GetWebResourceUrl generated WebResources.axd url is invalid

I made a few controls that loaded and included a resource js file. And it all worked well, until I wanted to load the js file from the Page object. The generated url was invalid. After hours of nervewrecking attempts I realised that the problem was I was using control.GetType() to get the type required as a parameter in GetWebResourceUrl. And the page, even if inheriting from a custom page object that resided in the assembly where the embedded resources were, was of the site assembly.

Solution: use GetWebResourceUrl(typeof(knownClassInTheAssembly),resourceName);

Warning: my object was inherited from Page and placed in the necessary assembly. And it still didn't work. It is good to remember that ASP.Net pages are not of the type they inherit from, but a class with the name of the page and that resides in the dynamically generated assembly of the site! So be careful where you use this.GetType()