如何将属性从父组件传递到其子组件的类构造函数中Angular 2
?
由于属性可以毫无问题地传递到视图,因此可以解决一半的谜团。
import {Component, View, bootstrap} from 'angular2/angular2';
import {Example} from 'client/example';
@Component({
selector: 'app'
})
@View({
template: `<p>Hello</p>
<example [test]="someAttr"
[hyphenated-test]="someHyphenatedAttr"
[alias-test]="someAlias"></example>
`,
directives: [Example]
})
class App {
constructor() {
this.someAttr = "attribute passsed to component";
this.someHyphenatedAttr = "hyphenated attribute passed to component";
this.someAlias = "attribute passed to component then aliased";
}
}
bootstrap(App);
import {Component, View, Attribute} from 'angular2/angular2';
@Component({
selector: 'example',
properties: ['test', 'hyphenatedTest', 'alias: aliasTest']
})
@View({
template: `
<p>Test: {{test}}</p>
<!-- result: attribute passsed to component -->
<p>Hyphenated: {{hyphenatedTest}}</p>
<!-- result: hyphenated attribute passed to component -->
<p>Aliased: {{alias}}</p>
<!-- result: attribute passed to component then aliased -->
<button (click)="attributeCheck()">What is the value of 'this.test'?</button>
<!-- result: attribute passed to component -->
`
})
/*******************************************************************
* HERE IS THE PROBLEM. How to access the attribute inside the class?
*******************************************************************/
export class Example {
constructor(@Attribute('test') test:string) {
console.log(this.test); // result: undefined
console.log(test); // result: null
}
attributeCheck() {
alert(this.test);
}
}
要重申:
如何访问从父组件传入的子组件类中的属性?
更新至beta.1
您可以为此使用ngOnInit
@Component({
selector: 'example',
inputs: ['test', 'hyphenatedTest', 'alias: aliasTest'],
template: `
<p>Test: {{test}}</p>
<!-- result: attribute passsed to component -->
<p>Hyphenated: {{hyphenatedTest}}</p>
<!-- result: hyphenated attribute passed to component -->
<p>Aliased: {{alias}}</p>
<!-- result: attribute passed to component then aliased -->
<button (click)="attributeCheck()">What is the value of 'this.test'?</button>
<!-- result: attribute passed to component -->
`
})
export class Example {
ngOnInit() {
console.log(this.test);
this.attributeCheck();
}
attributeCheck() {
alert(this.test);
}
}
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