Linq返回特定类型 [英] Linq returning specific type

问题描述

如何在Linq查询中返回特定类型?我知道您可以使用ToList()返回特定对象的列表，但是如何返回非列表?

How do you return a specific type in a Linq query? I know you can use ToList() to return a list of specific objects but how do you return a non list?

MyObj x = from x in list where x.id == 99 select x;

推荐答案

MyObj x = list.FirstOrDefault(i=>i.id == 99);

您可以使用

替代IEnumerable方法来返回单个项目:

Alternative IEnumerable methods you can use to return a single item:

• list.Single(i=>i.id == 99):如果未找到匹配项或找到多个匹配项，则会引发异常.
• list.SingleOrDefault(i=>i.id == 99):如果未找到匹配项，则返回null；如果发现多个匹配项，则引发异常.
• list.First(i=>i.id == 99):如果未找到匹配项，则引发异常.如果找到多个匹配项，则返回列表中的第一项.
• list.FirstOrDefault(i=>i.id == 99):如果未找到匹配项，则返回null.如果找到多个匹配项，则返回列表中的第一项.

• list.Single(i=>i.id == 99): throws an exception if no matches are found or multiple matches are found.
• list.SingleOrDefault(i=>i.id == 99): returns null if no matches are found, throws an exception if multiple matches are found.
• list.First(i=>i.id == 99): throws an exception if no matches are found. If multiple matches are found, returns the first item in the list.
• list.FirstOrDefault(i=>i.id == 99): returns null if no matches are found. If multiple matches are found, returns the first item in the list.

这篇关于Linq返回特定类型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！