[MSCE C#] 获取元素ec属性时DgnECInstanceCollection的count为0？

代码时仿照写的 ，如下

 FindInstancesScopeOption opt = new FindInstancesScopeOption(DgnECHostType.Element, true);
                    FindInstancesScope scope = FindInstancesScope.CreateScope(elm, opt);
                    DgnECConnectionOptions dgnECConOps = new DgnECConnectionOptions();
                    ECQuery query = new ECQuery();
                    query.SelectClause.SelectAllProperties = true;
                    DgnECInstanceCollection ecCollection = DgnECManager.Manager.FindInstances(scope, query);