ArcGIS Pro 3.4 API Reference Guide
ArcGIS.Desktop.Layouts.Events Namespace / ElementEvent Class
Members Example Version

ElementEvent Class
Occurs when an Element style is changed.
Object Model
ElementEvent ClassSubscriptionToken ClassSubscriptionToken Class
Syntax
Remarks
This event is specific to changes to an element's style. For listening to general changes to the element's properties, use ElementsUpdatedEvent instead. Reference ElementEventArgs to get a list of arguments.
Example
ElementEvent_MapFrameActivated_Deactivated
//Report the event args when a map frame is activated or deactivated.

//At 2.x - ArcGIS.Desktop.Layouts.Events.ActivateMapFrameEvent.Subscribe((args) =>
//{
//  System.Windows.MessageBox.Show("ActiveMapFrameEvent:" +
//  Environment.NewLine +
//  "   arg IsActivated: " + args.IsActivated.ToString() +
//  Environment.NewLine +
//  "   arg Layout: " + args.Layout.Name +
//  Environment.NewLine +
//  "   arg MapFrame: " + args.MapFrame.Name);
//});

ArcGIS.Desktop.Layouts.Events.ElementEvent.Subscribe((args) =>
{
  var mapFrameName = args.Elements[0].Name;
  if (args.Hint == ElementEventHint.MapFrameActivated)
  {
    System.Diagnostics.Debug.WriteLine($"ElementEventHint.MapFrameActivated: {mapFrameName}");
  }
  else if (args.Hint == ElementEventHint.MapFrameDeactivated)
  {
    System.Diagnostics.Debug.WriteLine($"ElementEventHint.MapFrameDeactivated: {mapFrameName}");
  }
});
ElementEvent_ElementAdded
//Report the event args when an element is added to the layout.

//At 2.x - 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);
//});

ArcGIS.Desktop.Layouts.Events.ElementEvent.Subscribe((args) =>
{
  string elemNames = "null";
  if (args.Elements?.Count() > 0)
  {
    elemNames = string.Join(",", args.Elements.Select(e => e.Name).ToList());
  }
  if (args.Hint == ElementEventHint.ElementAdded)
  {
    System.Diagnostics.Debug.WriteLine($"ElementEventHint.ElementAdded: {elemNames}");
  }
});
ElementEvent_ElementRemoved
//Report the event args when an element is removed from the layout.

//At 2.x - ArcGIS.Desktop.Layouts.Events.ElementRemovedEvent.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("ElementRemovedEvent:" +
//  Environment.NewLine +
//  "   arg Elements: " + elemNames.ToString() +
//  Environment.NewLine +
//  "   arg Layout: " + args.Layout.Name);
//});

ArcGIS.Desktop.Layouts.Events.ElementEvent.Subscribe((args) =>
{
  string elemNames = "null";
  if (args.Elements?.Count() > 0)
  {
    elemNames = string.Join(",", args.Elements.Select(e => e.Name).ToList());
  }
  if (args.Hint == ElementEventHint.ElementRemoved)
  {
    System.Diagnostics.Debug.WriteLine($"ElementEventHint.ElementRemoved: {elemNames}");
  }
});
ElementEvent_PlacementChanged
//Report the event args when an element's placement properties are changed.

//At 2.x - ArcGIS.Desktop.Layouts.Events.ElementsPlacementChangedEvent.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("ElementsPlacementChangedEvent:" +
//  Environment.NewLine +
//  "   arg Elements: " + elemNames.ToString() +
//  Environment.NewLine +
//  "   arg Layout: " + args.Layout.Name);
//});

ArcGIS.Desktop.Layouts.Events.ElementEvent.Subscribe((args) =>
{
  string elemNames = "null";
  if (args.Elements?.Count() > 0)
  {
    elemNames = string.Join(",", args.Elements.Select(e => e.Name).ToList());
  }
  if (args.Hint == ElementEventHint.PlacementChanged)
  {
    System.Diagnostics.Debug.WriteLine($"ElementEventHint.PlacementChanged: {elemNames}");
  }
});
ElementEvent_StyleChanged
//Report the event args when an element's style is changed.

//At 2.x - ArcGIS.Desktop.Layouts.Events.ElementStyleChangedEvent.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("ElementStyleChangedEvent:" +
//  Environment.NewLine +
//  "   arg Elements: " + elemNames.ToString() +
//  Environment.NewLine +
//  "   arg Layout: " + args.Layout.Name);
//});
ArcGIS.Desktop.Layouts.Events.ElementEvent.Subscribe((args) =>
{
  string elemNames = "null";
  if (args.Elements?.Count() > 0)
  {
    elemNames = string.Join(",", args.Elements.Select(e => e.Name).ToList());
  }
  if (args.Hint == ElementEventHint.StyleChanged)
  {
    System.Diagnostics.Debug.WriteLine($"ElementEventHint.StyleChanged: {elemNames}");
  }
});
ElementEvent_SelectionChanged
//Report the event args when a layout's selection has changed.

//At 2.x - ArcGIS.Desktop.Layouts.Events.LayoutSelectionChangedEvent.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("LayoutSelectionChangedEvent:" +
//  Environment.NewLine +
//  "   arg Elements: " + elemNames.ToString() +
//  Environment.NewLine +
//  "   arg Layout: " + args.Layout.Name);
//});

ArcGIS.Desktop.Layouts.Events.ElementEvent.Subscribe((args) =>
{
  if (args.Hint == ElementEventHint.SelectionChanged)
  {
    if (args.Container.GetSelectedElements()?.Count() > 0)
    {
      var elemNames = string.Join(",", args.Container.GetSelectedElements().Select(e => e.Name).ToList());
      System.Diagnostics.Debug.WriteLine($"ElementEventHint.SelectionChanged: {elemNames}");
    }
  }

});
ElementEvent_PropertyChanged
//Report the event args when an element has been updated.

//At 2.x - ArcGIS.Desktop.Layouts.Events.ElementsUpdatedEvent.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("ElementsUpdatedEvent:" +
//  Environment.NewLine +
//  "   arg Elements: " + elemNames.ToString() +
//  Environment.NewLine +
//  "   arg Layout: " + args.Layout.Name);
//});
ArcGIS.Desktop.Layouts.Events.ElementEvent.Subscribe((args) =>
{
  string elemNames = "null";
  //can be null if the name was changed
  if (args.Elements?.Count() > 0)
  {
    elemNames = string.Join(",", args.Elements.Select(e => e.Name).ToList());
  }
  else if (args.Container.GetSelectedElements()?.Count() > 0)
  {
    elemNames = string.Join(",", args.Container.GetSelectedElements().Select(e => e.Name).ToList());
  }

  if (args.Hint == ElementEventHint.PropertyChanged)
  {
    System.Diagnostics.Debug.WriteLine($"ElementEventHint.PropertyChanged: {elemNames}");
  }
});
Inheritance Hierarchy

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

Requirements

Target Platforms: Windows 11, Windows 10

ArcGIS Pro version: 3 or higher.
See Also