当前位置:Gxlcms > JavaScript > Angular怎样向组件输入ngForOf

Angular怎样向组件输入ngForOf

时间:2021-07-01 10:21:17 帮助过:8人阅读

这次给大家带来Angular怎样向组件输入ngForOf,Angular向组件输入ngForOf的注意事项有哪些,下面就是实战案例,一起来看一下。

现在,我们写一个组件puppiesListCmp,用于显示小狗狗的列表:

//puppies-list.component.ts
@Component({
 selector: 'puppies-list',
 template: `
  <p *ngFor="let puppy of puppies">
   <span>{{puppy.name}}</span>
   <span>{{puppy.age}}</span>
   <span>{{puppy.color}}</span>
  </p>
`
})
export class puppiesListCmp{
 @Input() puppies: Puppy[];
}
interface Puppy {
 name: string,
 age: number,
 color: string
}

然后这样使用:

//app.component.ts
@Component({
 selector: 'my-app',
 template: `
  <puppies-list [puppies]="puppies"></puppies-list>
`
})
export class App{
 puppies = [
  {
   name: "sam",
   age: 0.6,
   color: "yellow"
  },
  {
   name: "bingo",
   age: 1.5,
   color: "black"
  }
 ]
}

效果就行这样:

但是,我希望我们的puppiesListCmp组件可以满足不同的需求,比如在数据不变的情况下只显示小狗狗的name和color,就像这样:

这就是本文的重点了。我们需要实现用户自定义模板!

现在我们不写死组件的模板了,而是让用户从外部输入!

首先,我们的组件模板:

<p *ngFor="let puppy of puppies">
   <span>{{puppy.name}}</span>
   <span>{{puppy.age}}</span>
   <span>{{puppy.color}}</span>
</p>

等价于:

<ng-template ngFor let-puppy [ngForOf]="puppies">
   <p>
    <span>{{puppy.name}}</span>
    <span>{{puppy.age}}</span>
    <span>{{puppy.color}}</span>
   </p>
</ng-template>

然后,用@ContentChild(关于@ContentChild可以查看这里,需FQ)获取到外部(相对puppiesListCmp组件而言)自定义模板,并赋给ngForTemplate。也就是说,这部分:

<p>
  <span>{{puppy.name}}</span>
  <span>{{puppy.age}}</span>
  <span>{{puppy.color}}</span>
</p>

不再像之前那样写死在组件里了,而是由使用者在父组件中自定义,然后利用Angular的内容投射(Content Projection),投射到puppiesListCmp组件里面。就像这样:

//puppies-list.component.ts
import { Component, Input, ContentChild, TemplateRef } from '@angular/core';
import { NgForOfContext } from '@angular/common';
@Component({
 selector: 'puppies-list',
 template: `
<ng-template ngFor let-puppy [ngForOf]="puppies" [ngForTemplate]="tpl"></ng-template>
`
})
export class puppiesListCmp{
 @Input() puppies: Puppy[];
 @ContentChild(TemplateRef) tpl: TemplateRef<NgForOfContext<Puppy>>
}
interface Puppy {
 name: string,
 age: number,
 color: string
}

这样我们的组件就算完成了。然后我们使用它:

//app.component.ts
@Component({
 selector: 'my-app',
 template: `
<puppies-list [puppies]="puppies">
 <ng-template let-puppy>
  <p>
   <span>{{puppy.name}}</span>
   <span>{{puppy.age}}</span>
   <span>{{puppy.color}}</span>
  </p>
 </ng-template>
</puppies-list>
`
})

效果还是一样的:

如果我们只要显示小狗狗的name和color,只要这样写就好了:

//app.component.ts
@Component({
 selector: 'my-app',
 template: `
<puppies-list [puppies]="puppies">
 <ng-template let-puppy>
  <p>
   <span>{{puppy.name}}</span>
   <span>{{puppy.color}}</span>
  </p>
 </ng-template>
</puppies-list>
`
})

效果就像这样:

这样的组件很灵活,想要什么样的效果都可以定制,这就实现了组件的复用。

相信看了本文案例你已经掌握了方法,更多精彩请关注Gxl网其它相关文章!

推荐阅读:

vue项目怎样通过百度的BAE发布

为什么vue2中不能使用axios http请求

以上就是Angular怎样向组件输入ngForOf的详细内容,更多请关注Gxl网其它相关文章!

人气教程排行