Question

我想从另一个List中的对象列表中仅选择id： https://dotnetfiddle.net/Leu1AD

我只需要使用linq Select或SelectMany：

[
  {
    "Id":1,
    "Employess":[
      {
        "Id":1,
        "FirstName":"a",
        "LastName":"b"
      },
      {
        "Id":2,
        "FirstName":"c",
        "LastName":"d"
      }
    ]
  },
  {
    "Id":2,
    "Employess":[
      {
        "Id":3,
        "FirstName":"e",
        "LastName":"f"
      },
      {
        "Id":4,
        "FirstName":"g",
        "LastName":"h"
      }
    ]
  }
]

目前我得到以下结果：

[
  {
    "Id":1,
    "Employess":[
      {
        "Id":1
      },
      {
        "Id":2
      }
    ]
  },
  {
    "Id":2,
    "Employess":[
      {
        "Id":3
      },
      {
        "Id":4
      }
    ]
  }
]

但我需要这个结果：

import {provideRouter, RouterConfig} from '@angular/router';
import { AdminpanelComponent } from './components/adminpanel/adminpanel.component';
import { LoginComponent } from './components/login/login.component';

export const AppRoutes: any = [
    { path: '', component: 'LoginComponent'},
    { path: 'login', component: LoginComponent },
    { path: 'admin', component: AdminpanelComponent },
    { path: '**', component: LoginComponent }
];

export const AppComponents: any = [
    LoginComponent,
    AdminpanelComponent
];

你有什么想法怎么做？

Answer 1

将结果作为所需格式的一种方法是

var obj = offices.Select(p => new {Id = p.Id, Employess = p.Employess.Select(y=> new {y.Id})}).ToList();

结束为

[{"Id":1,"Employess":[{"Id":1},{"Id":2}]},{"Id":2,"Employess":[{"Id":3},{"Id":4}]}]

Answer 2

您需要第二个Select仅选择员工Id。

var obj = offices.Select(o => new {Id = o.Id, Employess = o.Employess.Select(e => new { Id = e.Id })});

Answer 3

改变你的行

var obj = offices.Select(p => new {Id = p.Id, Employess = p.Employess}).ToList();

到

var obj = offices.Select(p => new {Id = p.Id, Employess = p.Employess.Select(x=>new{Id=x.Id})}).ToList();

Answer 4

要取代预期结果：

Employess = p.Employess

使用

Employess = p.Employess.Select(e => new { e.Id })

最后你有这个LINQ语句：

var obj = offices.Select(p => new {Id = p.Id, Employess = p.Employess.Select(e => new { e.Id })}).ToList();

如果列表中有List，如何仅使用linq选择Id

4 个答案: