public void RefreshConnect()
        {
                new System.Timers.Timer(1000) { Enabled = true }.Elapsed += delegate
                {
                    var connected = CheckNet.CheckURL(StrSite.TestConnect);
                    while(connected)
                    if (connected)
                    {
                        CheckProcessClose.Enabled = true;
                        OffSite4Game.Enabled = true;
                        TracePing.Enabled = true;
                        Checker4Game.Enabled = true;
                        OffSiteForum.Enabled = true;
                        SupportGame.Enabled = true;
                        MRTDownload.Enabled = true;
                    }
                    else
                    {
                        CheckProcessClose.Enabled = false;
                        OffSite4Game.Enabled = false;
                        TracePing.Enabled = false;
                        Checker4Game.Enabled = false;
                        OffSiteForum.Enabled = false;
                        SupportGame.Enabled = false;
                        MRTDownload.Enabled = false;
                        Refresh();
                    }
                    Invoke(new MethodInvoker(() => { BadConnect.Visible = !connected; }));
                };
        }

Task.Factory.StartNew(() => RefreshConnect());

class ConnectionMonitor : IDisposable
{
    private bool urlAvailable = false;
    private bool isActive = false;
    private System.Threading.Timer timer;

    public string Url { get; private set; }

    public event EventHandler ConnectionStateChanged;

    public ConnectionMonitor(string checkingUrl) { Url = checkingUrl; }

    public void Start()
    {
        isActive = true;
        timer = new Timer(CheckUrl, null, 1000, Timeout.Infinite);
    }

    public void Stop()
    {
        isActive = false;
    }

    private void CheckUrl(object state)//сигнатура для TimerCalback
    {
        var checkResult = CheckNet.CheckURL(StrSite.TestConnect);
        if(checkResult ^ urlAvailable)
        {
            ConnectionStateChanged.Invoke(this, new EventArgs());
            urlAvailable = checkResult;
        }
        timer.Dispose();
        if(isActive)
            timer = new Timer(CheckUrl, null, 1000, Timeout.Infinite);
    }

    public void Dispose() { timer?.Dispose(); }
}