public PresentationPage ActivePage {get;}

{
  // Note: we are on the UI thread!
  // A presentation view must be active
  if (PresentationView.Active == null)
    return;
  PresentationPage currentActivePage = activePresentationView.ActivePage;

  //check if the current page is a map page
  if (activePage is MapPresentationPage)
  {
    await activePresentationView.ActivateMapPageAsync();
  }

  //move to the QueuedTask to do something
  await QueuedTask.Run(() =>
  {
    // TODO
  });
}