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我有一个使用 Fluent NHibernate 和 AutoMapper 的 ASP.NET MVC 应用程序。我主要使用 AutoMapper 将我的模型映射到 ViewModel，反之亦然。

在执行后者时，从我的视图模型映射回模型，我想知道如何将其映射到数据库中的特定实例，所以当我将更改提交回数据库时（使用我的 NHibernate 存储库层，通过我的服务层），更改将保持不变。

例子：

var advert = Mapper.Map<AdvertViewModel, Advert>(model);
_advertService.UpdateAdvert(advert); // then calls repo which commits current NHibernate trans * Nothing in the DB changes *

如果我尝试提交我的 NHibernate 会话，以便在数据库中更新这个广告，尽管广告被分配了正确的 Key/Id 作为映射的一部分，我猜是因为 NHibernate 会话对这个广告实例一无所知（？）它不会写掉更改。

因此，我想知道如何与 NHibernate 一起处理这种映射场景？

4

2 回答 2

4

您可以执行以下操作：

// fetch the domain model to update
var domainModelToUpdate = _advertService.Get(viewModel.Id);

// Map the properties that are present in the view model to the domain model
// leaving other properties intact
Mapper.Map<AdvertViewModel, Advert>(viewModel, domainModelToUpdate);

// Update the domain model
_advertService.UpdateAdvert(domainModelToUpdate);

但如果视图模型已经包含所有内容，则无需在更新之前获取域模型。您所要做的就是unsaved-value在您的身份列映射上指定 ，以便 NHibernate 知道实例是否是瞬态的，然后使用SaveOrUpdate：

Id(x => x.ID).WithUnsavedValue(0);

或者，如果您使用可空整数作为您的身份 pass null。

于 2012-06-27T07:31:19.963 回答
1

如果确实是会话问题 - 以下单例可能会帮助您

/// <summary>
/// Handles creation and management of sessions and transactions.  It is a singleton because 
/// building the initial session factory is very expensive. Inspiration for this class came 
/// from Chapter 8 of Hibernate in Action by Bauer and King.  Although it is a sealed singleton
/// you can use TypeMock (http://www.typemock.com) for more flexible testing.
/// </summary>
public sealed class NHibernateSessionManager
{
    #region Thread-safe, lazy Singleton

    System.IO.StreamWriter ConsoleWriter = null;

    /// <summary>
    /// This is a thread-safe, lazy singleton.  See http://www.yoda.arachsys.com/csharp/singleton.html
    /// for more details about its implementation.
    /// </summary>
    public static NHibernateSessionManager Instance
    {
        get
        {
            return Nested.NHibernateSessionManager;
        }
    }

    /// <summary>
    /// Initializes the NHibernate session factory upon instantiation.
    /// </summary>
    private NHibernateSessionManager()
    {
        InitSessionFactory();
    }

    /// <summary>
    /// Assists with ensuring thread-safe, lazy singleton
    /// </summary>
    private class Nested
    {
        static Nested() { }
        internal static readonly NHibernateSessionManager NHibernateSessionManager =
            new NHibernateSessionManager();
    }

    #endregion

    private void InitSessionFactory()
    {
        // Hold the config var
        FluentConfiguration config = Fluently.Configure();

        // Set the DB config
        MsSqlConfiguration dbConfig = MsSqlConfiguration.MsSql2005.ConnectionString(ConfigurationManager.ConnectionStrings["iSearchConnection"].ConnectionString);
        config.Database(dbConfig);

        // Load mappings from this assembly
        config.Mappings(m => m.FluentMappings.AddFromAssembly(Assembly.GetExecutingAssembly()));

        // Create session factory
        sessionFactory = config.BuildSessionFactory();
    }

    /// <summary>
    /// Allows you to register an interceptor on a new session.  This may not be called if there is already
    /// an open session attached to the HttpContext.  If you have an interceptor to be used, modify
    /// the HttpModule to call this before calling BeginTransaction().
    /// </summary>
    public void RegisterInterceptor(IInterceptor interceptor)
    {
        ISession session = ContextSession;

        if (session != null && session.IsOpen)
        {
            throw new CacheException("You cannot register an interceptor once a session has already been opened");
        }

