Hello

I think I can help you out but I have a few clarification questions before I provide the best answer to your problem:

* Is there a business need to do this in the [ActionFilter]?
* Have you tried creating an additional Action Method on your controller to handle this situation?

Based on the scenario described above it appears your best option is creating a action method or perhaps a web API method on your controller that returns JSON and then specify the route.

Please provide a little bit more detail about your problem and what you are trying to solve and I can provide a better answer and more recommendations

I misread your originally question, my mistake. I'm understanding what you are trying to do. (sorry about that)

The code you provided looks correct to me assuming you have everything else working. Depending where you are trying to navigate from there are a few different ways to solve this problem. I am going to make the assumption you are trying to perform a new actionresult from the razor.

Try:

'@Url.Action("Controller", "Action")?categoryId=4'

When accessing other controller methods you really should use the UrlHelper object because it will generate the correct route that will include the module instance ID so your route won't conflict with other modules on the page.

Hope this helps, if this doesn't make sense I can try clarifying more