我如何使用LINQ包含（字符串[]），而不是包含（字符串） [英] How do I use LINQ Contains(string[]) instead of Contains(string)

问题描述

我得到了一个大问题。

我有一个LINQ查询简单地说是这样的：

I got a linq query to put it simply looks like this:

from xx in table
where xx.uid.ToString().Contains(string[])
select xx

在字符串值[] 阵列会像数字（1,45,20,10，等...）

The values of the string[] array would be numbers like (1,45,20,10,etc...)

为。载默认为。载有（串）。

我需要做的这个代替：。载有（串[]） ...

I need it to do this instead: .Contains(string[])...

编辑：一个用户提出书面延期类的String [] 。我想了解如何操作，但任何一个愿意点我朝着正确的方向吗？

EDIT : One user suggested writing an extension class for string[]. I would like to learn how, but any one willing to point me in the right direction?

编辑：的UID也将是一个数字。这就是为什么它转换为字符串。

EDIT : The uid would also be a number. That's why it is converted to a string.

帮助的人？

推荐答案

spoulson有它近的权利，但你需要创建一个列表＆LT;串＆GT; 从的String [] 第一。其实一个列表与LT; INT＆GT; 会更好，如果uid是也 INT 。 列表＆LT; T＆GT; 支持包含（）。做 uid.ToString（）。包含（字符串[]）将意味着uid作为一个字符串包含所有数组作为一个子字符串的值？即使你没有写扩展方法的它的意义将是错误的。

spoulson has it nearly right, but you need to create a List<string> from string[] first. Actually a List<int> would be better if uid is also int. List<T> supports Contains(). Doing uid.ToString().Contains(string[]) would imply that the uid as a string contains all of the values of the array as a substring??? Even if you did write the extension method the sense of it would be wrong.

除非你周围变化并把它写在的String [] 作为米奇小麦证明，那么你只可以跳过转换步骤。

Unless you changed it around and wrote it for string[] as Mitch Wheat demonstrates, then you'd just be able to skip the conversion step.

[EndEdit中]

下面是你想要什么，如果你不这样做的扩展方法（除非你已经有潜在的UID的集合作为整数 - 那么就使用列表＆LT; INT＆GT;（）代替）。本品采用链式方法的语法，我认为这是更清洁和
并转换为int，以确保该查询可以与多个提供使用。

Here is what you want, if you don't do the extension method (unless you already have the collection of potential uids as ints -- then just use List<int>() instead). This uses the chained method syntax, which I think is cleaner, and does the conversion to int to ensure that the query can be used with more providers.

var uids = arrayofuids.Select(id => int.Parse(id)).ToList();

var selected = table.Where(t => uids.Contains(t.uid));

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