我试图在其 View 呈现之前设置其父组件的子组件属性。
现在我在父组件中使用 ViewChildren 装饰器,但在这种情况下为时已晚,因为 subview 必须使用来自父组件的数据。
所以网格类持有网格对象的完整引用,我想从 grid-header 绑定(bind)到 grid-header-item。
根 html:
<grid-header [grid]="grid" [ngClass.xs]="{'search-open': grid.searchToggle, 'mobile-header': true}">
<grid-header-item fxFlex="75px" name="Level"></grid-header-item>
<grid-header-item fxFlex name="Type"></grid-header-item>
<grid-header-item fxFlex name="Stats"></grid-header-item>
</grid-header>
父组件:
import { Component, ViewChildren, forwardRef, Input, OnInit, AfterViewInit, OnDestroy } from '@angular/core';
import {
StorageService,
} from '../../_shared';
import {
GridHeaderItemComponent,
} from './';
@Component({
selector: 'grid-header',
templateUrl: './grid-header.component.html',
styleUrls: ['./grid-header.component.scss'],
host: {'fxLayout': 'row'}
})
export class GridHeaderComponent implements OnInit, AfterViewInit {
constructor(storage: StorageService) {}
@Input() grid = null;
@ViewChildren(forwardRef(() => GridHeaderItemComponent)) private headerItem;
public ngOnInit() {
}
public ngAfterViewInit() {
console.log(this.headerItem);
setTimeout(() => {
this.headerItem.grid = this.grid;
}, 0);
}
}
子组件:
import { Component, HostBinding, Input, OnInit, OnDestroy } from '@angular/core';
import {
StorageService,
} from '../../_shared';
@Component({
selector: 'grid-header-item',
templateUrl: './grid-header-item.component.html',
styleUrls: ['./grid-header-item.component.scss'],
host: {
}
})
export class GridHeaderItemComponent implements OnInit {
public grid;
constructor(storage: StorageService) {}
@Input() name: string = '';
public ngOnInit() {
console.log(this.name);
}
public ngOnDestroy() {
// this.storage.unsubscribeAll(this.class);
}
}
子组件 html:
<span class="item" (click)="grid.onSortBy(name);">
{{name}} <span *ngIf="grid.sort == name" class="fa" [ngClass]="grid.getDirection(name)"></span>
</span>
我知道,如果我将 [grid]="grid"添加到 grid-header-item 元素,它会起作用,但我认为这是一种开销,因为所有 grid-header 子元素都必须获得此引用,所以这是多余的.
<grid-header [grid]="grid" [ngClass.xs]="{'search-open': grid.searchToggle, 'mobile-header': true}">
<grid-header-item fxFlex="75px" [grid]="grid" name="Level"></grid-header-item>
<grid-header-item fxFlex [grid]="grid" name="Type"></grid-header-item>
<grid-header-item fxFlex [grid]="grid" name="Stats"></grid-header-item>
</grid-header>
最佳答案
由于 angular2 有基于组件树的依赖注入(inject)系统,我们可以简单地在子组件中注入(inject)父组件实例:
grid-header.component.ts
export class GridHeaderItemComponent implements OnInit {
public grid;
@Input() name: string = '';
constructor(private parent: GridHeaderComponent) { }
然后将 parent.grid
属性分配给 ngOnInit 中的本地 grid
属性
grid-header.component.ts
public ngOnInit() {
this.grid = this.parent.grid;
}
您还可以在 Plunker Example 中看到它的实际效果
关于javascript - 在呈现 View 之前从父级设置子组件属性,我们在Stack Overflow上找到一个类似的问题: https://stackoverflow.com/questions/44503250/