title: How long does a session[] retain data?
body: <p>I am trying to use a session but when i need the value back its null?</p>
  
  <p>My website starts off with a login where i put the user name into a Session.</p>
  
  <pre><code>Session["userName"] = login.UserName;
  </code></pre>
  
  <p>Then the website is redirected to a new page.</p>
  
  <pre><code>return RedirectToAction("Choice", new { token = token });
  </code></pre>
  
  <p>after witch i use a link to move to my next page.</p>
  
  <pre><code>@Html.ActionLink("Download", "Download", new {token = Model.Token})
  </code></pre>
  
  <p>Where i direct my code to a action result in the Home controller, the same controller i have my login function.</p>
  
  <pre><code>@Html.ActionLink("Download", "DownloadFile", new { fileid = item.Key, token = Model.Token, platform = "windows", filename = item.Value }, new {@class = "DownloadLink" } )
  </code></pre>
  
  <p>Where i try call up my session value again.</p>
  
  <pre><code>formMobiApi.GetFile(token, fileid, platform, filename, Session["userName"].ToString(), tasks, taskId, spreadSheetStatus);
  </code></pre>
  
  <p>Are any of these actions doing anything to make my session value null?</p>
  
  <p>Can i use a session like this?</p>