How to create the confirm box in mvc controller?

I need to create the confirm box in mvc controller?. Using this 'yes' or 'no' value I need to perform the action in my controller. How we do that?

Sample code:

    public ActionResult ActionName(passing value)
        {
             // some code 
             message box here
               if (true)
                     { true code}
              else { else code}
       }