如何做一个＆QUOT;在＆QUOT;查询实体框架？ [英] How to do an "in" query in entity framework?

问题描述

我如何做一个选择在LINQ to实体选择从列表中键的行？事情是这样的：

How can I do a select in linq to entities to select rows with keys from a list? Something like this:

var orderKeys = new int[] { 1, 12, 306, 284, 50047};
var orders = (from order in context.Orders 
              where (order.Key in orderKeys) 
              select order).ToList();
Assert.AreEqual(orderKeys.Count, orders.Count);

我尝试使用的包含的中提到的一些问题的答案，但它不工作，并抛出这个异常的方法：

I tried using the Contains method as mentioned in some of the answers but it does not work and throws this exception:

LINQ到实体不能识别方法布尔ContainsInt32的方法，而这种方法不能被翻译成店前pression。的

推荐答案

试试这个：

Try this:

var orderKeys = new int[] { 1, 12, 306, 284, 50047};
var orders = (from order in context.Orders 
              where orderKeys.Contains(order.Key);
              select order).ToList();
Assert.AreEqual(orderKeys.Count, orders.Count);

修改我已经找到了一些解决方法针对此问题 - 请<一href="http://social.msdn.microsoft.com/forums/en-US/adodotnetentityframework/thread/095745fe-dcf0-4142-b684-b7e4a1ab59f0/">WHERE IN子句：

I have found some workarounds for this issue - please see WHERE IN clause?:

实体框架不   目前支持集合值   参数（在'statusesToFind'你   例）。要解决此   限制，您可以手动   构造赋予了一个前pression   使用下列值序列   实用方法：

The Entity Framework does not currently support collection-valued parameters ('statusesToFind' in your example). To work around this restriction, you can manually construct an expression given a sequence of values using the following utility method:

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