title: How to add a WiX custom action that happens only on uninstall (via MSI)?
body: <p>I would like to modify an MSI installer (created through <a href="http://en.wikipedia.org/wiki/WiX" rel="noreferrer">WiX</a>) to delete an entire directory on uninstall.</p>
  
  <p>I understand the <code>RemoveFile</code> and <code>RemoveFolder</code> options in WiX, but these are not robust enough to recursively delete an entire folder that has content created after the installation.</p>
  
  <p>I noticed the similar Stack Overflow question <em><a href="https://stackoverflow.com/questions/195919">Removing files when uninstalling WiX</a></em>, but I was wondering if this could be done more simply using a call to a batch script to delete the folder.</p>
  
  <p>This is my first time using WiX, and I'm still getting the hang of <a href="http://wix.sourceforge.net/manual-wix2/authoring_custom_actions.htm" rel="noreferrer">custom actions</a>. What would be a basic example of a custom action that will run a batch script on uninstall?</p>