我试图建立一个TimelineComponent
,这个想法是我可以写的
<timeline>
<timeline-item-group *ngFor="#group of groups" date="group.date">
<timeline-item *ngFor="#item in group.items">
...do something with item here...
</timeline-item>
<timeline-item-group>
</timeline>
将转换为
<ul class="timeline">
<li class="timeline-item">...group 1 item 1...</li>
<li class="timeline-item">...group 1 item 2...</li>
...
<li class="timeline-separator">...group 1 date...</li>
<li class="timeline-item">...group 2 item 1...</li>
<li class="timeline-item">...group 2 item 2...</li>
...
<li class="timeline-separator">...group 2 date...</li>
</ul
这里是组件的Typescript:
import { Component, Input } from 'angular2/core'
@Component({
selector: 'timeline',
templateUrl: 'app/timeline.component.html',
styleUrls: ['app/timeline.component.css']
})
export class TimelineComponent {
groups: TimelineItemGroupComponent[] = [];
constructor() {
}
addGroup(group: TimelineItemGroupComponent) {
this.groups.push(group);
console.log('item added');
}
}
@Component({
selector: 'timeline-item-group',
templateUrl: 'app/timeline-item-group.component.html',
styleUrls: ['app/timeline-item-group.component.css']
})
export class TimelineItemGroupComponent {
@Input() name: string;
items: TimelineItemComponent[] = [];
constructor(timeline: TimelineComponent) {
timeline.addGroup(this);
}
addItem(item: TimelineItemComponent) {
this.items.push(item);
}
}
@Component({
selector: 'timeline-item',
templateUrl: 'app/timeline-item.component.html',
styleUrls: ['app/timeline-item.component.css']
})
export class TimelineItemComponent {
@Input() title: string;
constructor(timelineGroup: TimelineItemGroupComponent) {
timelineGroup.addItem(this);
}
}
问题是,如何循环群组?如果这只是一个简单的项目清单,我只需写一下
<ul>
<li class="timeline-item" *ngFor="#item of items">...</li>
</ul>
但是还有一个级别要循环(群组),我不想生成额外的标记,例如
<ul>
<div *ngFor="#group of groups">
<li class="timeline-item" *ngFor="#item of group.items">...</li>
<li class="timeline-separator">{{group.date}}</li>
</div>
</ul>
希望我明白我的观点。那么我的选择是什么?
答案 0 :(得分:2)
无法展平嵌套*ngFor
。
在从中生成DOM并使用
之前,先将数据展平<ul>
<ng-container *ngFor="let item of flattenedHeroes trackBy:trackByHeroes">
<li class="timeline-item">...</li>
<li class="timeline-separator" *ngIf="item.isGroup">{{item.date}}</li>
</ng-container>
</ul>
我刚刚发明了isGroup
。这可以是任何允许区分组和项目的东西。