public enum PresentationTransitionType : System.Enum, System.IComparable, System.IConvertible, System.IFormattable, System.ISpanFormattable  

{
  // create customized margin and color 
  CIMMargin pMargin = new CIMMargin() { Left = 0.2, Right = 0.3, Top = 0.15, Bottom = 0.25 };
  CIMRGBColor pColor = new CIMRGBColor() { R = 255, G = 255, B = 0, Alpha = 50 };

  //Reference a page and its transition 
  var pageReference = activePresentationView.Presentation.GetPage(0);
  CIMPresentationTransition transition = page.Transition;

  // update the transition style
  transition.TransitionType = PresentationTransitionType.Swipe;
  transition.Duration = 2.0;
  transition.SwipeDirection = SwipeDirection.Top;

  //Must be on the QueuedTask

  //Set the new margin, new background color and new transition effect
  page.SetMargin(pMargin);
  page.SetBackgroundColor(pColor);
  page.SetTransition(transition);
}