Detect ASP.NET Session Timeout - ASP.NET_SessionId method not working - asp.net

Question

I'm trying to detect Asp.NET Session Timeout to redirect user to a timeout page; i've checked various methods, most of them similar to
http://aspalliance.com/520_Detecting_ASPNET_Session_Timeouts.2
(if Session.IsNewSession and ASP.NET_SessionId cookie exists, then is a timeout)
The problem is that the "ASP.NET_SessionId" cookie is always present for me, even if i just started debugging, thus giving me always a false timeout flag when starting the web site for the first time.
UPDATE:
For testing, i've just created an Empty Asp.NET Web Application with following codes:
BasePage.cs
using System;
using System.Web.UI;
namespace TestApp.classes
{
public class BasePage : Page
{
protected override void OnInit(EventArgs e)
{
base.OnInit(e);
if (Context.Session != null)
{
if (Session.IsNewSession)
{
string szCookieHeader = Request.Headers["Cookie"];
if ((null != szCookieHeader) && (szCookieHeader.IndexOf("ASP.NET_SessionId") >= 0))
{
Response.Redirect("sessionTimeout.htm");
}
}
}
}
}
}
Global.asax
using System;
namespace TestApp
{
public class Global : System.Web.HttpApplication
{
protected void Application_Start(object sender, EventArgs e)
{
}
protected void Session_Start(object sender, EventArgs e)
{
var a = "";
}
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)
{
var b = "";
}
protected void Application_End(object sender, EventArgs e)
{
}
}
}
WebForm1.aspx
using System;
using TestApp.classes;
namespace TestApp
{
public partial class WebForm1 : BasePage
{
protected void Page_Load(object sender, EventArgs e)
{
}
}
}
Web.config
<?xml version="1.0"?>
<configuration>
<system.web>
<compilation debug="true" targetFramework="4.5" />
<httpRuntime targetFramework="4.5" />
<sessionState timeout="1"></sessionState>
</system.web>
</configuration>
Then Hit F5, and i will be redirected to sessionTimeout.htm. Why?

Answer 1

You don't have to use cookie when you develop your website. There are other ways to store data, e.g. you can store the data specific to a user in database
Note that "Cookieless = false" attrubute of SessionState element in web.config which means the sessionID of the current session will be saved in the client machine as a cookie
<sessionState cookieless="true" />
Default settings for ASP.NET session state are defined in the machine.config file and can be overridden in the web.config file in the application's root folder. By ensuring that the above line appears in the root web.config file, you enable cookieless sessions
Refer http://msdn.microsoft.com/en-us/library/aa479314.aspx
So check only for Session.IsNewSession and disable cookie