Make ASP.NET bundling specify media=screen for CSS bundle

Unfortunately there isn't a great way to hook into how the tags are rendered currently, we thought about adding a hook so you could add your own method to render each script/style tag. It sounds like we do need to do that. Should be pretty simple to add, I'll create a work item to enable this scenario...

As a temporary workaround, if you are willing to lose the debug/release functionality that Styles.Render gives you, you can render a reference to the bundle using Styles.Url which would give you just the bundle url, you can embed that inside your own tag.

Another option to solve this issue, without compromising the debug ability, could be:

public static IHtmlString Render(string path, IDictionary<string, object> htmlAttributes)
{
    var attributes = BuildHtmlStringFrom(htmlAttributes);

#if DEBUG
    var originalHtml = Styles.Render(path).ToHtmlString();
    string tagsWithAttributes = originalHtml.Replace("/>", attributes + "/>");
    return MvcHtmlString.Create(tagsWithAttributes);
#endif

    string tagWithAttribute = string.Format(
        "<link rel=\"stylesheet\" href=\"{0}\" type=\"text/css\"{1} />", 
        Styles.Url(path), attributes);

    return MvcHtmlString.Create(tagWithAttribute);
}

What I'm doing is just appending the given html attributes to the end of the tags (on debug mode) or to the end of the only link tag (when minification/bundling are enabled).

The usage in views:

@Bundles.Render("~/css/print", new { media = "print" })

The rest of the code:

public static IHtmlString Render(string path, object htmlAttributes)
{
    return Render(path, new RouteValueDictionary(htmlAttributes));
}

private static string BuildHtmlStringFrom(IEnumerable<KeyValuePair<string, object>> htmlAttributes)
{
    var builder = new StringBuilder();

    foreach (var attribute in htmlAttributes)
    {
        builder.AppendFormat(" {0}=\"{1}\"", attribute.Key, attribute.Value);
    }

    return builder.ToString();
}

I've wrote a blog post about this subject: http://danielcorreia.net/blog/quick-start-to-mvc4-bundling/

Well, it's an ugly hack, but hopefully the team will add a built-in way to do it in the next release.

This is how I solved it, maintaining the caching string and still being able to add the media attribute to the tag.

@{
    var cssMediaBundleUrl = BundleTable.Bundles.ResolveBundleUrl("~/stylesheets/mediacss", true);
}
<link href="@cssMediaBundleUrl" rel="stylesheet" type="text/css" media="screen" />

Guess I can turn this into an Html helper, will do that later and edit.

I've found a more elegant solution.

I'm using the Styles.RenderFormat(format, bundle).

I have a BundlesFormats class with a property called PRINT and I use it like so:

public class BundlesFormats
{
    public const string PRINT = @"<link href=""{0}"" rel=""stylesheet"" type=""text/css"" media=""print"" />";
}

And in the cshtml:

@Styles.RenderFormat(BundlesFormats.PRINT, "~/bundles/Content/print")