public ActionResult AddSlide(int id, AddSlide model)
 {
     Playlist playlist = playlistService.GetPlaylistByID(id);
     List<Slide> slides = slideService.GetAllSlides().ToList();
     for (int i = 0; i < slides.Count; i++)
     {
         if (model.IsSelected[i])
         {
             playlistService.ConnectSlide(playlist.PlaylistID, slides[i].SlideID);
         }
     }
     return RedirectToAction("Edit", new { id = playlist.PlaylistID });
 }
 public ActionResult AddSlide(int id)
 {
     AddSlide model = new AddSlide();
     model.Slides = slideService.GetAllSlides().ToList();
     return View(model);
 }