public ReadOnlyObservableCollection<Bookmark> GetBookmarks()

//Set the extent of a map frame to a bookmark.

//Perform on the worker thread
await QueuedTask.Run(() =>
{
  //Reference MapFrame
  MapFrame mf_bk = layout.FindElement("Map Frame") as MapFrame;

  //Reference a bookmark that belongs to a map associated with the map frame
  Map m = mf_bk.Map;
  Bookmark bk = m.GetBookmarks().FirstOrDefault(item => item.Name.Equals("Lakes"));

  //Set the map frame extent using the bookmark
  mf_bk.SetCamera(bk);
});

//Create a map frame and set its camera by zooming to the extent of an existing bookmark.

//Construct on the worker thread
await QueuedTask.Run(() =>
{
  //Build 2D envelope geometry
  Coordinate2D mf_ll = new Coordinate2D(6.0, 8.5);
  Coordinate2D mf_ur = new Coordinate2D(8.0, 10.5);
  //At 2.x - Envelope mf_env = EnvelopeBuilder.CreateEnvelope(mf_ll, mf_ur);
  Envelope mf_env = EnvelopeBuilderEx.CreateEnvelope(mf_ll, mf_ur);

  //Reference map, create MF and add to layout
  MapProjectItem mapPrjItem = Project.Current.GetItems<MapProjectItem>()
                       .FirstOrDefault(item => item.Name.Equals("Map"));
  Map mfMap = mapPrjItem.GetMap();
  Bookmark bookmark = mfMap.GetBookmarks().FirstOrDefault(
                        b => b.Name == "Great Lakes");

  //At 2.x - MapFrame mfElm =
  //                  LayoutElementFactory.Instance.CreateMapFrame(
  //                                             layout, mf_env, mfMap);
  //         mfElm.SetName("New Map Frame");
  //
  MapFrame mfElm = ElementFactory.Instance.CreateMapFrameElement(
                       layout, mf_env, mfMap, "New Map Frame");

  //Zoom to bookmark
  mfElm.SetCamera(bookmark);
});

public Task<bool> ZoomToBookmark(string bookmarkName)
{
  return QueuedTask.Run(() =>
  {
    //Get the active map view.
    var mapView = MapView.Active;
    if (mapView == null)
      return false;

    //Get the first bookmark with the given name.
    var bookmark = mapView.Map.GetBookmarks().FirstOrDefault(b => b.Name == bookmarkName);
    if (bookmark == null)
      return false;

    //Zoom the view to the bookmark.
    return mapView.ZoomTo(bookmark);
  });
}

public async Task<bool> ZoomToBookmarkAsync(string bookmarkName)
{
  //Get the active map view.
  var mapView = MapView.Active;
  if (mapView == null)
    return false;

  //Get the first bookmark with the given name.
  var bookmark = await QueuedTask.Run(() => mapView.Map.GetBookmarks().FirstOrDefault(b => b.Name == bookmarkName));
  if (bookmark == null)
    return false;

  //Zoom the view to the bookmark.
  return await mapView.ZoomToAsync(bookmark, TimeSpan.FromSeconds(2));
}

public Task<ReadOnlyObservableCollection<Bookmark>> GetProjectBookmarksAsync()
{
  //Get the collection of bookmarks for the project.
  return QueuedTask.Run(() => Project.Current.GetBookmarks());
}

public Task<ReadOnlyObservableCollection<Bookmark>> GetActiveMapBookmarksAsync()
{
  return QueuedTask.Run(() =>
  {
    //Get the active map view.
    var mapView = MapView.Active;
    if (mapView == null)
      return null;

    //Return the collection of bookmarks for the map.
    return mapView.Map.GetBookmarks();
  });
}

public Task RemoveBookmarkAsync(Map map, string name)
{
  return QueuedTask.Run(() =>
  {
    //Find the first bookmark with the name
    var bookmark = map.GetBookmarks().FirstOrDefault(b => b.Name == name);
    if (bookmark == null)
      return;

    //Remove the bookmark
    map.RemoveBookmark(bookmark);
  });
}