Subscribe Method (ElementEvent)

In This Topic

Subscribe to the ElementEvent.

Syntax

C#
Visual Basic (Declaration)

public static SubscriptionToken Subscribe( 
   Action<ElementEventArgs> action,
   bool keepSubscriberAlive
)

Public Shared Function Subscribe( _
   ByVal action As Action(Of ElementEventArgs), _
   Optional ByVal keepSubscriberAlive As Boolean _
) As SubscriptionToken

Parameters

action: The delegate that gets executed when the event is published.
keepSubscriberAlive: When false the CompositePresentationEvent will maintain a weak delegate reference to the subscriber. Using a weak delegate reference relieves the subscriber from the need to unsubscribe to enable proper garbage collection. The default is false.

Return Value

A SubscriptionToken that uniquely identifies the added subscription.

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}");
  }
});

Requirements

Target Platforms: Windows 11, Windows 10

ArcGIS Pro version: 3 or higher.

Reference

ElementEvent Class
ElementEvent Members

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