NHibernate -延迟加载问题-初始化[]-无法初始化代理-没有会话."}

你好，我使用的是Fluent NHibernate，我对延迟加载有点困惑。

1. 我查询了数据库中的对象
2. 修改对象属性
3. 使用此对象更新数据库

代码如下:

public class Credentials
{
    public virtual int Id { get; set; }
    public virtual string Nick { get; set; }
    public virtual string Password { get; set; }
}
public class CredentialsMap : ClassMap<Credentials>
{
    public CredentialsMap()
    {
        Id(x => x.Id);
        Map(x => x.Nick).Column("NICK");
        Map(x => x.Password).Column("PASSWORD");
        Table("R_CREDENTAILS");
    }
}
public class Status
{
    public virtual int Id { get; set; }
    public virtual string Msg { get; set; }
    public virtual DateTime AddTime { get; set; }
}
public class StatusMap : ClassMap<Status>
{
    public StatusMap()
    {
        Id(x => x.Id);
        Map(x => x.Msg).Column("MESSAGE");
        Map(x => x.AddTime).Column("ADD_TIME");
        Table("R_STATUS");
    }
}
public class Account
{
    public virtual int Id { get; set; }
    public virtual string SelfNick { get; set; }
    public virtual Credentials Credentials { get; set; }
    public virtual Status Status { get; set; }
}
public class AccountMap : ClassMap<Account>
{
    public AccountMap()
    {
        Id(x => x.Id);
        Map(x => x.SelfNick).Column("SELF_NICK");
        References(x => x.Credentials)
            .Column("CREDENTIALS_ID")
            .ForeignKey();
        References(x => x.Status)
            .Column("STATUS_ID")
            .ForeignKey();
        Table("R_ACCOUNTS");
    }
}

NHibernate配置类

public class NHiberanteHelper
{
    private static ISessionFactory _sessionFactory;
    private static ISessionFactory SessionFactory
    {
        get
        {
            if (_sessionFactory == null)
                InitializeSessionFactory();
            return _sessionFactory;
        }
    }
    private static void InitializeSessionFactory()
    {
        _sessionFactory = Fluently.Configure()
            .Database(MsSqlConfiguration.MsSql2008
                          .ConnectionString(
                               @"Server=TEST'SQLEXPRESS;Database=SimpleNHibernate;Trusted_Connection=True;").
                               ShowSql()
                              )
            .Mappings(m => m.FluentMappings.AddFromAssemblyOf<Account>().Conventions.Add( DefaultCascade.All()))
            .ExposeConfiguration(cfg => new SchemaUpdate(cfg).Execute(true, true))
            .BuildSessionFactory();
    }
    public static ISession OpenSession()
    {
        return SessionFactory.OpenSession();
    }
}

用法:

    public class LoginDbHelper
    {
        public static Account GetAccount(string nick)
        {
            using (var session = NHiberanteHelper.OpenSession())
            {
                var account = (session.QueryOver<Account>()
                    .JoinQueryOver<Credentials>(a => a.Credentials)
                    .Where(c => c.Nick == nick));
                if (account != null)
                    return account.SingleOrDefault();
                return null;
            }
        }
        public static void SaveOrUpdateAccount(Account account)
        {
            using (var session = NHiberanteHelper.OpenSession())
            {
                using (var trans = session.BeginTransaction())
                {
                    session.SaveOrUpdate(account);
                    trans.Commit();
                }
            }
        }
   }

问题代码:

var actualAccount = LoginDbHelper.GetAccount(nick);
//modify
actualAccount.Status.Msg = "New status 2";
actualAccount.Status.AddTime = DateTime.Now;

LoginDbHelper.SaveOrUpdateAccount(account);

我得到这个错误:

{"Initializing[NHibernateSample1.Status#1]-Could not initialize proxy - no Session."}

异常堆栈

:

 at NHibernate.Proxy.AbstractLazyInitializer.Initialize() in d:'CSharp'NH'NH'nhibernate'src'NHibernate'Proxy'AbstractLazyInitializer.cs:line 113
   at NHibernate.Proxy.AbstractLazyInitializer.GetImplementation() in d:'CSharp'NH'NH'nhibernate'src'NHibernate'Proxy'AbstractLazyInitializer.cs:line 191
   at NHibernate.ByteCode.Castle.LazyInitializer.Intercept(IInvocation invocation) in d:'CSharp'NH'NH'nhibernate'src'NHibernate.ByteCode.Castle'LazyInitializer.cs:line 61
   at Castle.DynamicProxy.AbstractInvocation.Proceed()
   at Castle.Proxies.StatusProxy.set_Msg(String value)
   at NHibernateSample1.Program.Main(String[] args) in E:'C# PROJECTS'Samples'SimpleNHibernateClient'NHibernateSample1'Program.cs:line 215
   at System.AppDomain._nExecuteAssembly(RuntimeAssembly assembly, String[] args)
   at System.AppDomain.ExecuteAssembly(String assemblyFile, Evidence assemblySecurity, String[] args)
   at Microsoft.VisualStudio.HostingProcess.HostProc.RunUsersAssembly()

我谷歌它，我认为这是由于延迟加载，因为在方法GetAccount我关闭SESSION。这是我第一次尝试使用NHibernate，所以如何正确解决这个问题?这是可能的禁用LAZY LOADING如果是，怎么做?

.Conventions.Add( DefaultCascade.All(), DefaultLazy.Never() )

    // method
    public static Account GetAccount(string nick, ISession session) 
    {   
     var account = (session.QueryOver<Account>().JoinQueryOver<Credentials>(a => a.Credentials).Where(c => c.Nick == nick));   
           if (account != null)                      
            return account.SingleOrDefault();                    
    return null;  
    }
// usage
    var actualAccount = LoginDbHelper.GetAccount(nick);   
    actualAccount.Status.AddTime = DateTime.Now;   
    using (var session = NHiberanteHelper.OpenSession())  
    LoginDbHelper.SaveOrUpdateAccount(account, session); 

if (account != null)
    return account.SingleOrDefault();

if (account != null)
{
    var returnValue = account.SingleOrDefault();
    if (returnValue != null)
    {
        returnValue.Status.Msg = returnValue.Status.Msg;//Cause to load the lazy object now
    }
    return returnValue;
}