C# TimerCallback return value error
<p>When I use <kbd>F11</kbd> debug, <code>NetStatus</code> value is <code>true</code>, but when I use <kbd>F5</kbd> debug, <code>NetStatus</code> value is <code>false</code>. Why? How do I fix it?</p>

<p>I don't know what time the <code>_connect</code> value changes.
Is this a multi-threading synchronization issue?</p>

<pre><code>namespace conn
{
    using System;
    using System.Collections.Generic;
    using System.Text;
    using System.Net;
    using System.Net.Sockets;
    using System.Threading;

    class Program
    {
        static void Main(string[] args)
        {
            wait_conn();
        }

        private static void wait_conn()
        {
            bool NetStatus = false;
            string DataS = "127.0.0.1";

            CheckIpConn conn = new CheckIpConn();
            conn.CheckIp(DataS);

            //Thread.Sleep(3000);
            NetStatus = conn.Connected;

            if (!NetStatus)
                Console.WriteLine(conn.Connected.ToString());

            Console.Read();
        }
    }

    public class CheckIpConn
    {
        private int _port = 135;
        private volatile bool _connect;
        private IPEndPoint _iPEndPoint;
        private TcpClient _client;
        private TimerCallback _timerCallBack;
        private System.Threading.Timer _timer;

        public bool Connected
        {
            get { return _connect; }
        }

        public void CheckIp(string Ip)
        {
            _iPEndPoint = new IPEndPoint(IPAddress.Parse(Ip), _port);
            _timerCallBack = new TimerCallback(CheckConnect);
            _timer = new System.Threading.Timer(_timerCallBack, null, 10, 1000);
            _timer.Dispose();
        }

        public void CheckConnect(object o)
        {
            try
            {
                _client = new TcpClient();
                _client.Connect(_iPEndPoint);
                _connect = true;
                _client.Close();
            }
            catch
            {
                _connect = false;
            }
        }
    }
}
</code></pre>
