C# - How To Implement Caching Of Static Files

I use a Masterpage (asp.net webforms) on my site and I woluld like to implement caching of some static files, like javascript, css etc.

I've tried adding the following to my page_load (in the masterpage) but when I use Fiddler the static files are still under "no-cache".

protected void Page_Load(object sender, EventArgs e)
{
// Set cache for 1 hour on all computers and servers.
// ... Proxies, browsers, and your server will cache it.
Response.Cache.SetCacheability(HttpCacheability.Public);
Response.Cache.SetMaxAge(new TimeSpan(1, 0, 0));
}

What am i doing wrong here?