Conditionally disable ASP.NET MVC Controller

Answered here - Prevent ASP.NET Core discovering Controller in separate assembly

This approach doesn't need filters, and hides controller from swagger etc.

The easiest would probably be to implement a custom action filter:

http://www.asp.net/mvc/tutorials/older-versions/controllers-and-routing/understanding-action-filters-cs

You can also conditionally add a route that matches that controller that would result in a 404 being returned.