實體框架 - 排除值列表

當通過實體框架查詢數據庫時，是否有排除對象屬性值列表的方法？實體框架 - 排除值列表

我試圖滑頭拉這個數字：

List<String> StringList = new List<String>(); 
StringList.Add("ya_mama"); 
StringList.Add("has"); 
StringList.Add("fleas"); 

servicesEntities context = new servicesEntities(); 
var NoFleasQuery = (from x in context.person 
        where !StringList.Any(y => y.CompareTo(x.the_string_I_dont_want_it_to_be) == 0) // <--- the part where I thought I was slick 
        select x);

它編譯，但之後，我跑了它，它給了我這個錯誤：

Unable to create a constant value of type 'Closure type'. Only primitive types ('such as Int32, String, and Guid') are supported in this context.

「閉合型」？我的關閉如何！實體框架......你傷了我的心。

來源

2009-11-16 Chris Dutrow

什麼步驟呢？

var NoFleasQuery = (from x in context.person 
         where !StringList.Any(y => x.the_string_I_dont_want_it_to_be == y) 
         select x);

它適用於我。但是生成的SQL相當糟糕：

SELECT 
1 AS [C1], 
[Extent1].[Id] AS [Id], 
[Extent1].[Name] AS [Name], 
[Extent1].[Address_Id] AS [Address_Id] 
FROM [dbo].[Person] AS [Extent1] 
WHERE NOT EXISTS (SELECT 
    1 AS [C1] 
    FROM (SELECT 
     N'John Doe' AS [C1] 
     FROM (SELECT 1 AS X) AS [SingleRowTable1] 
    UNION ALL 
     SELECT 
     N'Jack Black' AS [C1] 
     FROM (SELECT 1 AS X) AS [SingleRowTable2]) AS [UnionAll1] 
    WHERE [Extent1].[Name] = [UnionAll1].[C1] 
)

它建立一個子查詢這是其他子查詢的聯合，而不是使用「NOT IN」 ......也許不是很有效！

來源

2010-04-07 00:41:27

試試這個：

where !StringList.Contains(x.the_string_I_dont_want_it_to_be)

來源

2009-11-16 09:18:45 Konamiman

它給了我這個數字： LINQ to Entities不識別方法'Boolean Contains（System.String）'方法，並且這個方法不能被轉換成存儲表達式。 – 2009-11-16 09:27:52

實體框架 - 排除值列表

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