/// <summary>
        /// 获取图层所在的最低一级组图层。
        /// </summary>
        /// <param name="map">地图对象。</param>
        /// <param name="layer">图层对象。</param>
        /// <returns>图层所在的组图层或者null</returns>
        public static IGroupLayer GetBelongGroupLayer(IMap map, ILayer layer)
        {
            IEnumLayer  mapGroupLayers = LayerUtil.GetMapGroupLayers(map, true);
            IGroupLayer groupLayer     = mapGroupLayers.Next() as IGroupLayer;

            if (groupLayer != null)
            {
                Predicate <ILayer> layerPredicate = currentLayer => currentLayer == layer;
                while (groupLayer != null)
                {
                    if (LayerUtil.GetLayerOfGroupLayer(groupLayer, layerPredicate, false) != null)
                    {
                        if (groupLayer != null)
                        {
                            return(groupLayer);
                        }
                    }
                    groupLayer = (mapGroupLayers.Next() as IGroupLayer);
                }
            }
            return(null);
        }