtpClient
The following example demonstrates how to list the entire contents of an FTP server's current working folder using the GetFolderContents method and provide logging information during the process using the CommandSent and ReplyReceived events. An asynchronous (non-blocking) demonstration is also available.
| VB.NET |
 Copy Code |
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Imports Xceed.Ftp
Dim ftp As New FtpClient()
' When using FtpClient, you can instruct
' the library to automatically redirect events on the main UI thread
' by setting the SynchronizingObject property.
client.SynchronizingObject = Me
AddHandler ftp.CommandSent, AddressOf Me.FTP_CommandSent
AddHandler ftp.ReplyReceived, AddressOf Me.FTP_ReplyReceived
ftp.Connect( "localhost" )
ftp.Login()
Dim items As FtpItemInfoList = "ftp://ftp.GetFolderContents(String.Empty">ftp.GetFolderContents(String.Empty)
Dim item As FtpItemInfo
For Each item In items
ListBox1.Items.Add( item.Type.ToString() + " " + item.Name )
Next item
ftp.Disconnect()
RemoveHandler ftp.CommandSent, AddressOf Me.FTP_CommandSent
RemoveHandler ftp.ReplyReceived, AddressOf Me.FTP_ReplyReceived
Private Sub FTP_CommandSent(ByVal sender As Object, ByVal e As CommandSentEventArgs)
ListBox1.Items.Add(">> " + e.Command)
End Sub
Private Sub FTP_ReplyReceived(ByVal sender As Object, ByVal e As ReplyReceivedEventArgs)
ListBox1.Items.Add("<< " + e.Reply.ToString())
End Sub
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| C# |
Copy Code |
using Xceed.Ftp;
FtpClient ftp = new FtpClient();
// When using FtpClient, you can instruct
// the library to automatically redirect events on the main UI thread
// by setting the SynchronizingObject property.
client.SynchronizingObject = this;
ftp.CommandSent += new CommandSentEventHandler( this.FTP_CommandSent );
ftp.ReplyReceived += new ReplyReceivedEventHandler( this.FTP_ReplyReceived );
ftp.Connect( "localhost" );
ftp.Login();
FtpItemInfoList items = ftp.GetFolderContents( string.Empty );
foreach( FtpItemInfo item in items )
{
listBox1.Items.Add( item.Type.ToString() + " " + item.Name );
}
ftp.Disconnect();
ftp.CommandSent -= new CommandSentEventHandler( this.FTP_CommandSent );
ftp.ReplyReceived -= new ReplyReceivedEventHandler( this.FTP_ReplyReceived );
private void FTP_CommandSent( object sender, CommandSentEventArgs e )
{
listBox1.Items.Add( ">> " + e.Command );
}
private void FTP_ReplyReceived( object sender, ReplyReceivedEventArgs e )
{
listBox1.Items.Add( "<< " + e.Reply.ToString() );
} |
Asynchronous (non-blocking) demonstration
AsyncFtpClient's methods now call the corresponding synchronous methods on a background thread. For this reason, the AsyncFtpClient class is now considered obsolete. It is therefore recommended to use
FtpClient and assign a SynchronizingObject to its
SynchronizingObject property to improve code readability.
The following example demonstrates how to list the entire contents of an FTP server's current working folder using the GetFolderContents method and provide logging information during the process using the CommandSent and ReplyReceived events. A synchronous (blocking) demonstration is also available.
