NHibernate：System.Argument异常：已添加具有相同键的项目

我遇到了一个很难重现的偶发错误。我的第一个猜测是，不知怎的，我有一个泄漏的休眠会话，但是当我运行休眠分析器 http://nhprof.com/，我没有看到太多异常。

• MVC 2.0
• 流畅版本1.1.0.685
• NHibernate 版本 2.1.2.4000

异常：System.ArgumentException： 具有相同密钥的项目已经 已添加。

堆栈跟踪：位于 System.Collections.Generic.Dictionary2.Insert(TKey key, TValue value, Boolean add) at NHibernate.Util.ThreadSafeDictionary2.添加(TKey 键，TValue 值）位于 NHibernate.SqlTypes.SqlTypeFactory.GetTypeWithLen[T](Int32 长度，TypeWithLenCreateDelegate 创建委托）在 NHibernate.Type.EnumStringType..ctor(类型 枚举类，Int32 长度）

我正在使用存储库模型。这是我的存储库类。

public sealed class Repository<T> : IRepository<T> where T : CoreObjectBase
{
    #region IRepository<T> Members

    private ISession Session
    {
        get
        {
            return new SessionHelper().GetSession();
        }
    }

    public IQueryable<T> GetAll()
    {
        return (from entity in Session.Linq<T>() select entity);
    }

    public T GetById(int id)
    {
        return Session.Get<T>(id);
    }

    public void Save(params T[] entities)
    {
        using (ITransaction tx = Session.BeginTransaction())
        {
            for (int x = 0; x < entities.Count(); x++)
            {
                var entity = entities[x];

                entity.Validate();

                Session.SaveOrUpdate(entities[x]);

                if (x == entities.Count() - 1 || (x != 0 && x % 20 == 0)) //20 is the batch size
                {
                    Session.Flush();
                    Session.Clear();
                }
            }
            tx.Commit();
        }
    }

    public void SaveWithDependence<K>(T entity, K dependant) where K : CoreObjectBase
    {
        entity.Validate();
        dependant.Validate();

        using (ITransaction tx = Session.BeginTransaction())
        {
            Session.SaveOrUpdate(entity);
            Session.SaveOrUpdate(dependant);
            tx.Commit();
        }
    }

    public void Save(T entity)
    {
        entity.Validate();

        using (ITransaction tx = Session.BeginTransaction())
        {
            Session.SaveOrUpdate(entity);
            tx.Commit();
        }
    }

    public void Delete(T entity)
    {
        using (ITransaction tx = Session.BeginTransaction())
        {
            Session.Delete(entity);
            tx.Commit();
        }
    }

    public T GetOne(QueryBase<T> query)
    {
        var result = query.SatisfyingElementFrom(Session.Linq<T>());

        return result;

        //return query.SatisfyingElementFrom(Session.Linq<T>());
    }

    public IQueryable<T> GetList(QueryBase<T> query)
    {
        return query.SatisfyingElementsFrom(Session.Linq<T>());
    }

    /// <summary>
    /// remove the sepcific object from level 1 cache so it can be refreshed from the database
    /// </summary>
    /// <param name="entity"></param>
    public void Evict(T entity)
    {
        Session.Evict(entity);
    }
    #endregion
}

这是我的会话助手，改编自this http://code.google.com/p/dot-net-reference-app/source/browse/trunk/src/Infrastructure/Impl/HybridSessionBuilder.cs.

public sealed class SessionHelper
{
    private static ISessionFactory _sessionFactory;
    private static ISession _currentSession;

    public ISession GetSession()
    {
        ISessionFactory factory = getSessionFactory();
        ISession session = getExistingOrNewSession(factory);
        return session;
    }

    private ISessionFactory getSessionFactory()
    {
        if (_sessionFactory == null)
        {
            _sessionFactory = BuildSessionFactory();
        }

        return _sessionFactory;
    }

    private ISessionFactory BuildSessionFactory()
    {
        return Fluently.Configure().Database(
            FluentNHibernate.Cfg.Db.MsSqlConfiguration.MsSql2005
                .ConnectionString(c => c
                    .FromConnectionStringWithKey("MyDatabase"))
                    .AdoNetBatchSize(20))
                .Mappings(m => m.FluentMappings.AddFromAssemblyOf<SessionHelper>())
                .BuildSessionFactory();
    }

    private ISession getExistingOrNewSession(ISessionFactory factory)
    {
        if (HttpContext.Current != null)
        {
            ISession session = GetExistingWebSession();
            if (session == null)
            {
                session = openSessionAndAddToContext(factory);
            }
            else if (!session.IsOpen)
            {
                session = openSessionAndAddToContext(factory);
            }

            return session;
        }

        if (_currentSession == null)
        {
            _currentSession = factory.OpenSession();
        }
        else if (!_currentSession.IsOpen)
        {
            _currentSession = factory.OpenSession();
        }

        return _currentSession;
    }

    public ISession GetExistingWebSession()
    {
        return HttpContext.Current.Items[GetType().FullName] as ISession;
    }

    private ISession openSessionAndAddToContext(ISessionFactory factory)
    {
        ISession session = factory.OpenSession();
        HttpContext.Current.Items.Remove(GetType().FullName);
        HttpContext.Current.Items.Add(GetType().FullName, session);
        return session;
    }
}

有什么想法或建议可以避免这个问题吗？

问题是，那SessionHelper不是线程安全的。它可能会构建多个会话工厂（这是单例的糟糕实现），这反过来可能会导致您看到的错误。

我建议使用夏普架构 http://www.sharparchitecture.net/作为指导。