Update [2012-06-02]: Visual Studio 2012 RC includes a new bundle mechanism that supports chained transforms. Scott Hanselman posted an example that includes .less.
ASP.NET MVC 4 (beta) supports post-processed bundles which are especially useful for CSS style sheets and JavaScript. MVC 4 is shipped with minifiers for CSS and JavaScript, but you can also use your own post-processor. This is where you can plug in .less, using the dotlessClientOnly nuget package:
public class LessMinify : IBundleTransform
{
private readonly CssMinify _cssMinify = new CssMinify();
public void Process(BundleContext context, BundleResponse response)
{
if (context == null)
throw new ArgumentNullException("context");
if (response == null)
throw new ArgumentNullException("response");
response.Content = dotless.Core.Less.Parse(response.Content);
_cssMinify.Process(context, response);
}
}
Now you can create bundles with your own minifier:
var styles = new Bundle("~/Content/myStyle", new LessMinify());
styles.AddFile("~/Content/someStyle.less");
BundleTable.Bundles.Add(styles);