ASP.Net’s [Authorize] attribute is another cool feature that makes it easy to add authentication at the Controller level when building a website, but the real goldmine here is that like nearly everything else in ASP.Net MVC, you can pick apart the functionality and extend it yourself – In this post we will take a look at creating our own custom Authentication attribute.

Anyone who asks me will know that i love the simplicity and elegance of creating ASP.Net MVC’s custom data annotations when writing your own validation in ASP.Net MVC. One situation that can be a tricky one to dig yourself out of when coming to more advanced validation logic is writing custom validation attributes that can see/compare properties between itself and other model properties.

Some people love them, others absolutely hate them, but if you ask me one of the coolest features in ASP.Net MVC is the Data Annotations that you use to decorate your ASP.Net MVC classes for validation. But one of the coolest things that came along in .Net 4.0 was support for this across the whole framework – even outside of ASP.Net MVC!