A.D.D. In IT

Here is a reCAPTCHA control for ASP.NET MVC that uses ModelState. This code includes the ActionFilter as well as the HTML Helper for rendering the reCAPTCHA control.

In one web application that uses the popular Recaptcha control to prevent spam we were receiving a decent number of exceptions related to invalid parameters. The error was "Value cannot be null. Parameter name: Challenge". I'm going to explain this error and how to go about fixing it.