/// <summary>
        /// 删除元素
        /// </summary>
        /// <param name="map"></param>
        /// <param name="tree"></param>
        /// <param name="cmd"></param>
        private void DeleteObject(MapImage map, MyTree tree, string[] cmd)
        {
            if (cmd.Length != 4)
            {
                return;
            }
            decimal  layerid    = GetId(cmd[2]);
            decimal  objectid   = GetId(cmd[3]);
            TreeNode layernode  = FindLayer(tree.Nodes[0], layerid);
            TreeNode objectnode = FindObject(layernode, layerid, objectid);

            if (objectnode == null)
            {
                return;
            }
            //取得当前图层
            VectorLayer layer = layernode.Tag as VectorLayer;

            //如果有当前选择区域,则从图层中删除
            if (map.NeedSave && layer.NeedSave)
            {
                MapDBClass.DeleteObject(map.Map.MapId, layerid, objectid, layer.Type);
            }
            ((GeometryProvider)layer.DataSource).Geometries.Remove(objectnode.Tag as Geometry);
            tree.Nodes.Remove(objectnode);
        }