Linq到实体错误 [英] Linq to Entitities Error

问题描述

你好，

我正在尝试从称为使用Linq到Entities的实践的表中获取一些值.

练习表包含以下内容.

PracticeID自动增量，
PracticeName nvarchar(10)，
等

现在我需要从此列表中获得3种做法.

Hello,

I am trying to fetch some values from a table called practices using Linq to Entities.

Practices table contains the following.

PracticeID AutoIncrement,
PracticeName nvarchar(10),
etc.

now i need to get 3 practices from this list.

stirng [] pras = new string [] {"1", "3", "5"}

 AuthenticationEntities authEntity = new AuthenticationEntities();



                    List<practices> prac = (from p in authEntity.Practices
                                            where pras.Contains(p.PracticeID.ToString())
                                            select new Practices
                                            {
                                                Practice = p.PracticeName
                                            }).ToList<practices>();

但这显示为错误

LINQ to Entities无法识别方法"System.String ToString()"，因此该方法无法转换为商店表达式.

But it is showing as error

LINQ to Entities does not recognize the method ''System.String ToString()'' method, and this method cannot be translated into a store expression.

Kindly help.

推荐答案

为什么不将数组声明为int类型(或将该字段定义为任何数字类型)?

Why not declare the array as int type (or whatever numeric type the field is defined as)?

int [] pras = new int[] {1, 3, 5};

var authEntity = new AuthenticationEntities();

var prac = (from p in authEntity.Practices
            where pras.Contains(p.PracticeID)
            select new Practices
            {
                Practice = p.PracticeName
            })
            .ToList<Practices>();

请参阅以下示例.

http://msdn.microsoft.com/en-us/vstudio/bb737939#strcont [ ^ ]

您可以使用contains找到文本.
在这里，您的PracticeID为Integer，并且将其与字符串进行比较，因此存在转换问题. 我认为你不能做这样的演员
我建议为此使用存储过程.

谢谢，
Viprat Shah

see the below example.

http://msdn.microsoft.com/en-us/vstudio/bb737939#strcont[^]

you can find the text using contains.
here your PracticeID is Integer and you are comparing it with string so there is casting problem.
i think you can`t do casting like this
i suggest use stored procedure for this.

Thanks,
Viprat Shah

请看看@ 此讨论 [ ^ ]

谢谢
-Amit Gajjar

Hi,

Please have a look @ this Discussion[^]

Thanks
-Amit Gajjar

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