CAD恢复被删除的实体

     /// <summary>
    /// 删除实体、恢复被删除的实体
    /// </summary>
    /// <param name="dwg">当前文档</param>
    /// <param name="entIds">删除/恢复的实体</param>
    /// <param name="erasing">true：删除，false：恢复被删除的实体</param>
    public static void EraseEntities(Document dwg, ObjectIdCollection entIds, bool erasing)
    {
        using (var tran = dwg.TransactionManager.StartTransaction())
        {
            foreach (ObjectId id in entIds)
            {
                Entity ent;
                if (erasing)
                {
                    if (!id.IsErased)
                    {
                        ent = (Entity)tran.GetObject(id, OpenMode.ForWrite);
                        ent.Erase();
                    }
                }
                else
                {
                    if (id.IsErased)
                    {
                        ent = (Entity)tran.GetObject(id, OpenMode.ForWrite, true);
                        ent.Erase(false);
                    }
                }
            }
            tran.Commit();
        }
    }