使用NHibernate过程中 出现的奇怪问题

Question

本人刚接触NHibernate 做了一个小demo 代码如下 private void Form1_Load(object sender, EventArgs e)
        {
            Configuration cfg = new Configuration().Configure();
            ISessionFactory Factory = cfg.BuildSessionFactory();
            ISession session = Factory.OpenSession();
            IQuery query = session.CreateQuery("from Login");
            IList<Login> list = query.List<Login>();            foreach (Login login in list)
            {
                MessageBox.Show(login.Name);
            }
        }运行 没问题。
接下来的 我将代码小小改动了一下public class Nhelp
    {
        public IList<T> Query<T>()
        {
            Configuration cfg = new Configuration().Configure();
            ISessionFactory Factory = cfg.BuildSessionFactory();
            ISession session = Factory.OpenSession();
            IQuery query = session.CreateQuery("from login");
            IList<T> list = query.List<T>();
            return list;
        }
    }
 写了一个 Nhelp 类 
调用 private void Form1_Load(object sender, EventArgs e)
        {
            Nhelp help = new Nhelp();
            IList<Login> list = help.Query<Login>();
            foreach (Login login in list)
            {
                MessageBox.Show(login.Name);
            }
        }只是做了一个简单的封装，运行
在 Nhelp 类的 IQuery query = session.CreateQuery("from login");
出 报错  login is not mapped [from login]
错误代码
未处理 NHibernate.Hql.Ast.ANTLR.QuerySyntaxException
  Message="login is not mapped [from login]"
  Source="NHibernate"
  QueryString="from login"
  StackTrace:
       在 NHibernate.Hql.Ast.ANTLR.SessionFactoryHelperExtensions.RequireClassPersister(String name)
       在 NHibernate.Hql.Ast.ANTLR.Tree.FromElementFactory.AddFromElement()
       在 NHibernate.Hql.Ast.ANTLR.Tree.FromClause.AddFromElement(String path, IASTNode alias)
       在 NHibernate.Hql.Ast.ANTLR.HqlSqlWalker.CreateFromElement(String path, IASTNode pathNode, IASTNode alias, IASTNode propertyFetch)
       在 NHibernate.Hql.Ast.ANTLR.HqlSqlWalker.fromElement()
       在 NHibernate.Hql.Ast.ANTLR.HqlSqlWalker.fromElementList()
       在 NHibernate.Hql.Ast.ANTLR.HqlSqlWalker.fromClause()
       在 NHibernate.Hql.Ast.ANTLR.HqlSqlWalker.unionedQuery()
       在 NHibernate.Hql.Ast.ANTLR.HqlSqlWalker.query()
       在 NHibernate.Hql.Ast.ANTLR.HqlSqlWalker.selectStatement()
       在 NHibernate.Hql.Ast.ANTLR.HqlSqlWalker.statement()
       在 NHibernate.Hql.Ast.ANTLR.HqlSqlTranslator.Translate()
       在 NHibernate.Hql.Ast.ANTLR.QueryTranslatorImpl.Analyze(String collectionRole)
       在 NHibernate.Hql.Ast.ANTLR.QueryTranslatorImpl.DoCompile(IDictionary`2 replacements, Boolean shallow, String collectionRole)
       在 NHibernate.Hql.Ast.ANTLR.QueryTranslatorImpl.Compile(IDictionary`2 replacements, Boolean shallow)
       在 NHibernate.Hql.Ast.ANTLR.ASTQueryTranslatorFactory.CreateQueryTranslators(IASTNode ast, String queryIdentifier, String collectionRole, Boolean shallow, IDictionary`2 filters, ISessionFactoryImplementor factory)
       在 NHibernate.Hql.Ast.ANTLR.ASTQueryTranslatorFactory.CreateQueryTranslators(String queryString, String collectionRole, Boolean shallow, IDictionary`2 filters, ISessionFactoryImplementor factory)
       在 NHibernate.Engine.Query.HQLStringQueryPlan.CreateTranslators(String hql, String collectionRole, Boolean shallow, IDictionary`2 enabledFilters, ISessionFactoryImplementor factory)
       在 NHibernate.Engine.Query.HQLStringQueryPlan..ctor(String hql, String collectionRole, Boolean shallow, IDictionary`2 enabledFilters, ISessionFactoryImplementor factory)
