arcengine开发如何遍历MapControl和PageLaoutControl中的图层，获取图层名称

  for (int i = 0; i < axMapControl1.Map.LayerCount; i++)
   {
         String layerName = axMapControl1.Map.get_Layer(i).Name;
         ComboBox.Items.Add(layerName);
    }

 for (int i = 0; i < axPageLayoutControl1.ActiveView.FocusMap.LayerCount; i++)
  {
        String layerName = axPageLayoutControl1.ActiveView.FocusMap.get_Layer(i).Name;
        ComboBox.Items.Add(layerName);
  }