Linq GroupJoin例外

Question

我的代码中有类似的查询尝试执行组连接：

var query = from client in _clientsRepository.Query()
            join order in _ordersRepository.Query()
            on client.Id equals order.Client.Id into orders
            select new Model(client, orders);

它与101 Linq样本几乎完全相同，但是，每当我运行它时，我得到它 以下例外：

  

{＆＃34;无法转换类型的对象   ＆＃39; Remotion.Linq.Clauses.GroupJoinClause＆＃39;输入   ＆＃39; Remotion.Linq.Clauses.FromClauseBase＆＃39;＆＃34;}

不确定为什么会这样，我无法在网上找到任何答案。

这是堆栈跟踪：

 at NHibernate.Linq.GroupJoin.GroupJoinAggregateDetectionVisitor.VisitQuerySourceReferenceExpression(QuerySourceReferenceExpression expression)
   at NHibernate.Linq.Visitors.NhExpressionTreeVisitor.VisitExpression(Expression expression)
   at Remotion.Linq.Parsing.ExpressionTreeVisitor.VisitAndConvert[T](T expression, String methodName)
   at Remotion.Linq.Parsing.ExpressionTreeVisitor.VisitList[T](ReadOnlyCollection`1 list, Func`2 visitMethod)
   at Remotion.Linq.Parsing.ExpressionTreeVisitor.VisitNewExpression(NewExpression expression)
   at NHibernate.Linq.Visitors.NhExpressionTreeVisitor.VisitExpression(Expression expression)
   at NHibernate.Linq.GroupJoin.GroupJoinAggregateDetectionVisitor.Visit(IEnumerable`1 groupJoinClause, Expression selectExpression)
   at NHibernate.Linq.GroupJoin.AggregatingGroupJoinRewriter.ReWrite(QueryModel model)
   at NHibernate.Linq.Visitors.QueryModelVisitor.GenerateHqlQuery(QueryModel queryModel, VisitorParameters parameters, Boolean root)
   at NHibernate.Linq.NhLinqExpression.Translate(ISessionFactoryImplementor sessionFactory)
   at NHibernate.Hql.Ast.ANTLR.ASTQueryTranslatorFactory.CreateQueryTranslators(String queryIdentifier, IQueryExpression queryExpression, String collectionRole, Boolean shallow, IDictionary`2 filters, ISessionFactoryImplementor factory)
   at NHibernate.Engine.Query.HQLExpressionQueryPlan.CreateTranslators(String expressionStr, IQueryExpression queryExpression, String collectionRole, Boolean shallow, IDictionary`2 enabledFilters, ISessionFactoryImplementor factory)
   at NHibernate.Engine.Query.QueryPlanCache.GetHQLQueryPlan(IQueryExpression queryExpression, Boolean shallow, IDictionary`2 enabledFilters)
   at NHibernate.Impl.AbstractSessionImpl.GetHQLQueryPlan(IQueryExpression queryExpression, Boolean shallow)
   at NHibernate.Impl.AbstractSessionImpl.CreateQuery(IQueryExpression queryExpression)
   at NHibernate.Linq.DefaultQueryProvider.Execute(Expression expression)
   at NHibernate.Linq.DefaultQueryProvider.Execute[TResult](Expression expression)
   at Remotion.Linq.QueryableBase`1.GetEnumerator()
   at System.Linq.SystemCore_EnumerableDebugView`1.get_Items()

有什么想法吗？