public MapSeries MapSeries {get;}

//Report the event args when the map series properties have changed.

//At 2.x - ArcGIS.Desktop.Layouts.Events.MapSeriesEvent.Subscribe((args) =>
//{
//  System.Windows.MessageBox.Show("MapSeriesEvent:" +
//  Environment.NewLine +
//  "   arg CurrentPageName: " + args.CurrentPageName.ToString() +
//  Environment.NewLine +
//  "   arg CurrentlPageNumber: " + args.CurrentPageNumber.ToString() +
//  Environment.NewLine +
//  "   arg Layout: " + args.Layout.Name +
//  Environment.NewLine +
//  "   arg Type: " + args.Type.ToString());
//});

ArcGIS.Desktop.Layouts.Events.LayoutEvent.Subscribe((args) =>
{
  var layout = args.Layout;
  if (args.Hint == LayoutEventHint.MapSeriesRefreshed ||
    args.Hint == LayoutEventHint.MapSeriesPageChanged)
  {
    var ms = layout.MapSeries;
    System.Diagnostics.Debug.WriteLine($"LayoutEvent {args.Hint.ToString()}: {layout.Name}");
  }
});

//Return the page number that corresponds to the page name field for an index feature

Layout layout = LayoutView.Active.Layout;

//Perform on the worker thread
await QueuedTask.Run(() =>
{
  SpatialMapSeries SMS = layout.MapSeries as SpatialMapSeries;
  Row msRow = SMS.CurrentRow;
  System.Windows.MessageBox.Show(SMS.FindPageNumber(msRow.GetOriginalValue(msRow.FindField("NAME")).ToString()));
});

//Get and modify a map series CIM definition and set the changes back to the layout

//Perform on the worker thread
await QueuedTask.Run(() =>
{
  MapSeries MS = layout.MapSeries as MapSeries;
  CIMMapSeries CIM_MS = MS.GetDefinition();
  CIM_MS.Enabled = false;
  MS.SetDefinition(CIM_MS);
  layout.SetMapSeries(MS);
});

//Set the current page to match a specific page number

//Perform on the worker thread
await QueuedTask.Run(() =>
{
  MapSeries MS = layout.MapSeries as MapSeries;
  MS.SetCurrentPageNumber("IV");
});