如何配置NHibernate的事件侦听器的更新和保存？ [英] How to configure NHIbernate event listeners for Update and Save?

问题描述

这是我刚才的问题如何NHibernate的实体实施LASTUPDATE <？ 。/ A>

Following on from my previous question How to implement LastUpdate in NHibernate Entities?.

我在我的数据库我的审计表两列：

I have two columns on my audited tables in my database:

1. 创建日期时间默认GETDATE（）不为空（该行的创建日期）

LASTUPDATE日期时间空（将datetime此行的最后更新）

lastUpdate datetime null (the datetime this row was last updated)

我要创建的更新NHibernate的唯一监听器，因为数据库引擎需要照顾的新记录的默认约束。我试图创建与此代码自定义监听器：

I want to create a listener for updates only in NHibernate, because the database engine takes care of new records with the default constraint. I tried to create a Custom listener with this code:

public class CustomUpdateEventListener : DefaultSaveOrUpdateEventListener
{
    protected override object PerformSaveOrUpdate(SaveOrUpdateEvent evt)
    {
        var entity = evt.Entity as IAuditableEntity;
        if (entity != null)
        {
            ProcessEntityBeforeUpdate(entity);
        }
        return base.PerformSaveOrUpdate(evt);
    }

    internal virtual void ProcessEntityBeforeUpdate(IAuditableEntity entity)
    {
        entity.UpdateDate = DateTime.Now;
    }
}

和其更新的伟大工程，但它也得到为保存运行事件（当我新行添加到数据库中）。我不希望它火的新行。我试图修改代码来听更新事件仅但我不能工作了。

and it works great for updates, but it also gets run for Save events (when I add new rows to the database). I don't want it to fire for new rows. I tried to change the code to listen to Update events only but I can't work it out.

我试图改变类从 DefaultUpdateEventListener 继承，但有没有 UpdateEvent （仅 SaveOrUpdate 事件或 PreUpdate 或 PostUpdate ）

I tried to change the class to inherit from DefaultUpdateEventListener but there's no UpdateEvent (only SaveOrUpdate events or PreUpdate or PostUpdate)

我不知道我是否应该使用 PreUpdate 事件，并让我的听众从 DefaultUpdateEventListener 继承后来我'不能确定我需要重写哪种方法。没有更新方法重写。

I'm wondering if I should use the PreUpdate event and making my listener inherit from DefaultUpdateEventListener but then I'm not sure which method I need to override. There is no Update method to override.

推荐答案

您可以让您的类实现IPreUpdateEventListener接口（及其OnPreUpdate方法）。然后通过配置类添加到会话中的事件listerners：

You could make your class implement the IPreUpdateEventListener interface (and its OnPreUpdate method). Then add your class to the session event listerners through the config:

NHibernate.Cfg.Configuration cfg = new NHibernate.Cfg.Configuration();
cfg.EventListeners.PreUpdateEventListeners = 
    new IPreUpdateEventListener[] {new YourEventListener()};
sessionFactory = cfg.BuildSessionFactory();

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