如何使用*ngFor迭代对象键

Question

我想在Angular 2中使用*ngFor迭代[object object].

问题是对象不是对象数组而是包含更多对象的对象对象.

{

  "data": {
    "id": 834,
    "first_name": "GS",
    "last_name": "Shahid",
    "phone": "03215110224",
    "role": null,
    "email": "test@example.com",
    "picture": **{ <-- I want to get thumb: url but not able to fetch that**
      "url": null,
      "thumb": {
        "url": null
      }
    },
    "address": "Nishtar Colony",
    "city_id": 2,
    "provider": "email",
    "uid": "test@example.com"
  }
}

我知道我们可以使用管道迭代对象,但我们如何能够从对象进一步迭代意味着data-> picture-> thum:url.

Answer 1

Angular 6.0.0

https://github.com/angular/angular/blob/master/CHANGELOG.md#610-beta1-2018-06-13

介绍一个 KeyValuePipe

@Component({
  selector: 'keyvalue-pipe',
  template: `<span>
    <p>Object</p>
    <div *ngFor="let item of object | keyvalue">
      {{item.key}}:{{item.value}}
    </div>
    <p>Map</p>
    <div *ngFor="let item of map | keyvalue">
      {{item.key}}:{{item.value}}
    </div>
  </span>`
})
export class KeyValuePipeComponent {
  object: {[key: number]: string} = {2: 'foo', 1: 'bar'};
  map = new Map([[2, 'foo'], [1, 'bar']]);
}

原版的

你可以使用管道

@Pipe({ name: 'keys',  pure: false })
export class KeysPipe implements PipeTransform {
    transform(value: any, args: any[] = null): any {
        return Object.keys(value)//.map(key => value[key]);
    }
}

<div *ngFor="let key of objs | keys">

另请参见如何使用*ngFor迭代对象键？

Answer 2

我认为最优雅的方法是使用这样的javascript Object.keys:

在Component中将Object传递给模板:

Object = Object;

然后在模板中:

<div *ngFor="let key of Object.keys(objs)">
   my key: {{key}}
   my object {{objs[key] | json}} <!-- hier I could use ngFor again with Object.keys(objs[key]) -->
</div>

Answer 3

循环遍历 Angular HTML 模板中的对象

Angular中引入keyValuePipe：请参考https://angular.io/api/common/KeyValuePipe

快速代码：

<p>Object</p>
    <div *ngFor="let item of object | keyvalue">
      {{item.key}}:{{item.value}}
    </div>
    <p>Map</p>
    <div *ngFor="let item of map | keyvalue">
      {{item.key}}:{{item.value}}
    </div>

Answer 4

您必须创建自定义管道.

import { Injectable, Pipe } from '@angular/core';
@Pipe({
   name: 'keyobject'
})
@Injectable()
export class Keyobject {

transform(value, args:string[]):any {
    let keys = [];
    for (let key in value) {
        keys.push({key: key, value: value[key]});
    }
    return keys;
}}

然后在你的*ngFor中使用它

*ngFor="let item of data | keyobject"

Answer 5

我知道这个问题已经回答，但是我有一个解决方案。

您还可以Object.keys()在中使用*ngFor以获得所需的结果。

我已经在stackblitz上创建了一个演示。我希望这会对您/其他人有所帮助/指导。

代码片段

HTML代码

<div *ngFor="let key of Object.keys(myObj)">
  <p>Key-> {{key}} and value is -> {{myObj[key]}}</p>
</div>

.ts文件代码

Object = Object;

myObj = {
    "id": 834,
    "first_name": "GS",
    "last_name": "Shahid",
    "phone": "1234567890",
    "role": null,
    "email": "test@example.com",
    "picture": {
        "url": null,
        "thumb": {
            "url": null
        }
    },
    "address": "XYZ Colony",
    "city_id": 2,
    "provider": "email",
    "uid": "test@example.com"
}

Answer 6

1.创建自定义管道来获取密钥。

import { Pipe, PipeTransform } from '@angular/core';

@Pipe({
  name: 'keys'
})
export class KeysPipe implements PipeTransform {

  transform(value: any, args?: any): any {
    return Object.keys(value);
  }
}

2. 在角度模板文件中，您可以使用 *ngFor 并迭代您的对象对象

<div class ="test" *ngFor="let key of Obj | keys">
    {{key}}
    {{Obj[key].property}
<div>