How to specify HTTP expiration header? (ASP.NET MVC+IIS)

I am already using output caching in my ASP.NET MVC application.

http://code.google.com/speed/page-speed/">Page speed tells me to specify HTTP cache expiration for css and images in the response header.

I know that the Response object contains some properties that control cache expiration. I know that these properties can be used to control HTTP caching for response that I am serving from my code:

Response.Expires
Response.ExpiresAbsolute
Response.CacheControl

or alternatively

Response.AddHeader("Expires", "Thu, 01 Dec 1994 16:00:00 GMT");

The question is how do I set the Expires header for resources that are served automatically, e.g. images, css and such?

Found it:

I need to specify client cache for static content (in web.config).

<configuration>
  <system.webServer>
    <staticContent>
      <clientCache cacheControlCustom="public" 
      cacheControlMaxAge="12:00:00" cacheControlMode="UseMaxAge" />
    </staticContent>
   </system.webServer>
</configuration>

from http://www.iis.net/ConfigReference/system.webServer/staticContent/clientCache

If you want to do it from code for a resource that you're returning (ie. not a static file being served from IIS), you're better off using Response.Cache:

Response.Cache.SetExpires(DateTime.Now.AddYears(1));
Response.Cache.SetCacheability(HttpCacheability.Public);

I know that's not exactly what you're asking for, but I found this question via Google and figure others might like this answer as it's related to the APIs you show in the original question text.

Look at mini static content delivery project. :)