        GetSession(interceptor);
    }

    public ISession GetSession()
    {
        return GetSession(null);
    }

    /// <summary>
    /// Gets a session with or without an interceptor.  This method is not called directly; instead,
    /// it gets invoked from other public methods.
    /// </summary>
    private ISession GetSession(IInterceptor interceptor)
    {
        ISession session = ContextSession;

        if (session == null)
        {
            if (interceptor != null)
            {
                session = sessionFactory.OpenSession(interceptor);
            }
            else
            {
                session = sessionFactory.OpenSession();
            }

            ContextSession = session;
        }

        return session;
    }

    /// <summary>
    /// Flushes anything left in the session and closes the connection.
    /// </summary>
    public void CloseSession()
    {
        ISession session = ContextSession;

        if (session != null && session.IsOpen)
        {
            session.Flush();
            session.Close();
        }

        if (ConsoleWriter != null)
        {
            ConsoleWriter.Flush();
            ConsoleWriter.Close();
        }

        ContextSession = null;
    }

    public void BeginTransaction()
    {
        ITransaction transaction = ContextTransaction;

        if (transaction == null)
        {
            transaction = GetSession().BeginTransaction();
            ContextTransaction = transaction;
        }
    }

    public void CommitTransaction()
    {
        ITransaction transaction = ContextTransaction;

        try
        {
            if (HasOpenTransaction())
            {
                transaction.Commit();
                ContextTransaction = null;
            }
        }
        catch (HibernateException)
        {
            RollbackTransaction();
            throw;
        }
    }

    public bool HasOpenTransaction()
    {
        ITransaction transaction = ContextTransaction;

        return transaction != null && !transaction.WasCommitted && !transaction.WasRolledBack;
    }

    public void RollbackTransaction()
    {
        ITransaction transaction = ContextTransaction;

        try
        {
            if (HasOpenTransaction())
            {
                transaction.Rollback();
            }

            ContextTransaction = null;
        }
        finally
        {
            CloseSession();
        }
    }

    /// <summary>
    /// If within a web context, this uses <see cref="HttpContext" /> instead of the WinForms 
    /// specific <see cref="CallContext" />.  Discussion concerning this found at 
    /// http://forum.springframework.net/showthread.php?t=572.
    /// </summary>
    private ITransaction ContextTransaction
    {
        get
        {
            if (IsInWebContext())
            {
                return (ITransaction)HttpContext.Current.Items[TRANSACTION_KEY];
            }
            else
            {
                return (ITransaction)CallContext.GetData(TRANSACTION_KEY);
            }
        }
        set
        {
            if (IsInWebContext())
            {
                HttpContext.Current.Items[TRANSACTION_KEY] = value;
            }
            else
            {
                CallContext.SetData(TRANSACTION_KEY, value);
            }
        }
    }

    /// <summary>
    /// If within a web context, this uses <see cref="HttpContext" /> instead of the WinForms 
    /// specific <see cref="CallContext" />.  Discussion concerning this found at 
    /// http://forum.springframework.net/showthread.php?t=572.
    /// </summary>
    private ISession ContextSession
    {
        get
        {
            if (IsInWebContext())
            {
                return (ISession)HttpContext.Current.Items[SESSION_KEY];
            }
            else
            {
                return (ISession)CallContext.GetData(SESSION_KEY);
            }
        }
        set
        {
            if (IsInWebContext())
            {
                HttpContext.Current.Items[SESSION_KEY] = value;
            }
            else
            {
                CallContext.SetData(SESSION_KEY, value);
            }
        }
    }

    private bool IsInWebContext()
    {
        return HttpContext.Current != null;
    }

    private const string TRANSACTION_KEY = "CONTEXT_TRANSACTION";
    private const string SESSION_KEY = "CONTEXT_SESSION";
    private ISessionFactory sessionFactory;
}

从一些 NHibernate 大师网站上得到了这个——虽然我不记得是哪一个了——它基本上在你所处的任何应用程序上下文中为你跟踪和重建会话——对我的项目非常有用。

然后你只需在管理器上调用标准方法：

ISession ctx = NHibernateSessionManager.Instance.GetSession();

try
{
    ctx.BeginTransaction();
    ctx.Update(entity);
    ctx.CommitTransaction();
}

您可能已经实现了一个很好的会话处理 - 但从信息来看，您遇到的问题听起来像是一个会话问题，所以如果这有帮助，请告诉我

于 2012-06-27T12:30:30.733 回答