lyfz_repos/铂金版源码/WFtpClient/netftp-2015/Examples/BeginGetFileSize.cs

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() {
            // The using statement here is OK _only_ because m_reset.WaitOne()
            // causes the code to block until the async process finishes, otherwise
            // the connection object would be disposed early. In practice, you
            // typically would not wrap the following code with a using statement.
            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();
            }
        }
    }
}