title: Session State variables aren't working
body: <p>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.</p>
  
  <p>In my default page, I do this to create a Session variable:</p>
  
  <pre><code>Session.Add("UserData",userdata);
  </code></pre>
  
  <p>I have also tried this:</p>
  
  <pre><code>Session["UserData"] = userdata;
  </code></pre>
  
  <p>Then in a later page, I do this to try to call it:</p>
  
  <pre><code>object myobject = Session["UserData"];
  </code></pre>
  
  <p>This gives me an error, saying that <code>Session["UserData"]</code> is not set to an instance of an object. This is the method everyone seems to be using, is there something I'm missing?</p>
  
  <p>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:</p>
  
  <pre><code>&lt;sessionstate mode="inproc"/&gt;
  </code></pre>
  
  <p>EDIT, more detailed code:</p>
  
  <pre><code>MyClass userdata = new MyClass();
  userdata.name = "myname";
  userdata.number = 5;
  
  Session["UserData"] = userdata;
  </code></pre>
  
  <p>later...</p>
  
  <pre><code>MyClass mydata = (MyClass)(Session["UserData"]);
  </code></pre>
  
  <p>This returns the error that Session["UserData"] is null.</p>