Arcobjects 10.3.1: TOC listeners

Question

I am writting an addin using ArcObjects C#. I have setup the following listeners, but they are not being hit.

My code at the top of the addin.Extension class is:

...
private static IActiveViewEvents_ItemAddedEventHandler tocAddHandler;
private static IActiveViewEvents_ItemDeletedEventHandler tocDeleteHandler;
...


protected override void OnStartup()
{
     WireDocumentEvents();     
}
....
 private void WireDocumentEvents()
{
ArcMap.Events.OpenDocument +=
                new ESRI.ArcGIS.ArcMapUI.IDocumentEvents_OpenDocumentEventHandler(PostMxDLoad);

}
...
private void PostMxDLoad()
{
... some other stuff 

 tocDeleteHandler = new IActiveViewEvents_ItemDeletedEventHandler(SettingsMgr.TableofContents.OnTOCItemDeleted);
((IActiveViewEvents_Event)ArcMap.Document.FocusMap).ItemDeleted += tocDeleteHandler;

tocAddHandler = new IActiveViewEvents_ItemAddedEventHandler(SettingsMgr.TableofContents.OnTOCItemAdded);
((IActiveViewEvents_Event)ArcMap.Document.FocusMap).ItemAdded += tocAddHandler;
}

Answer 1

You should change your PostMxDLoad method like the following and also add another method, let's say OnActiveViewEventsItemDeleted to handle the event. Here's how:

private void PostMxDLoad()
{
    //... some other stuff 
    if (ArcMap.Document.FocusMap != null)
    {
        //you need to loop the following if there are other dataframes (maps) in your mxd document
        var activeViewEvents = (IActiveViewEvents_Event)ArcMap.Document.FocusMap;
        activeViewEvents.ItemDeleted += new ESRI.ArcGIS.Carto.IActiveViewEvents_ItemDeletedEventHandler(OnActiveViewEventsItemDeleted);
    }
}

private void OnActiveViewEventsItemDeleted(System.Object Item)
{
  // TODO: Add your code here
  System.Windows.Forms.MessageBox.Show("ItemDeleted"); 
}

You can do the same for ItemAdded event accordingly.

Answer 2

I'm not sure what you want to do exactly, but it looks like you want to receive an event when a layer is added to, or deleted from the map, right? Here's a sample:

private IActiveViewEvents_Event _avEvents;

private void SetupEventHandler() 
{
    var mxDoc = (IMxDocument)ArcMap.Application.Document;
    _avEvents = (IActiveViewEvents_Event)mxDoc.FocusMap;
    _avEvents.ItemAdded += ItemAdded;
    _avEvents.ItemDeleted += ItemDeleted;
}

private void ItemAdded(object item)
{
    System.Windows.Forms.MessageBox.Show("Added");
}

private void ItemDeleted(object item)
{
    System.Windows.Forms.MessageBox.Show("Deleted");
}