ASP.NET - Javascript timeOut Warning based on sessionState timeOut in web.config

Question

Problem: I am looking to create a time-out warning message on an asp.net page with a c# code behind based off my webconfig sessionState TimeOut Attribute.

Code on w

Answer 1

I've done this before by creating a web method in my code-behind file that checks for the timeout. Have your Javascript function get the timeout information via AJAX and display a warning according.

Example

This is the web method in my code-behind:

[WebMethod]
public static bool HasSessionTimedOut()
{
    HttpSessionState session = HttpContext.Current.Session;

    // I put this value into Session at the beginning.
    DateTime? sessionStart = session[SessionKeys.SessionStart] as DateTime?;

    bool isTimeout = false;

    if (!sessionStart.HasValue)
    {
        isTimeout = true;
    }
    else
    {
        TimeSpan elapsed = DateTime.Now - sessionStart.Value;
        isTimeout = elapsed.TotalMinutes > session.Timeout;
    }

    return isTimeout;
}

And this is my Javascript:

So, this is pretty rudimentary. Every 30 seconds, my Javascript function sends an AJAX request to my web method using ASP.NET's PageMethods object. It checks for a return value of true in the callback, which indicates that a timeout has occurred, and takes the appropriate action.