Warning in Session_End()

[anithaapr05]

After the session end i try to write the session value.In this, it write the session value after the session end, but i got the warning in application event.

My asp code:

void Session_End(object sender, EventArgs e)
    {
        // Code that runs when a session ends. 
 
        // Note: The Session_End event is raised only when the sessionstate mode
        // is set to InProc in the Web.config file. If session mode is set to StateServer
        // or SQLServer, the event is not raised.        
 
        string domainName = AppDomain.CurrentDomain.BaseDirectory.ToString();
        string strDirName = domainName.Replace("bin\\Debug\\", "");
 
        string enableLogging = ConfigurationSettings.AppSettings.Get("EnableSessionLog");
 
        if (enableLogging.ToLower() == "true")
        {
 
            TextWriter tw = new StreamWriter(strDirName + "Log Files\\SessionLog.txt", true);
            if (Session["portalID"] != null)
            {
                tw.WriteLine("Session Ends");
                tw.WriteLine(DateTime.Now + "  SessionTimedout SessionID = " + Session.SessionID);
                tw.WriteLine(DateTime.Now + "  SessionTimedout UserName = " + Session["session_username"].ToString());
                tw.WriteLine(DateTime.Now + "  SessionTimedout PortalID = " + Session["portalID"].ToString());
                tw.WriteLine(DateTime.Now + "  SessionTimedout PatientID = " + Session["patientID"].ToString());
            }
            tw.Close();
 
        }
    }    

My Warning is:

Event code: 3005
Event message: An unhandled exception has occurred.
Event time: 8/20/2009 11:19:24 AM
Event time (UTC): 8/20/2009 5:49:24 AM
Event ID: 7d1169968dd9490 2bc75c75234933e 12
Event sequence: 968
Event occurrence: 1
Event detail code: 0

Application information:
Application domain: b42109ff-1-128952191043738 926
Trust level: Full
Application Virtual Path: /ApplicationName
Application Path: C:\ApplicationN ame\
Machine name: MachineName

Process information:
Process ID: 3576
Process name: WebDev.WebServe r.EXE
Account name: MachineName\Adm inistrator

Exception information:
Exception type: NullReferenceEx ception
Exception message: Object reference not set to an instance of an object.

Request information:
Request URL:
Request path:
User host address:
User:
Is authenticated: False
Authentication Type:
Thread account name: MachineName\Adm inistrator

Thread information:
Thread ID: 10
Thread account name: MachineName\Adm inistrator
Is impersonating: False
Stack trace: at ASP.global_asax .Session_End(Ob ject sender, EventArgs e) in c:\ApplicationN ame\Global.asax :line 80

I got the warning in this line- tw.WriteLine(Da teTime.Now + " SessionTimedout UserName = " + Session["session_userna me"].ToString());

After session end i tried to write the session value.Please any one tell me how to avoid this

[Frinavale]

@anithaapr05
Always check to see if the values in session are null before trying to use them. It seems that you are attempting to access Objects that no longer exist. First check if they exist, and if they do exist then use them. Don't ever assume that they exist...

It should look something like:

   if (enableLogging.ToLower() == "true")
   {
 
            TextWriter tw = new StreamWriter(strDirName + "Log Files\\SessionLog.txt", true);
            if (Session["portalID"] != null)
            {
                tw.WriteLine("Session Ends");
                if(Session != null){
                  If(Session.SessionID != null){
                    tw.WriteLine(DateTime.Now + "  SessionTimedout SessionID = " + Session.SessionID);
                  }
                 }
                If(Session["session_username] != null){
                  tw.WriteLine(DateTime.Now + "  SessionTimedout UserName = " + Session["session_username"].ToString());
                }
                if(Session["portalID"] != null){
                  tw.WriteLine(DateTime.Now + "  SessionTimedout PortalID = " + Session["portalID"].ToString());
                }
                if(Session["patientID"] != null){
                  tw.WriteLine(DateTime.Now + "  SessionTimedout PatientID = " + Session["patientID"].ToString());
                }
            }
            tw.Close();
    }