In BeginExecuteCore i want to get the Action that will be called

I've create a base-controller and I'm trying to acquire in its BeginExecuteCore the action method that is associated.

Basically I need to check if an action/method has a [ChildActionOnly] Attribute. I know that I could use:

RouteData.Values["action"] as string

but this will cause issues in case there are actions with the same name (i.e. get,post), it will throw this exception when calling reflection based on a method name:

System.Reflection.AmbiguousMatchException

Thus, how can I implement a method to be called in BeginExecuteCore to check if the action has a specific attribute? This is how I would like to call the method (_IsActionChildActionOnly), I need Its implementation:

protected override IAsyncResult BeginExecuteCore(AsyncCallback callback, object state)
{
   if(_IsActionChildActionOnly() == true) //<---function call
   {
     //... do other stuff
   }

   return base.BeginExecuteCore(callback, state);
}

private bool _IsActionChildActionOnly()
{
  //How can implement this method?...
  //Check if action has attribute...
}

If what I'm trying to achieve is not possible or my approach is wrong, please let me know if there are any other solutions.