One of the many nice things they have added in MVC 2 is model/view model validation on both the client and server side. I won’t go into the basics here since they have been covered extensively by others. However, recently I was adding validation to require a value for a hidden field on a form, and found that the default validation functionality just didn’t work on the client side for a hidden field. Here I will go over how I added some custom validation to allow me to do it.
While it might sound weird to validate a hidden field, something a user will never directly interact with, in this age of complex interfaces built in JavaScript it’s easy to imagine a scenario where a series of interactions leads to storing some kind of value in a hidden field. If that end value is something that is required, it’s only natural that that should be enforced by the model.
