在具有多个连接的EF中执行Group By的正确方法是什么？

Question

我正在尝试在实体框架中执行一个在SQL中非常直接的查询，看起来它应该能够处理它，尽管我收到了一个转换错误。

以下声明：

Dim affiliateList = (
    From cl In objCxt.CustomerLocations
    Join cla In objCxt.CustomerLocation_Affiliation
        On cla.CustomerLocationKey Equals cl.CustomerLocationKey
    Join cl2 In objCxt.CustomerLocations
        On cl2.CustomerLocationKey Equals cla.AffiliateCustomerLocationKey
    Where cl.Removed = False _
        AndAlso cl.Active = True _
        AndAlso cl.CustomerKey = 3 _
        AndAlso cl2.Removed = False _
        AndAlso cl2.Active = True _
        AndAlso hsCustLocCodes.Any(Function(clc) clc.Equals(cl.Code, StringComparison.InvariantCultureIgnoreCase))
    ).
    GroupBy(Function(x) x.cl.Code).
    Select(Function(x) New With {.Code = x.Key, .AffiliateCode = x.Max(Function(y) y.cl2.Code)}).
    ToList()

产生以下错误：

Unable to cast the type 

'System.Linq.IGrouping`2[[System.String, mscorlib, Version=4.0.0.0, Culture=neutral, PublicKeyToken=b77a5c561934e089],[VB$AnonymousType_73`3[[SmaModelBase.CustomerLocation, SmaModelBase, Version=1.0.0.0, Culture=neutral, PublicKeyToken=null],[SmaModelBase.CustomerLocation_Affiliation, SmaModelBase, Version=1.0.0.0, Culture=neutral, PublicKeyToken=null],[SmaModelBase.CustomerLocation, SmaModelBase, Version=1.0.0.0, Culture=neutral, PublicKeyToken=null]], SmaModelBase, Version=1.0.0.0, Culture=neutral, PublicKeyToken=null]]' 

to type 

'System.Collections.Generic.IEnumerable`1[[VB$AnonymousType_73`3[[SmaModelBase.CustomerLocation, SmaModelBase, Version=1.0.0.0, Culture=neutral, PublicKeyToken=null],[SmaModelBase.CustomerLocation_Affiliation, SmaModelBase, Version=1.0.0.0, Culture=neutral, PublicKeyToken=null],[SmaModelBase.CustomerLocation, SmaModelBase, Version=1.0.0.0, Culture=neutral, PublicKeyToken=null]], SmaModelBase, Version=1.0.0.0, Culture=neutral, PublicKeyToken=null]]'

LINQ to Entities only supports casting EDM primitive or enumeration types.

如果我在SQL中这样做，它将看起来像这样：

select
    cl.Code,
    AffliateCode = max(cl2.Code)
from 
    CustomerLocation cl
    inner join CustomerLocation_Affiliation cl_a
        on cl_a.CustomerLocationKey = cl.CustomerLocationKey
    inner join CustomerLocation cl2
        on cl2.CustomerLocationKey = cl_a.AffiliateCustomerLocationKey
where
    cl.Removed = 0
    and
    cl.Active = 1
    and 
    cl.CustomerKey = 3
    and
    cl2.Removed = 0
    and
    cl2.Active = 1
    and
    cl.Code in ('123', 'abc')
group by 
    cl.code

有没有办法完成我在EF尝试做的事情？