扩展数据名 删除

       //将选中实体的指定扩展数据名删除 

        public void SetNoLinkWire()
        {
            short iColor = 2;
            Document doc = Application.DocumentManager.MdiActiveDocument;
            Database db = doc.Database;
            Editor ed = doc.Editor;
            Transaction tr = db.TransactionManager.StartTransaction();
            string regAppName = "WireData";

            using (tr)
            {
                SelectionSet sels = CAD.CADMgr.CADSSet.SelectsByAppName(ed, "请选择一条或多条线线", regAppName);
                ObjectId[] objIds = sels.GetObjectIds();
                foreach (ObjectId objId in objIds)
                {
                    BlockReference refObj = tr.GetObject(objId, OpenMode.ForWrite) as BlockReference;
                    TypedValue[] tv = new TypedValue[]{
                           new TypedValue(1001,regAppName)};
                    ResultBuffer rb = new ResultBuffer(tv);
                    CAD.CADMgr.CADXRecord.SetXData(db, objId, regAppName, rb);
                    CAD.CADMgr.CADEntity.ChangeRefColor(db, refObj as BlockReference, Color.FromColorIndex(ColorMethod.ByLayer, iColor));

                }
                tr.Commit();
            }
        }