public MapTOCContentType CurrentMapTOCContent {get;}

{

  //Get the current active TOC content type for the map view 
  var mapTOCContentType = MapView.Active.CurrentMapTOCContent;

}

{

  //Get the current active TOC content type for the map view 
  var mapTOCContentType = (int)MapView.Active.CurrentMapTOCContent;
  //increment to the next tab whatever it is
  mapTOCContentType++;
  //Can we set this type on the TOC?
  if (MapView.Active.CanSetMapTOCContent((MapTOCContentType)mapTOCContentType))
    //Set it - must be on the UI! - No QueuedTask
    MapView.Active.SetMapTOCContentAsync((MapTOCContentType)mapTOCContentType);
  else
  {
    mapTOCContentType = (int)MapTOCContentType.DrawingOrder;
    //Set it - must be on the UI! - No QueuedTask
    MapView.Active.SetMapTOCContentAsync((MapTOCContentType)mapTOCContentType);
  }
}