LINQ到实体无​​法识别方法'布尔包含[小数] [英] LINQ to Entities does not recognize the method 'Boolean Contains[Decimal]

问题描述

我是新来的LINQ，所以我在这里混淆pretty。我有一个数据库，并尝试以下code运行。

I am new to LINQ, so I am pretty confused here. I have a database and try to run following code.

IQueryable<decimal> location_ids = (from m in _db.Admins
                                    where m.UserId.Equals("c5d3dc0e-81e6-4d6b-a9c3-faa802e10b7d")
                                    select m.LocationId);
if (!location_ids.Contains(new Decimal(conf.umisteni.Budova.ID)))

在if语句，我得到一个错误，我不明白，我也不知道，如何解决这个问题：

On the if statement I get an error I don't understand, nor do I know, how to solve it:

System.NotSupportedException: LINQ to Entities does not recognize the method 'Boolean Contains[Decimal](System.Linq.IQueryable`1[System.Decimal], System.Decimal)' method, and this method cannot be translated into a store expression.
  at System.Data.Objects.ELinq.ExpressionConverter.MethodCallTranslator.DefaultTranslator.Translate(ExpressionConverter parent, MethodCallExpression call)

任何想法？

推荐答案

使用LINQ到对象的IEnumerable将让你使用包含（十进制）上查询的结果。

Using Linq-to-Objects IEnumerable will let you use Contains(Decimal) on the result of the query.

IEnumerable<decimal> location_ids = (from m in _db.Admins
                                    where m.UserId.Equals("c5d3dc0e-81e6-4d6b-a9c3-faa802e10b7d")
                                    select m.LocationId);

但是，为什么不只是扩大where子句：

However, why not just expand the where clause:

IEnumerable<decimal> location_ids = (from m in _db.Admins
                                    where m.UserId.Equals("c5d3dc0e-81e6-4d6b-a9c3-faa802e10b7d") && (m.LocationId == conf.umisteni.Budova.ID)
                                    select m.LocationId);
if (!location_ids.Any())

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