private void UserControl_Unloaded(object sender, RoutedEventArgs e)
        {
            if (null != ping)
            {
                ping.OnReply -= Ping_OnReply;
                ping.Stop();
                ping.Dispose();
            }
            ping = null;

            if (null != timer)
            {
                timer.Tick -= timer_Tick;
                timer.Stop();
            }
            timer = null;
        }
        private void UserControl_Loaded(object sender, RoutedEventArgs e)
        {
            string host = ConfigManager.Instance.Plaza.SCW.Http.HostName;

            ping          = new NLib.Components.PingManager();
            ping.OnReply += Ping_OnReply;
            ping.Add(host);
            ping.Interval = 1000;
            ping.Start();

            UpdateUI();

            timer          = new DispatcherTimer();
            timer.Interval = TimeSpan.FromSeconds(1);
            timer.Tick    += timer_Tick;
            timer.Start();
        }