Code:
        public void Ping_Function(string hostname)
        {
            System.Net.NetworkInformation.Ping pinger = new System.Net.NetworkInformation.Ping();
            PingReply reply = pinger.Send(hostname);
            DisplayPingReplyInfo(reply);
            
            pinger.PingCompleted += new PingCompletedEventHandler(pinger_PingCompleted);
            pinger.SendAsync(hostname, "oreilly ping");
        }
        
        private void DisplayPingReplyInfo(PingReply reply)
        {
            if (reply.Status == IPStatus.Success)
            {
                string result = "Results from pinging " + reply.Address
                                + "\tFragmentation allowed?: " + !reply.Options.DontFragment
                                + "\tTime to live: " + reply.Options.Ttl
                                + "\tRoundtrip took: " + reply.RoundtripTime
                                + "\tStatus: " + reply.Status.ToString();
                 this.RichTextBoxPing.Text = result;
            }
            else
            {
                string result = reply.Status.ToString ();
                this.RichTextBoxPing.Text = result;
            }
        }
        private void pinger_PingCompleted(object sender, PingCompletedEventArgs e)
        {
            PingReply reply = e.Reply;
            DisplayPingReplyInfo(reply);
            
            string result;

            if(e.Cancelled)
            {
                result = "Ping for " + e.UserState.ToString() + " was cancelled";
                this.RichTextBoxPing.Text = result;
            }
            else if (e.Error != null)
            {
                result = "Exception thrown during ping: " + e.Error.ToString();
                this.RichTextBoxPing.Text = result;
            }
        }