ArcGIS Pro 2.7 API Reference Guide
ElementAddedEvent Class
Members  Example 

ArcGIS.Desktop.Layouts.Events Namespace : ElementAddedEvent Class
Occurs when one ore more Elements are added to the Layout.
Object Model
ElementAddedEvent ClassSubscriptionToken ClassSubscriptionToken Class
Syntax
Remarks
Reference ElementsUpdatedEventArgs to get a list of arguments.
Example
//Report the event args when an element is added to the layout.

ArcGIS.Desktop.Layouts.Events.ElementAddedEvent.Subscribe((args) => 
{
  var elements = args.Elements;
  string elemNames = "null";
  if (elements != null && elements.Count() > 0)
  {
    elemNames = string.Join(",", elements.Select(e => e.Name).ToList());
  }
  System.Windows.MessageBox.Show("ElementAddedEvent:" +
  Environment.NewLine +
  "   arg Elements: " + elemNames.ToString() +
  Environment.NewLine +
  "   arg Layout: " + args.Layout.Name);
});
Inheritance Hierarchy

System.Object
   ArcGIS.Core.Events.EventBase
      ArcGIS.Core.Events.CompositePresentationEvent<TPayload>
         ArcGIS.Desktop.Layouts.Events.ElementAddedEvent

Requirements

Target Platforms: Windows 10, Windows 8.1

See Also

Reference

ElementAddedEvent Members
ArcGIS.Desktop.Layouts.Events Namespace