mEvent = pAxMapControl.ActiveView.FocusMap as IActiveViewEvents_Event;
mEvent.ItemAdded += new IActiveViewEvents_ItemAddedEventHandler(Event_ItemAdded);
mEvent.ItemDeleted += new IActiveViewEvents_ItemDeletedEventHandler(Event_ItemDeleted);

private void Event_ItemAdded(object Item)
{
    if (Item is IFeatureLayer)
    {
        FeatureLayerAdded(Item as IFeatureLayer);
    }
    else if (Item is IRasterLayer)
    {
         RasterLayerAdded(Item as IRasterLayer);
    }
    else if (Item is ILasDatasetLayer)
    {
         LasLayerAdded(Item as ILasDatasetLayer);
    }
}