Passing Session variable into c#

Posted on 2011-03-23
Last Modified: 2013-12-17

I'm not very familiar with c# but I'm trying to pass a session variable into a c# page abd having problem,

I'm guessing it's something with the private code block

the variable sets in login

 Context.Session("aspnetforumUserNickName") = "Administrator"

and when I try to load the c# page I  get this error

Object reference not set to an instance of an object.
Description: An unhandled exception occurred during the execution of the current web request. Please review the stack trace for more information about the error and where it originated in the code.

Exception Details: System.NullReferenceException: Object reference not set to an instance of an object.

Source Error:

Line 112:                        {
Line 113:                            //username = Session["aspnetforumUserName"].ToString();
Line 114:                            username = Session["aspnetforumUserNickName"].ToString();
Line 115:
Line 116:                        }

any help would be appreciated

protected void Page_PreRender(object sender, EventArgs e)
            cmd.Connection = cn;

            //if (lblVersion != null)
             //   string dllversion = System.Reflection.Assembly.GetExecutingAssembly().GetName().Version.ToString();
            //    lblVersion.Text = dllversion;

            bool integratedAuthEnabled = Utils.Settings.IntegratedAuthentication;
            //bool isForumPage = (Page is ForumPage);

            if (isForumPage)
                if (CurrentUserID == 0) //not logged in
                    //if (registerLink != null) registerLink.Visible = !integratedAuthEnabled;
                    if (logoutLink != null) logoutLink.Visible = false;
                    if (viewProfileLink != null) viewProfileLink.Visible = false;
                    if (loginTable != null) loginTable.Visible = !integratedAuthEnabled && ShowLoginTable;
                    if (curuserTable != null) curuserTable.Visible = false;
                    if (usersLink != null) usersLink.Visible = false;
                    if (aOpenId != null) aOpenId.Visible = Utils.Settings.EnableOpenId;
                else //logged in
                    //if (registerLink != null) registerLink.Visible = false;
                    //if (logoutLink != null) logoutLink.Visible = !integratedAuthEnabled;
                    if (loginTable != null) loginTable.Visible = false;
                    if (curuserTable != null) curuserTable.Visible = ShowLoginTable;
                    if (usersLink != null) usersLink.Visible = true;
                    //if (editProfileHeaderLink != null) editProfileHeaderLink.Visible = true;

                    if (viewProfileLink != null)
                        viewProfileLink.Visible = true;
                        string username;
                        //IF "integrated auth" is enabled
                        //AND it is windows-authenctication
                        //then lets remove tha domain name from "domain\user" username
                        if (Page.User is System.Security.Principal.WindowsPrincipal
                            && Utils.Settings.IntegratedAuthentication)
                            username = Session["aspnetforumUserName"].ToString();
                            username = username.Substring(username.IndexOf("\\") + 1);
                            //username = Session["aspnetforumUserName"].ToString();
                            username = Session["aspnetforumUserNickName"].ToString();

                        viewProfileLink.InnerHtml = username;

                    int unreadPrivateMsgs = GetUnreadPersonalMessagesCount();
                    string avatarPath = GetCurrUserAvatarImagePath();

                    if (imgAvatar != null) imgAvatar.Src = avatarPath;
                    if (spanNumMsgs != null)
                        spanNumMsgs.InnerHtml = unreadPrivateMsgs.ToString();
                        if (unreadPrivateMsgs > 0) spanNumMsgs.Style["font-weight"] = "bold";
                    if (spanNumUnreadThreads != null)
                        int updatedTopics = GetUpdatedThreadCount();
                        if (updatedTopics > 0)
                            spanNumUnreadThreads.InnerHtml = "(" + updatedTopics + ")";

            adminLink.Visible = isForumPage && IsAdministrator && adminLink != null;
            moderLink.Visible = isForumPage && IsModerator && moderLink != null;

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Question by:TheWebGuy38
  • 4
  • 3
LVL 39

Accepted Solution

Pratima Pharande earned 500 total points
ID: 35196356
check the condition like this

if ( Session["aspnetforumUserNickName"] !=  null )
                                                       username = Session["aspnetforumUserNickName"].ToString();

if its null means session isnot set properly                                       }
LVL 39

Expert Comment

by:Pratima Pharande
ID: 35196370
Insert the data to session like this

Session["aspnetforumUserNickName"] = "Administrator"

Author Comment

ID: 35196527
this is my vb code setting the session. I'm pretty sure it's correct

 Context.Session("aspnetforumUserID") = AspnetforumUserID
                        Context.Session("aspnetforumUserName") = Dr("UserName")
                        Context.Session("aspnetforumUserNickName") = "Administrator"

is there an issue going from vb to c?
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Author Comment

ID: 35196546
Very strange.

I added this like you said

         username = Session["aspnetforumUserNickName"].ToString();
                            if ( Session["aspnetforumUserNickName"] !=  null )
                                                      username = Session["aspnetforumUserNickName"].ToString();

and it passed the variable
LVL 33

Expert Comment

by:Todd Gerbert
ID: 35198198
How do your VB code and C# code relate to each other...i.e. is the VB code an HttpHandler, and the C# code the website - or do you have two different websites?

I'm also pretty sure your VB code is correct, but I'm also pretty sure checking for null before attempting to read the session variable has no effect on the exception you've cited. Which means either A) It was always working (and was just a rare condition/glitch that threw the exception in the first place) or B) It's not working now (and your test worked because, perhaps, of a condition unique to the debugging environment).
LVL 39

Expert Comment

by:Pratima Pharande
ID: 35204641
ok your Vb cod is right ?

is this are two differnt applications then I don't think you can share session like this

you can try to store the Session object in the database, that's easy to pass the Session object to other application

Author Comment

ID: 35204657
It seems to be working now.

I coded my site in .vb, but then I purchased a forum app that I integrated into the site that is c#
I know, a little messy, but it works
LVL 39

Expert Comment

by:Pratima Pharande
ID: 35204664
ok thats good

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