public IAsyncResult BeginGetFileSize(
	string path,
	AsyncCallback callback,
	Object state
)

Public Function BeginGetFileSize ( 
	path As String,
	callback As AsyncCallback,
	state As Object
) As IAsyncResult

public:
virtual IAsyncResult^ BeginGetFileSize(
	String^ path, 
	AsyncCallback^ callback, 
	Object^ state
) sealed

using System;
using System.Net;
using System.Net.FtpClient;
using System.Threading;

namespace Examples {
    public static class BeginGetFileSizeExample {
        static ManualResetEvent m_reset = new ManualResetEvent(false);

        public static void BeginGetFileSize() {
            using (FtpClient conn = new FtpClient()) {
                m_reset.Reset();

                conn.Host = "localhost";
                conn.Credentials = new NetworkCredential("ftptest", "ftptest");
                conn.Connect();
                conn.BeginGetFileSize("foobar", new AsyncCallback(BeginGetFileSizeCallback), conn);

                m_reset.WaitOne();
                conn.Disconnect();
            }
        }

        static void BeginGetFileSizeCallback(IAsyncResult ar) {
            FtpClient conn = ar.AsyncState as FtpClient;

            try {
                if (conn == null)
                    throw new InvalidOperationException("The FtpControlConnection object is null!");

                Console.WriteLine("File size: {0}", conn.EndGetFileSize(ar));
            }
            catch (Exception ex) {
                Console.WriteLine(ex.ToString());
            }
            finally {
                m_reset.Set();
            }
        }
    }
}