Linq到NHibernate的多個OrderBy調用

Question

我遇到麻煩，在我的Linq的NHibernate查詢中有多個字段排序。有人知道什麼可能是錯的，或者是否有解決辦法？

代碼：

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); 

我已經試過多次排序依據呼叫替換ThenBy。同樣的結果。如果我註釋掉兩個ThenBy調用，該方法很好用。

錯誤我收到：

（從我在項目排序依據我：

 
    [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

這在我看來像一個Linq到NHybernate的bug。一種可能的解決方法是在排序之前轉換爲數組。一個潛在的巨大缺點是你不能在枚舉之前使用Skip（）和Take（）來限制結果，所以這對你來說可能不夠。

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

雖然我不認爲這會有所作爲，如果你做你的LINQ這樣會發生什麼。 prop1，i.prop2，i.prop3）.Skip（...）。Take（...）。ToArray（）;