Linq到NHibernate的多个OrderBy调用

Question

我遇到麻烦，在我的Linq的NHibernate查询中有多个字段排序。有人知道什么可能是错的，或者是否有解决办法？

代码：

IQueryable<AgendaItem> items = _agendaRepository.GetAgendaItems(location) 
    .Where(item => item.Minutes.Contains(query) || item.Description.Contains(query)); 

int total = items.Count(); 

var results = items 
    .OrderBy(item => item.Agenda.Date) 
    .ThenBy(item => item.OutcomeType) 
    .ThenBy(item => item.OutcomeNumber) 
    .Skip((page - 1)*pageSize) 
    .Take(pageSize) 
    .ToArray(); 

return new SearchResult(query, total, results); 

我已经试过多次排序依据呼叫替换ThenBy。同样的结果。如果我注释掉两个ThenBy调用，该方法很好用。

错误我收到：

（从我在项目排序依据我：

 
    [SqlException (0x80131904): Invalid column name '__hibernate_sort_expr_0____hibernate_sort_expr_1__'. 
    Invalid column name '__hibernate_sort_expr_0____hibernate_sort_expr_1__'.] 
     System.Data.SqlClient.SqlConnection.OnError(SqlException exception, Boolean breakConnection) +1948826 
     System.Data.SqlClient.SqlInternalConnection.OnError(SqlException exception, Boolean breakConnection) +4844747 
     System.Data.SqlClient.TdsParser.ThrowExceptionAndWarning(TdsParserStateObject stateObj) +194 
     System.Data.SqlClient.TdsParser.Run(RunBehavior runBehavior, SqlCommand cmdHandler, SqlDataReader dataStream, BulkCopySimpleResultSet bulkCopyHandler, TdsParserStateObject stateObj) +2392 

    [ADOException: could not execute query 
    [ SELECT this_.Id as Id5_2_, this_.AgendaId as AgendaId5_2_, this_.Description as Descript3_5_2_, this_.OutcomeType as OutcomeT4_5_2_, this_.OutcomeNumber as OutcomeN5_5_2_, this_.Minutes as Minutes5_2_, agenda1_.Id as Id2_0_, agenda1_.LocationId as LocationId2_0_, agenda1_.Date as Date2_0_, location2_.Id as Id7_1_, location2_.Name as Name7_1_ FROM AgendaItem this_ left outer join Agenda agenda1_ on this_.AgendaId=agenda1_.Id left outer join Location location2_ on agenda1_.LocationId=location2_.Id WHERE location2_.Id = ? and (this_.Minutes like ? or this_.Description like ?) ORDER BY agenda1_.Date asc, this_.OutcomeType asc, this_.OutcomeNumber asc ] 
    Positional parameters: #0>1 #0>%Core% #0>%Core% 
    [SQL: SELECT this_.Id as Id5_2_, this_.AgendaId as AgendaId5_2_, this_.Description as Descript3_5_2_, this_.OutcomeType as OutcomeT4_5_2_, this_.OutcomeNumber as OutcomeN5_5_2_, this_.Minutes as Minutes5_2_, agenda1_.Id as Id2_0_, agenda1_.LocationId as LocationId2_0_, agenda1_.Date as Date2_0_, location2_.Id as Id7_1_, location2_.Name as Name7_1_ FROM AgendaItem this_ left outer join Agenda agenda1_ on this_.AgendaId=agenda1_.Id left outer join Location location2_ on agenda1_.LocationId=location2_.Id WHERE location2_.Id = ? and (this_.Minutes like ? or this_.Description like ?) ORDER BY agenda1_.Date asc, this_.OutcomeType asc, this_.OutcomeNumber asc]] 
     NHibernate.Loader.Loader.DoList(ISessionImplementor session, QueryParameters queryParameters) +258 
     NHibernate.Loader.Loader.ListIgnoreQueryCache(ISessionImplementor session, QueryParameters queryParameters) +18 
     NHibernate.Loader.Loader.List(ISessionImplementor session, QueryParameters queryParameters, ISet`1 querySpaces, IType[] resultTypes) +87 
     NHibernate.Impl.SessionImpl.List(CriteriaImpl criteria, IList results) +342 
     NHibernate.Impl.CriteriaImpl.List(IList results) +41 
     NHibernate.Impl.CriteriaImpl.List() +35 
     NHibernate.Linq.CriteriaResultReader`1.List() in C:\home\dev\tools\NHibernate\NHibernateContribSrc\src\NHibernate.Linq\src\NHibernate.Linq\CriteriaResultReader.cs:22 
     NHibernate.Linq.d__0.MoveNext() in C:\home\dev\tools\NHibernate\NHibernateContribSrc\src\NHibernate.Linq\src\NHibernate.Linq\CriteriaResultReader.cs:27 

Answer 1

这在我看来像一个Linq到NHybernate的bug。一种可能的解决方法是在排序之前转换为数组。一个潜在的巨大缺点是你不能在枚举之前使用Skip（）和Take（）来限制结果，所以这对你来说可能不够。

var results = items 
    .ToArray() 
    .OrderBy(item => item.Agenda.Date) 
    .ThenBy(item => item.OutcomeType) 
    .ThenBy(item => item.OutcomeNumber) 
    .Skip((page - 1)*pageSize) 
    .Take(pageSize) 

Answer 2

虽然我不认为这会有所作为，如果你做你的LINQ这样会发生什么。 prop1，i.prop2，i.prop3）.Skip（...）。Take（...）。ToArray（）;