//获取块表
                BlockTable bt = (BlockTable)trans.GetObject(db.BlockTableId, OpenMode.ForRead);
                //获取图纸空间的块表记录
                BlockTableRecord btr = (BlockTableRecord)trans.GetObject(bt[BlockTableRecord.PaperSpace], OpenMode.ForRead);
                //在这些块表记录中进行循环
                foreach (ObjectId btrId in btr)
                {
                    if (btrId.GetBlockName() != null)
                    //取得块名
                    {
                        ed.WriteMessage("\n块名为：{0}", btrId.GetBlockName(), btrId.ToString());
                    }
                }