       在 NHibernate.Engine.Query.HQLStringQueryPlan..ctor(String hql, Boolean shallow, IDictionary`2 enabledFilters, ISessionFactoryImplementor factory)
       在 NHibernate.Engine.Query.QueryPlanCache.GetHQLQueryPlan(String queryString, Boolean shallow, IDictionary`2 enabledFilters)
       在 NHibernate.Impl.AbstractSessionImpl.GetHQLQueryPlan(String query, Boolean shallow)
       在 NHibernate.Impl.AbstractSessionImpl.CreateQuery(String queryString)
       在 demo.Nhelp.Query[T]() 位置 D:\Projects\WindowApp\demo\Nhelp.cs:行号 22
       在 demo.Form1.Form1_Load(Object sender, EventArgs e) 位置 D:\Projects\WindowApp\PanasonicMES\PanasonicMES\Form1.cs:行号 39
       在 System.Windows.Forms.Form.OnLoad(EventArgs e)
       在 System.Windows.Forms.Form.OnCreateControl()
       在 System.Windows.Forms.Control.CreateControl(Boolean fIgnoreVisible)
       在 System.Windows.Forms.Control.CreateControl()
       在 System.Windows.Forms.Control.WmShowWindow(Message& m)
       在 System.Windows.Forms.Control.WndProc(Message& m)
       在 System.Windows.Forms.ScrollableControl.WndProc(Message& m)
       在 System.Windows.Forms.ContainerControl.WndProc(Message& m)
       在 System.Windows.Forms.Form.WmShowWindow(Message& m)
       在 System.Windows.Forms.Form.WndProc(Message& m)
       在 System.Windows.Forms.Control.ControlNativeWindow.OnMessage(Message& m)
       在 System.Windows.Forms.Control.ControlNativeWindow.WndProc(Message& m)
       在 System.Windows.Forms.NativeWindow.DebuggableCallback(IntPtr hWnd, Int32 msg, IntPtr wparam, IntPtr lparam)
       在 System.Windows.Forms.SafeNativeMethods.ShowWindow(HandleRef hWnd, Int32 nCmdShow)
       在 System.Windows.Forms.Control.SetVisibleCore(Boolean value)
       在 System.Windows.Forms.Form.SetVisibleCore(Boolean value)
       在 System.Windows.Forms.Control.set_Visible(Boolean value)
       在 System.Windows.Forms.Application.ThreadContext.RunMessageLoopInner(Int32 reason, ApplicationContext context)
       在 System.Windows.Forms.Application.ThreadContext.RunMessageLoop(Int32 reason, ApplicationContext context)
       在 System.Windows.Forms.Application.Run(Form mainForm)
       在 PanasonicMES.Program.Main() 位置 D:\Projects\WindowApp\demo\Program.cs:行号 17
       在 System.AppDomain._nExecuteAssembly(Assembly assembly, String[] args)
       在 System.AppDomain.ExecuteAssembly(String assemblyFile, Evidence assemblySecurity, String[] args)
       在 Microsoft.VisualStudio.HostingProcess.HostProc.RunUsersAssembly()
       在 System.Threading.ThreadHelper.ThreadStart_Context(Object state)
       在 System.Threading.ExecutionContext.Run(ExecutionContext executionContext, ContextCallback callback, Object state)
       在 System.Threading.ThreadHelper.ThreadStart()
  InnerException: 实在不知道 错在何处 求解

Answer 1

Nhelp 和窗体在一个项目里？一个数据库有一个 SessionFactory 就行了，不要每次重建，Session 用完要关闭

Answer 2

是的 在一个项目里面  
一个数据库有一个 SessionFactory 就行了，不要每次重建，Session 用完要关闭 不明白，相同的代码 在窗体里面 没问题 ，单独用一个类封装起来 就不行
这个和SessionFactory 没关系吧

Answer 3

IQuery query = session.CreateQuery("from login");
区分大小写吗？
IQuery query = session.CreateQuery("from Login");

Answer 4

晕菜，是大小写问题，hql里的实体类名是大小写敏感的。Query<T> 每次调用都会执行这两句：            Configuration cfg = new Configuration().Configure();
            ISessionFactory Factory = cfg.BuildSessionFactory();这是没必要的，浪费资源。在应用程序启动的时候配置一次就可以了。session 用完之后要关闭: session.Close，建议把 session 放在 using 语句里。

Answer 5

HSQL 中session.CreateQuery("from login");login应该是实体的类名，不是表名