ASP.Net สอบถามเกี่ยวกับการนับ User online บนหน้า Home หน่อยคับ

public class Global : System.Web.HttpApplication
    {

        protected void Application_Start(object sender, EventArgs e)
        {
            Application["OnlineNow"] = 0;
        }

        protected void Session_Start(object sender, EventArgs e)
        {
            Application.Lock();
            Application["OnlineNow"] = Application["OnlineNow"] = +1 ;
            Application.UnLock();
        }

        protected void Application_BeginRequest(object sender, EventArgs e)
        {

        }

        protected void Application_AuthenticateRequest(object sender, EventArgs e)
        {

        }

        protected void Application_Error(object sender, EventArgs e)
        {

        }

        protected void Session_End(object sender, EventArgs e)
        {
            Application.Lock();
            Application["OnlineNow"] = Application["OnlineNow"] = -1;
            Application.UnLock();
        }

        protected void Application_End(object sender, EventArgs e)
        {
            Application["OnlineNow"] = null;
        }
    }

protected void Page_Load(object sender, EventArgs e)
        {

            this.lblText.Text = Application["OnlineNow"]  +"<br>"+ "Online";

        }