我们通过使用NH的事件监听器来做到这一点(这不是我的工作,但我找不到我做这件事的链接…)。
我们有一个EventListener,用于在读取数据时将其设置为ReadOnly,然后有一个用于Save(和SaveOrUpdate),用于将它们设置为已加载,因此当我们手动调用Save()
时,该对象将持久存在。
也可以使用没有状态/更改跟踪的IStatelessSession。
这会在加载时立即将实体/项设置为ReadOnly。
我只包含了一个Insertion事件侦听器,但我的配置代码引用了所有这些侦听器
/// <summary>
/// A listener that once an object is loaded will change it s status to ReadOnly so that
/// it will not be automatically saved by NH
/// </summary>
/// <remarks>
/// For this object to then be saved, the SaveUpdateEventListener is to be used.
/// </remarks>
public class PostLoadEventListener : IPostLoadEventListener
{
public void OnPostLoad(PostLoadEvent @event)
{
EntityEntry entry = @event.Session.PersistenceContext.GetEntry(@event.Entity);
entry.BackSetStatus(Status.ReadOnly);
}
}
在保存对象时,我们调用它将该对象设置为Loaded(这意味着它现在将持久存在)
public class SaveUpdateEventListener : ISaveOrUpdateEventListener
{
public static readonly CascadingAction ResetReadOnly = new ResetReadOnlyCascadeAction();
/// <summary>
/// Changes the status of any loaded item to ReadOnly.
/// </summary>
/// <remarks>
/// Changes the status of all loaded entities, so that NH will no longer TrackChanges on them.
/// </remarks>
public void OnSaveOrUpdate(SaveOrUpdateEvent @event)
{
var session = @event.Session;
EntityEntry entry = session.PersistenceContext.GetEntry(@event.Entity);
if (entry != null && entry.Persister.IsMutable && entry.Status == Status.ReadOnly)
{
entry.BackSetStatus(Status.Loaded);
CascadeOnUpdate(@event, entry.Persister, @event.Entry);
}
}
private static void CascadeOnUpdate(SaveOrUpdateEvent @event, IEntityPersister entityPersister,
object entityEntry)
{
IEventSource source = @event.Session;
source.PersistenceContext.IncrementCascadeLevel();
try
{
new Cascade(ResetReadOnly, CascadePoint.BeforeFlush, source).CascadeOn(entityPersister, entityEntry);
}
finally
{
source.PersistenceContext.DecrementCascadeLevel();
}
}
}
我们将其应用到NH中,因此:
public static ISessionFactory CreateSessionFactory(IPersistenceConfigurer dbConfig, Action<MappingConfiguration> mappingConfig, bool enabledChangeTracking,bool enabledAuditing, int queryTimeout)
{
return Fluently.Configure()
.Database(dbConfig)
.Mappings(mappingConfig)
.Mappings(x => x.FluentMappings.AddFromAssemblyOf<__AuditEntity>())
.ExposeConfiguration(x => Configure(x, enabledChangeTracking, enabledAuditing,queryTimeout))
.BuildSessionFactory();
}
/// <summary>
/// Configures the specified config.
/// </summary>
/// <param name="config">The config.</param>
/// <param name="enableChangeTracking">if set to <c>true</c> [enable change tracking].</param>
/// <param name="queryTimeOut">The query time out in minutes.</param>
private static void Configure(NHibernate.Cfg.Configuration config, bool enableChangeTracking, bool enableAuditing, int queryTimeOut)
{
config.SetProperty(NHibernate.Cfg.Environment.Hbm2ddlKeyWords, "none");
if (queryTimeOut > 0)
{
config.SetProperty("command_timeout", (TimeSpan.FromMinutes(queryTimeOut).TotalSeconds).ToString());
}
if (!enableChangeTracking)
{
config.AppendListeners(NHibernate.Event.ListenerType.PostLoad, new[] { new Enact.Core.DB.NHib.Listeners.PostLoadEventListener() });
config.AppendListeners(NHibernate.Event.ListenerType.SaveUpdate, new[] { new Enact.Core.DB.NHib.Listeners.SaveUpdateEventListener() });
config.AppendListeners(NHibernate.Event.ListenerType.PostUpdate, new[] { new Enact.Core.DB.NHib.Listeners.PostUpdateEventListener() });
config.AppendListeners(NHibernate.Event.ListenerType.PostInsert, new[] { new Enact.Core.DB.NHib.Listeners.PostInsertEventListener() });
}
}