使用*ngFor作用域以外的*ngFor数据

Question

下面是我想要解决的一个示例问题。你的帮助会很感激的。非常感谢!

<div>
  <div>
    <!-- is it possible to put the item.preview here?
        It is outside of *ngFor
    -->
  </div>
  <div *ngFor="let item of items">
      <img [src]="item.cover" alt="item.name">
  </div>
</div>

Answer 1

没有一种方法可以直接显示*ngFor之外的一项，除非您将其中一项设置为变量。通常，这将基于某些事件(e.x )。单击()、mouseover()等.)

下面是一个示例，显示用户单击图像的常见模式，这将设置另一个变量，然后根据需要在组件上的任何其他位置显示该变量。

下面是一个工作柱塞：https://plnkr.co/edit/TzBjhisaPCD2pznb10B0?p=preview

import {Component, NgModule, VERSION, OnInit, Input} from '@angular/core'
import {BrowserModule} from '@angular/platform-browser'

interface Item {
  id: number;
  name: string;
  covor: string
}

@Component({
  selector: 'my-app',
  template: `
    <div>
      <h2>Hello {{name}}</h2>
    </div>
  <div>
    <div>
      {{selectedItem | json}}
    </div>
    <div *ngFor="let item of items">
        <img [src]="item.cover" alt="item.name" (click)="selectItem(item)">
    </div>
  </div>
  `,
})
export class App implements OnInit {
  name:string;

  // This is an input just to show that this might be where the data comes from
  // otherwise call a service to set the data initially
  @Input() items: Item[] = [
    {id: 1, name: 'test', cover: 'https://i.vimeocdn.com/portrait/58832_300x300'},
    {id: 2, name: 'test2', cover: 'https://lh4.ggpht.com/wKrDLLmmxjfRG2-E-k5L5BUuHWpCOe4lWRF7oVs1Gzdn5e5yvr8fj-ORTlBF43U47yI=w300'},
  ];
  selectedItem: Item;

  constructor() {
    this.name = `Angular! v${VERSION.full}`
  }

  ngOnInit() {
    // you can init your item here
    if(this.items.length > 0) {
      this.selectedItem = this.items[0];
    }
  }

  selectItem(item: Item) {
    this.selectedItem = item;
  }
}

@NgModule({
  imports: [ BrowserModule ],
  declarations: [ App ],
  bootstrap: [ App ]
})
export class AppModule {}