BundleCollectionExtensions.cs

using System;
using System.Diagnostics;
using System.Linq;
using System.Web;
using System.Web.Optimization;

[DebuggerStepThrough]
public static class BundleCollectionExtensions
{
    public static void VerifyStyleBundles(this BundleCollection instance)
    {
        foreach (var bundle in instance.OfType<StyleBundle>())
        {
            var bundleVirtualDirectory = bundle.Path.Substring(0, bundle.Path.LastIndexOf(@"/"));
            foreach (var file in bundle.EnumerateFiles(new BundleContext(new EmptyHttpContext(), instance, "~")))
            {
                var fileVirtualDirectory = file.IncludedVirtualPath.Substring(
                    0,
                    file.IncludedVirtualPath.LastIndexOf(@"/"));
                if (fileVirtualDirectory != bundleVirtualDirectory)
                {
                    throw new InvalidOperationException(
                        string.Format(
                            "Bundle '{0}' includes a file in a different location: '{1}'.",
                            bundle.Path,
                            file.IncludedVirtualPath));
                }
            }
        }
    }

    private class EmptyHttpContext : HttpContextBase
    {
    }
}