title: How do I set a "Default Action" for my Controller that will be called when no other action matches?
body: <p>Say I have the following route:</p>
  
  <pre><code>routes.MapRoute("Default", "{controller}/{action}/{id}", 
      new { controller = "Home", action = "Index", id = "" });
  </code></pre>
  
  <p>Lets also say that my controller has the following methods: <code>Index(Int32 id)</code> and <code>Edit(Int32 id)</code>.</p>
  
  <p>So <code>/MyController/Index/1</code> is a valid URL for that route.  So is <code>/MyController/Edit/1</code></p>
  
  <p>However, if a URL is received that correctly maps to my controller but not to an existing action, how do I define a "Default Action" to execute instead of letting the MVC framework throw up an error screen?</p>
  
  <p>Basically I'd like the URLs <code>/MyController/Preview/1</code> and <code>/MyController/Whatever/1</code> to execute an action that I specify ahead of time when the {action} token can't be mapped to an existing action on my controller.</p>
  
  <p>I see that the MvcContrib project on Codeplex has an attribute that enables this for use with the ConventionController, but I'd like to keep this with pure MS ASP.NET MVC for now.</p>
  
  <p>I also see that <a href="http://fredrik.nsquared2.com/viewpost.aspx?PostID=460" rel="noreferrer">Fredrik</a> mentions a <code>[ControllerAction(DefaultAction = true)]</code> attribute, but I can't find mention of it anywhere except his blog (and my app won't compile when I try it in my controller).</p>