title: Angular2 : Call method/ngoninit when parameter of route changes
body: <p>Right now I'm making a kind of web shop, and on my home page I've a dropdown of category Let say parent cat A, and sub cats B and C.</p>
  
  <p>Cat A, B and C are all represented by 1 component, CatAComponent. When I go in the first time in one of those cats, my ngoninit gets called and the pages displays what it needs to display. </p>
  
  <p>When I want to click on another sub cat, I'm still on the same component, but only a param of the route changes ( e.g. I was on localhost:123/CatA/CatB, now I'm on localhost:123/CatA/CatC, only a parameter changed so the ngOnInit does not get called and my update method does not get called neither).</p>
  
  <p>Any way to go around this? I can't put a (click) method in my view file to reference the method, the menu for categories is in another viewcomponent.</p>
  
  <p>Can I call an NgOnInit when only a parameter has changed?</p>