To clarify the code, instead of using callbacks, we will wait for completion of the operation before calling the matching "End" method. More information is available in the WinForms application and threading topic.
| VB.NET |
Copy Code |
|
Imports Xceed.Ftp
Dim ftp As New AsyncFtpClient()
AddHandler ftp.CommandSent, AddressOf Me.FTP_CommandSent
AddHandler ftp.ReplyReceived, AddressOf Me.FTP_ReplyReceived
Dim result As IAsyncResult = ftp.BeginConnect("localhost", Nothing, Nothing)
While Not result.IsCompleted
Application.DoEvents()
End While
ftp.EndConnect( result )
result = ftp.BeginLogin( Nothing, Nothing )
While Not result.IsCompleted
Application.DoEvents()
End While
ftp.EndLogin( result )
result = ftp.BeginGetFolderContents( string.Empty, Nothing, Nothing )
While Not result.IsCompleted
Application.DoEvents()
End While
Dim items As FtpItemInfoList = ftp.EndGetFolderContents(result)
Dim item As FtpItemInfo
For Each item In items
ListBox1.Items.Add( item.Type.ToString() + " " + item.Name )
Next item
result = ftp.BeginDisconnect( Nothing, Nothing )
While Not result.IsCompleted
Application.DoEvents()
End While
ftp.EndDisconnect( result )
RemoveHandler ftp.CommandSent, AddressOf Me.FTP_CommandSent
RemoveHandler ftp.ReplyReceived, AddressOf Me.FTP_ReplyReceived
Private Sub FTP_CommandSent(ByVal sender As Object, ByVal e As CommandSentEventArgs)
ListBox1.Items.Add(">> " + e.Command)
End Sub
Private Sub FTP_ReplyReceived(ByVal sender As Object, ByVal e As ReplyReceivedEventArgs)
ListBox1.Items.Add("<< " + e.Reply.ToString())
End Sub
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| C# |
Copy Code |
using Xceed.Ftp;
AsyncFtpClient ftp = new AsyncFtpClient();
ftp.CommandSent += new CommandSentEventHandler( this.FTP_CommandSent );
ftp.ReplyReceived += new ReplyReceivedEventHandler( this.FTP_ReplyReceived );
IAsyncResult result = ftp.BeginConnect( "localhost", null, null );
while( !result.IsCompleted )
Application.DoEvents();
ftp.EndConnect( result );
result = ftp.BeginLogin( null, null );
while( !result.IsCompleted )
Application.DoEvents();
ftp.EndLogin( result );
result = ftp.BeginGetFolderContents( string.Empty, null, null );
while( !result.IsCompleted )
Application.DoEvents();
FtpItemInfoList items = ftp.EndGetFolderContents( result );
foreach( FtpItemInfo item in items )
{
listBox1.Items.Add( item.Type.ToString() + " " + item.Name );
}
result = ftp.BeginDisconnect( null, null );
while( !result.IsCompleted )
Application.DoEvents();
ftp.EndDisconnect( result );
ftp.CommandSent -= new CommandSentEventHandler( this.FTP_CommandSent );
ftp.ReplyReceived -= new ReplyReceivedEventHandler( this.FTP_ReplyReceived );
private void FTP_CommandSent( object sender, CommandSentEventArgs e )
{
listBox1.Items.Add( ">> " + e.Command );
}
private void FTP_ReplyReceived( object sender, ReplyReceivedEventArgs e )
{
listBox1.Items.Add( "<< " + e.Reply.ToString() );
} |
Things you should consider
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Are you using Xceed FTP for .NET in a WinForms application? Use the AsyncFtpClient class rather than the FtpClient class.
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Do you want the FTP server to initiate the data connection rather than the FTP client? Set the PassiveTransfer property to false.
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Do you want to decrease or increase the period of time after which an FTP operation should timeout? Change the value of the Timeout property.
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Do you want to create a log file of the FTP process? Set the TraceWriter property.
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Do you want to know the state of the FTP client? Check the Connected and Busy properties. You can also check the State property for specific state information.
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Do you want to know when a file's information is being listed/parsed and/or manually parse the listing? Handle the ParsingListingLine event. The ParsingListingLine event will not be raised by the GetRawFolderContents method.
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Do you want to display progress information? Handle the FileTransferStatus event.
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Do you want to abort the FTP operation? Call the Abort method.
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Do you want to prevent routers from prematurely closing the command channel while a long data transfer is taking place. Set the KeepAliveInterval property.