Determining when layer has been loaded in ArcObjects?

Question

Is there an event in ArcObjects to determine whether a layer (specifically a shapefile) has been loaded into a map?

I'm using ArcObjects 10.4.1 and C#

Answer 1

The event handler for capturing layers added to the map is IActiveViewEvents.ItemAdded

Make sure its pointing to a Map and not PageLayout.

You would then test to see if it is specifically a shapefile.

Answer 2

Here is some boiler plate code to set up active view events. You'll just need to write a function that checks if the item added is a shapefile. Call that function from Events_ItemAdded().

    public static IActiveViewEvents_Event ActiveViewEvent;    

    private void WireDocumentEvents()
    {
        // Event handlers
        ArcMap.Events.CloseDocument += new ESRI.ArcGIS.ArcMapUI.IDocumentEvents_CloseDocumentEventHandler(Events_CloseDocument);

        if (ActiveViewEvent == null)
            ActiveViewEvent = ArcMap.Document.FocusMap as IActiveViewEvents_Event;

        if (ActiveViewEvent == null) return;

        ActiveViewEvent.ItemAdded += Events_ItemAdded;
        ActiveViewEvent.ItemDeleted += Events_ItemRemoved;
    }

    private void UnWireDocumentEvents()
    {
        // Unload Event handlers
        ArcMap.Events.CloseDocument -= new ESRI.ArcGIS.ArcMapUI.IDocumentEvents_CloseDocumentEventHandler(Events_CloseDocument);

        if (ActiveViewEvent == null) return;

        ActiveViewEvent.ItemAdded -= Events_ItemAdded;
        ActiveViewEvent.ItemDeleted -= Events_ItemRemoved;

        ActiveViewEvent = null;
    }

    void Events_CloseDocument()
    {
        //DO SOMETHING WHEN DOCUMENT CLOSES
    }

    private void Events_ItemAdded(object item)
    {
       //DO SOMETHING WHEN ITEM ADDED
    }

    private void Events_ItemRemoved(object item)
    {
        //DO SOMETHING WHEN ITEM REMOVED
    }