public class AsyncFtpClient : FtpClient 

AsyncFtpClient client = new AsyncFtpClient();

// When using the AsyncFtpClient class, you can instruct
// the library to automatically redirect events on the main UI thread
// by setting the SynchronizingObject property.
client.SynchronizingObject = m_resultForm;

try
{
    // Start connecting asynchronously.
    IAsyncResult result = client.BeginConnect( hostname, new AsyncCallback( ConnectCompleted ), client );
}
catch( Exception except )
{
    console.WriteLine( except.Message );
}

private void ConnectCompleted( IAsyncResult result )
{
    AsyncFtpClient client = result.AsyncState as AsyncFtpClient;
    
    try
    {
        // All Begin calls must be matched by their End call.
        client.EndConnect( result );
         
        // Now that we are connected, let's login anonymously, but again using the async method call.
        client.BeginLogin( new AsyncCallback( LoginCompleted ), client );
    }
    catch( Exception except )
    {
        Console.WriteLine( except.Message );
    }
}

private void LoginCompleted( IAsyncResult result )
{
    AsyncFtpClient client = result.AsyncState as AsyncFtpClient;
    
    try
    {
        // All Begin calls must be matched by their End call.
        client.EndLogin( result );
        
        // Finally, we disconnect asynchronously. You can see that if you
        // wish to perform more operations, a cascading series of async
        // calls can get out of hand.
        client.BeginDisconnect( new AsyncCallback( DisconnectCompleted ), client );
        
     }
     catch( Exception except )
     {
         Console.WriteLine( except.Message );
     }
}

private void DisconnectCompleted( IAsyncResult result )
{
   AsyncFtpClient client = result.AsyncState as AsyncFtpClient;
   
   try
   {
       // All Begin calls must be matched by their End call.
       client.EndDisconnect( result );
   }
   catch( Exception except )
   {
       Console.WriteLine( except.Message );
   }
}

AsyncFtpClient client = new AsyncFtpClient();

// When using the AsyncFtpClient class, you can instruct
// the library to automatically redirect events on the main UI thread
// by setting the SynchronizingObject property.
client.SynchronizingObject = m_resultsForm;

try
{
    // Start connecting asynchronously. No need for a callback!
    IAsyncResult result = client.BeginConnect( hostname, null, null );
    
    // Wait for that async result to complete, making sure to pump messages.
    while( !result.IsCompleted )
        Application.DoEvents();
        
    // Complete the connection. All "Begin" calls must be matched by their matching "End" method call.
    client.EndConnect( result );
    
    // Now that we are connected, we can login.
    result = client.BeginLogin( null, null );
    
    while( !result.IsCompleted )
        Application.DoEvents();
        
    client.EndLogin( result );
    
    // And finally, we disconnect.
    result = client.BeginDisconnect( null, null );
    
    while( !result.IsCompleted )
        Application.DoEvents();
        
    client.EndDisconnect( result );
}    
catch( Exception except )
{
    Console.WriteLine( except.Message );
}