There is an unsaved comment in progress. You will lose your changes if you continue. Are you sure you want to reopen the work item?
Async support only works for Controllers that inherit from AsyncController
In the more recent versions of MVC, inheriting from AsyncController is no longer required (or suggested), and it's "provided for backward compatability with MVC3"
If you don't inherit from AsyncController however, you can't use T4MVC with Async action methods.