arx .net 中如何遍历被删除的图形？

sanmak

                BlockTable bt = (BlockTable)trans.GetObject(db.BlockTableId, OpenMode.ForRead);
                BlockTableRecord btr = (BlockTableRecord)trans.GetObject(bt[BlockTableRecord.ModelSpace], OpenMode.ForRead,true);
                foreach(ObjectId id in btr)
                {
                    Entity ent = trans.GetObject(id, OpenMode.ForWrite, true) as Entity;
                   
                    if (ent == null)
                        continue;

                }

                btr.Dispose();
            }
            catch(Exception e)
            {
            }
            finally
            {
                trans.Dispose();
            }

本想在此段代码中能遍历当前图形中所有的实体（包括已被删除的实体）。但被删除的实体无法找到。

请高手指点。