title: How to prevent execution of controller actions based on condition?
body: <p>I have a controller with many actions.
  I need to prevent execution of <strong>some</strong> actions based on this condition:</p>
  
  <pre><code>if (Session["MyObject"] == null) return RedirectToAction("Introduction");
  </code></pre>
  
  <p>It should redirect to a default Introduction action.</p>
  
  <p>I can put this condition in each action, but I would like to define this condition just in one place, like in controller's constructor maybe.</p>
  
  <p>Any ideas? Thank you.</p>