使用LINQ里面选择列表列表 [英] Using Linq select list inside list

问题描述

使用LINQ如何从一个List一个List

Using LINQ how to select from a List within a List

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>();

我需要选择列表，应用程序=applicationame和使用者，其中姓=姓成一个名单。

I need to select list where application = "applicationame" and users where surname = "surname" into one list.

推荐答案

如果您想通过的applicationName 来筛选模型和通过姓其余型号：

If you want to filter the models by applicationname and the remaining models by 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();

正如你所看到的，它需要创造新的模式和用户列表，因此它是不最有效的方法。

As you can see, it needs to create new models and user-lists, hence it is not the most efficient way.

如果您代替不希望过滤用户列表而是通过用户与至少一个用户与给定的用户名筛选模型，用任何：

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:

List<Model> newList = list
    .Where(m => m.application == "applicationname"
            &&  m.users.Any(u => u.surname == "surname"))
    .ToList();

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