如何使用 LINQ Contains(string[]) 而不是 Contains(string) [英] How do I use LINQ Contains(string[]) instead of Contains(string)

问题描述

我有一个大问题.

我有一个 linq 查询，它看起来像这样:

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

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

string[] 数组的值将是类似 (1,45,20,10,etc...) 的数字

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

.Contains 的默认值是 .Contains(string).

我需要它来代替:.Contains(string[])...

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

一位用户建议为 string[] 编写一个扩展类.我想学习如何学习，但有人愿意为我指明正确的方向吗?

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?

uid 也将是一个数字.这就是它被转换为字符串的原因.

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

帮助任何人?

推荐答案

spoulson 几乎正确，但您需要从 string[]List> 首先.实际上，如果 uid 也是 int，则 List 会更好.List 支持 Contains().执行 uid.ToString().Contains(string[]) 将意味着 uid 作为字符串包含数组的所有值作为子字符串???即使您确实编写了扩展方法，它的意义也是错误的.

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.

除非您像 Mitch Wheat 演示的那样更改它并为 string[] 编写它，否则您只能跳过转换步骤.

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.

[结束]

这就是您想要的，如果您不使用扩展方法(除非您已经将潜在的 uid 集合作为整数 - 则只需使用 List() 代替).这使用了链式方法语法，我认为它更简洁，并且转换为 int 以确保查询可用于更多提供程序.

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));

这篇关于如何使用 LINQ Contains(string[]) 而不是 Contains(string)的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持IT屋！