As we all know you should never rely on client side validation and you should always validate input (especially user input) prior to calling any business methods or database calls. My problem has always been with trying to get the validation messages back to the client. I am always determined to have my validation routines in my business layer. But then comes time to report validation errors back to the client and I end up sticking them in the code behind. Sure I might (emphasis on might) create a utility or helper class but then the routines become more and more specific and less and less common and I am right back to sticking them in the code behind. Where else can you put them since you not only have access to the control but you also have all the tools you need to render the output? While I have been playing with MVC I have found myself once again struggling with sending validation messages back to the user. This time, however, I decided to try a few different techniques and one has proven to work well (for me at least).