C# 在列表中使用 Linq 选择列表
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Using Linq select list inside list
提问by Reno
Using LINQ how to select from a List within a List
使用 LINQ 如何从列表中的列表中进行选择
public class Model
{
public string application { get; set; }
public List<Users> users { get; set; }
}
public class Users
{
public string name { get; set; }
public string surname { get; set; }
}
List<Model> list = new List<Model>();
I need to select list where application = "applicationame" and users where surname = "surname" into one list.
我需要选择列表 where application = "applicationame" 和 users where surname = "surname" 到一个列表中。
采纳答案by Tim Schmelter
If you want to filter the models by applicationnameand the remaining models by surname:
如果您想通过以下方式过滤模型applicationname和其余模型surname：
List<Model> newList = list.Where(m => m.application == "applicationname")
.Select(m => new Model {
application = m.application,
users = m.users.Where(u => u.surname == "surname").ToList()
}).ToList();
As you can see, it needs to create new models and user-lists, hence it is not the most efficient way.
如您所见，它需要创建新模型和用户列表，因此这不是最有效的方法。
If you instead don't want to filter the list of users but filter the models by users with at least one user with a given username, use Any:
如果您不想过滤用户列表，而是按至少有一个用户并具有给定用户名的用户过滤模型，请使用Any：
List<Model> newList = list
.Where(m => m.application == "applicationname"
&& m.users.Any(u => u.surname == "surname"))
.ToList();
回答by Cédric Bignon
You have to use the SelectManyextension method or its equivalent syntax in pure LINQ.
您必须SelectMany在纯 LINQ 中使用扩展方法或其等效语法。
(from model in list
where model.application == "applicationname"
from user in model.users
where user.surname == "surname"
select new { user, model }).ToList();
回答by I4V
list.Where(m => m.application == "applicationName" &&
m.users.Any(u => u.surname=="surname"));
if you want to filterusers as TimSchmelter commented, you can use
如果您想按照 TimSchmelter 的评论过滤用户，您可以使用
list.Where(m => m.application == "applicationName")
.Select(m => new Model
{
application = m.application,
users = m.users.Where(u => u.surname=="surname").ToList()
});
回答by It'sNotALie.
After my previous answer disaster, I'm going to try something else.
在我之前的答案灾难之后，我将尝试其他方法。
List<Model> usrList =
(list.Where(n => n.application == "applicationame").ToList());
usrList.ForEach(n => n.users.RemoveAll(n => n.surname != "surname"));
