覆盖 DefaultDeleteEventListener 和 DefaultLoadEventListener 为使用 Nhibernate 实现软可删除提供了一个非常好的解决方案。
public class SoftDeletableLoadEventListener : DefaultLoadEventListener
{
#region Non-public members
protected override object DoLoad(LoadEvent @event,
IEntityPersister persister, EntityKey keyToLoad,
LoadType options)
{
object entity = base.DoLoad(@event, persister, keyToLoad, options);
var softEntity = entity as ISoftDeletable;
if (softEntity != null && softEntity.IsDeleted)
{
if (options == LoadEventListener.ImmediateLoad
|| options == LoadEventListener.Load)
{
string msg =
string.Format("Can not Load soft deleted entity typeof({0}) with Id {1} as it was deleted.",
softEntity.GetType().Name,
softEntity.Id);
throw new InvalidOperationException(msg);
}
}
return entity;
}
#endregion
}
正如 DefaultLoadEventListener 状态的摘要: 定义 NHibernate 用于加载实体以响应生成的加载事件的默认加载事件侦听器。
这意味着在执行 ExtraLazyLoading 时不应用过滤器,这会导致例如:已删除的实体被计数。是否有另一种方法可以在查询期间应用软可删除过滤器?有没有更好的方法,然后总是手动过滤添加限制?