Question

I’m writing an ASP.NET C# web site that needs to access data from a database and show it to the user for viewing and editing. The specific data it accesses is based on the user who logs in, and I need for multiple users to be able to use the site simultaneously, viewing and editing different data as they do so. I stumbled upon the concept of Session States, and after a lot of reading and not as much understanding. I’ve come across a problem.

In my default page, I do this to create a Session variable:

Session.Add("UserData",userdata);

I have also tried this:

Session["UserData"] = userdata;

Then in a later page, I do this to try to call it:

object myobject = Session["UserData"];

This gives me an error, saying that Session["UserData"] is not set to an instance of an object. This is the method everyone seems to be using, is there something I’m missing?

My site is configured on IIS to have the Session State Mode set to “In Process”, but most people seem to set this manually using their web.config file. However, when I try to do this in my web.config file I am always greeted with “unrecognized configuration section”. My compiler doesn’t know what this is:

<sessionstate mode="inproc"/>

EDIT, more detailed code:

MyClass userdata = new MyClass();
userdata.name = "myname";
userdata.number = 5;

Session["UserData"] = userdata;

later…

MyClass mydata = (MyClass)(Session["UserData"]);

This returns the error that Session[“UserData”] is null.

Answer 1

The fact that you can’t set the session mode in the web.config is a red flag to me of something weird and smelly going on. So …

1. Check that the session mode is under the system.web element of the web.config otherwise it won’t be valid.

2. Check that enableSessionState hasn’t been set to false in either the web.config or the page directive

3. Try to rule out IIS. If possible convert your website to a web app and run through visual studio so it starts with it’s own built in web server. What happens then? Is the Session state back?

4. It should n’t make a difference but if you are not doing the test in Page_Load then just try it there – just in case you are doing these tests somewhere unusual.

Whatever the answer is to this when we know it will be headachingly obvious. I’m geninuely looking forward to finding out what it is. Good luck