title: HttpContext.Current.Session is null in Ashx file
body: <p>I saw some questions (<a href="https://stackoverflow.com/questions/5868599/httpcontext-current-session-is-null">Here</a> and <a href="https://stackoverflow.com/questions/4710411/httpcontext-current-session-null-item">Here</a>) but they do not answer my question. 
  I am trying to call Ajax using "ajax.ashx" file, and in function to access Session.
  For some reason, the value of the Session object itself is null.</p>
  
  <p>Use example:</p>
  
  <pre><code>Session = HttpContext.Current.Session // This is null
  </code></pre>
  
  <p>Or:</p>
  
  <pre><code>public virtual void ProcessRequest(HttpContext context)
  {
      System.Web.SessionState.HttpSessionState Session = context.Session; 
      // This is null
  }
  </code></pre>
  
  <p>In the Web.config:</p>
  
  <pre class="lang-html prettyprint-override"><code>&lt;sessionState timeout="1800"&gt;&lt;/sessionState&gt;
  </code></pre>