Session timeout during using the application

Question

currently I'm programming a web application, but some colleagues sometimes mention, that they get a session timeout during working with the web application. I can't reproduce the error and not sure about what could be the error. Because the actively working the have enough page loads so that the time since the last click is shorter than the timeout of 15 minutes. What else could be the reason?

Web.config:

<sessionState mode="InProc" timeout="3" customProvider="DefaultSessionProvider">

Autoredirect c#:

public partial class AutoRedirect : System.Web.UI.UserControl
    {
        public string LoginDate;
        public string ExpressDate;
        protected void Page_Load(object sender, EventArgs e)
        {
            string PageName = Path.GetFileName(Request.Url.AbsolutePath);

            // Check session is expire or timeout.
            if (Session["username"] == null)
            {
                if (PageName != Constants.defaultPage && PageName != Constants.loginPage)
                {
                    Response.Redirect(Constants.defaultPage);
                }
            }

            // Get user login time or last activity time.
            DateTime date = DateTime.Now;
            LoginDate = date.ToString("u", DateTimeFormatInfo.InvariantInfo).Replace("Z", "");
            int sessionTimeout = Session.Timeout;
            DateTime dateExpress = date.AddMinutes(sessionTimeout);
            ExpressDate = dateExpress.ToString("u", DateTimeFormatInfo.InvariantInfo).Replace("Z", "");
        }
    }

AutoRedirect ascx:

<script type="text/javascript">
    var timeRefresh;
    var timeInterval;
    var currentTime;
    var expressTime;

    expressTime = "<%=ExpressDate %>";
    currentTime = "<%=LoginDate %>";
    setCookie("express", expressTime);
    timeRefresh = setInterval("Refresh()", 1000);

    // Refresh this page to check session is expire or timeout.
    function Refresh() {
        var current = getCookie("express");
        var date = current.split(" ")[0];
        var time = current.split(" ")[1];
        var scriptDate = new Date();
        var year = scriptDate.getFullYear();
        var month = scriptDate.getMonth() + 1;
        var day = scriptDate.getDate();
        var hour = scriptDate.getHours();
        var min = scriptDate.getMinutes();
        var second = scriptDate.getSeconds();
        if (Date.UTC(year, month, day, hour, min, second) >=
           Date.UTC(date.split("-")[0], date.split("-")[1], date.split("-")[2],
           time.split(":")[0], time.split(":")[1], time.split(":")[2])) {
            clearInterval(timeRefresh);
            Redirect();
        }
    }

    function Redirect() {
        window.location.replace("Login.aspx?s=ex");
    }

    // Retrieve cookie by name.
    function getCookie(name) {
        var arg = name + "=";
        var aLen = arg.length;
        var cLen = document.cookie.length;
        var i = 0;
        while (i < cLen) {
            var j = i + aLen;
            if (document.cookie.substring(i, j) == arg) {
                return getCookieVal(j);
            }
            i = document.cookie.indexOf(" ", i) + 1;
            if (i == 0) break;
        }
        return;
    }

    function getCookieVal(offSet) {
        var endStr = document.cookie.indexOf(";", offSet);
        if (endStr == -1) {
            endStr = document.cookie.length;
        }
        return unescape(document.cookie.substring(offSet, endStr));
    }

    // Assign values to cookie variable.
    function setCookie(name, value) {
        document.cookie = name + "=" + escape(value);
    }

    function getParameterByName(name) {
        name = name.replace(/[\[]/, "\\[").replace(/[\]]/, "\\]");
        var regex = new RegExp("[\\?&]" + name + "=([^&#]*)"),
            results = regex.exec(location.search);
        return results === null ? "" : decodeURIComponent(results[1].replace(/\+/g, " "));
    }

    $(document).ready(function () {
        if (getParameterByName('s') == 'ex') {
            OpenDialogForSessionExpired();
        }
    })
</script>

Answer 1

Please check Session_Start in global.asax.

Have you set Session.Timeout = x ?

Also for redirection, you can use:

Response.AppendHeader("Refresh", Convert.ToString(Session.Timeout * 60) + ";URL=Login.aspx");

in your main page Page_Load method.