public bool ZoomToSelectedElements( 
   Nullable<TimeSpan> duration
)

//Set the layout view extent to the selected elements.

//Process on worker thread
await QueuedTask.Run(() =>
{
  layoutView.ZoomToSelectedElements();
});

//This example references the active layout view.  Next it finds a couple of elements and adds them to a collection. 
//The elements in the collection are selected within the layout view.  Finally, the layout view is zoomed to the
//extent of the selection.

// Make sure the active pane is a layout view and then reference it
if (LayoutView.Active != null)
{
  LayoutView lytView = LayoutView.Active;
  //Reference the layout associated with the layout view
  Layout lyt = await QueuedTask.Run(() => lytView.Layout);

  //Find a couple of layout elements and add them to a collection
  Element map1 = lyt.FindElement("Map1 Map Frame");
  Element map2 = lyt.FindElement("Map2 Map Frame");
  List<Element> elmList = new List<Element>();
  elmList.Add(map1);
  elmList.Add(map2);

  //Set the selection on the layout view and zoom to the selected elements
  await QueuedTask.Run(() => lytView.SelectElements(elmList));
  await QueuedTask.Run(() => lytView.ZoomToSelectedElements());
}

// Make sure the active pane is a layout view and then reference it
if (LayoutView.Active != null)
{
  LayoutView lytView = LayoutView.Active;
  //Reference the layout associated with the layout view
  Layout lyt = await QueuedTask.Run(() => lytView.Layout);

  //Find a couple of layout elements and add them to a collection
  Element map1 = lyt.FindElement("Map1 Map Frame");
  Element map2 = lyt.FindElement("Map2 Map Frame");
  List<Element> elmList = new List<Element>();
  elmList.Add(map1);
  elmList.Add(map2);

  //Set the selection on the layout view and zoom to the selected elements
  await QueuedTask.Run(() => lytView.SelectElements(elmList));
  await QueuedTask.Run(() => lytView.ZoomToSelectedElements());
  return true;
}
return false;