The code to check if Session has expired-- C#.Net

I have Login.aspx page in my web-application. When the session expires (session timeout=15) the user will be redirected to the Login.aspx page.

The Orders.aspx page contains Logout link. When the user clicks the Logout link..the Login.aspx page shows up.

I need to create some logic to bring up a Modal window in the center of the screen After Login.aspx was displayed to the user..in other words

if the Login page was displayed to the User as result of SessionTimeout ..the modal window should be displayed in the middle of the screen;  this window will show a Message "Session has expired" to the User  and OK button to close this moda window. So there are Two Possible scenarios:


1) If the User hits Logout link..on the  Orders.aspx page...the Login.aspx page will be displayed; nothing else is required in such case.


2) If Session has Expired..the Login.aspx page will be displayed to User; after that a modal window (showing "Session has expired") pop-ups in the

middle of the screen; The user hits OK button to close this window.

There is a good info on the web showing how to create aspnet-session-timeout control. The url:

http://www.eggheadcafe.com/tutorials/asp-net/7262426f-3c65-4c90-b49c-106470f1d22a/build-an-aspnet-session-timeout-redirect-control.aspx


Can I use the below logic in my Login.aspx (from the above link) to develop the above functionality (#1 And #2)?? Is it OK to use onPrerender(..)  event?
 What can I change to improve this logic?


------ mY Logic in Login.aspx Page-----

 protected override void OnPreRender(EventArgs e)
        {
            // base.OnPreRender(e);

   
            if (Context.Session != null)
            {
                 if (Context.Session.IsNewSession)
                {
                    string sCookieHeader = Page.Request.Headers["Cookie"];
                     if ((null != sCookieHeader) && (sCookieHeader.IndexOf("ASP.NET_SessionId") >= 0))
                     {
                          if (Page.Request.IsAuthenticated)
                          {
                              // FormsAuthentication.SignOut();
                          }
                          // Page.Response.Redirect(this._redirectUrl);

                          lblLabel1.Text="Session has expired"; // later add code to display pop-up window instead of label lblLabel1
                    }
                }
            }
        }

------

The original code from web-site: It also allows to download a sample project.

namespace PAB.WebControls
{
    using System;
    using System.ComponentModel;
    using System.Web;
    using System.Web.Security;
    using System.Web.UI;
 
    [DefaultProperty("Text"),
        ToolboxData("<{0}:SessionTimeoutControl runat=server></{0}:SessionTimeoutControl>")]
    public class SessionTimeoutControl : Control
    {
         private string _redirectUrl;
 
        [Bindable(true),
            Category("Appearance"),
            DefaultValue("")]
        public string RedirectUrl
        {
            get { return _redirectUrl; }
 
            set { _redirectUrl = value; }
        }
 
 
        public override bool Visible
        {
            get { return true; }
 
 
        }
 
 
        public override bool EnableViewState
        {
            get { return false; }
        }
 
 
        protected override void Render(HtmlTextWriter writer)
        {
            if (HttpContext.Current == null)
                 writer.Write("[ *** SessionTimeout: " + this.ID + " *** ]");
            base.Render(writer);
        }
 
 
        protected override void OnPreRender(EventArgs e)
        {
            base.OnPreRender(e);
             if (this._redirectUrl == null)
                throw new InvalidOperationException("RedirectUrl Property Not Set.");
            if (Context.Session != null)
            {
                 if (Context.Session.IsNewSession)
                {
                    string sCookieHeader = Page.Request.Headers["Cookie"];
                     if ((null != sCookieHeader) && (sCookieHeader.IndexOf("ASP.NET_SessionId") >= 0))
                     {
                          if (Page.Request.IsAuthenticated)
                          {
                              FormsAuthentication.SignOut();
                         }
                          Page.Response.Redirect(this._redirectUrl);
                    }
                }
            }
        }
    }
}

Thanks
niceguy971Asked:
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gery128Commented:
modify your code like this:

if (Page.Request.IsAuthenticated)
                          {
                              // FormsAuthentication.SignOut();
                             Page.Response.Redirect(this._redirectUrl+"?SessionExpired=true);
                          }
                          Page.Response.Redirect(this._redirectUrl);

Open in new window

and on Login page's page_prerender you check for SessionExpried variable in querystring and display message or modal window.

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niceguy971Author Commented:
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