Expiring of MVC Session : Checking if Session is Null in Base Controller

See more:

C#

MVC

session

I am creating a session in index method of a controller(inheriting base controller).

// this code in is index method of the controller
int maxValue= 100 ;// Hard coded this value here as of now..
Session["MySession"] = maxValue;

I am using this session to make some validations using Ajax call

[HttpPost]
public ActionResult IsLessThanMaxValue(int val)
{
if(Session["MySession"] as int > val)
return Json("false");
else
return Json("true");
}

Since I am using this session on every event of the page (blur , change via Ajax call) I have to determine first, whether its empty or not. I am trying it, to do in Base Controller
in the following function :

protected override void OnActionExecuting


In base controller I want to check if this session is null
If it does ... I need to it to redirect it to some other page.


I tried following solution :

protected override void OnActionExecuting(ActionExecutingContext filterContext)
{
// If session exists
if (filterContext.HttpContext.Session != null)
{
//if new session
if (filterContext.HttpContext.Session.IsNewSession)
{
string cookie = filterContext.HttpContext.Request.Headers["Cookie"];
//if cookie exists and sessionid index is greater than zero
if ((cookie != null) && (cookie.IndexOf("ASP.NET_SessionId") >= 0))
{
//redirect to desired session
//expiration action and controller
filterContext.Result = this.Redirect("Some Url");
return;
}
}
}
//otherwise continue with action
base.OnActionExecuting(filterContext);
}


But it doesn't work. It seems the following condition

(cookie.IndexOf("ASP.NET_SessionId") >= 0) needs to be changed as
(cookie.IndexOf("ASP.NET_SessionId")< 0)



So here are my questions
1) Do I need to reverse the mentioned condition ?
2) Is there a better approach to do this ? (I cannot add null check of session in Base Controller since when the page loads for the first time , it will remain as Null and i don't want my page to redirect OnLoad only) ?