User-474980206 posted
not clear what you are trying to do.
to get the parameters in OnActionExecuting
var args = context.ActionArguments;
each arg will have a name and value
to get the action result its in the OnActionExecuted:
var result = context.Result
typically if you are calling a view this will be of type IActionResult. From this you can get the ViewBag and the Model that will be passed to the view.