Welcome to OStack Knowledge Sharing Community for programmer and developer-Open, Learning and Share
Welcome To Ask or Share your Answers For Others

Categories

0 votes
747 views
in Technique[技术] by (71.8m points)

angular - What is data-bound properties?

I am trying to understand OnInit functionality in angular2 and read the documentation:

Description

Implement this interface to execute custom initialization logic after your directive's data-bound properties have been initialized.

ngOnInit is called right after the directive's data-bound properties have been checked for the first time, and before any of its children have been checked. It is invoked only once when the directive is instantiated.

I do not understand directive's data-bound properties what does it mean?

See Question&Answers more detail:os

与恶龙缠斗过久,自身亦成为恶龙;凝视深渊过久,深渊将回以凝视…
Welcome To Ask or Share your Answers For Others

1 Answer

0 votes
by (71.8m points)

When you have a component

@Component({
  selector: 'my-component'
})
class MyComponent {
  @Input() name:string;

  ngOnChanges(changes) {
  }

  ngOnInit() {
  }
}

you can use it like

<my-component [name]="somePropInParent"></my-component>

This make name a data-bound property.

When the value of somePropInParent was changed, Angulars change detection updates name and calls ngOnChanges()

After ngOnChanges() was called the first time, ngOnInit() is called once, to indicate that initial bindings ([name]="somePropInParent") were resolved and applied.

For more details see https://angular.io/docs/ts/latest/cookbook/component-communication.html


与恶龙缠斗过久,自身亦成为恶龙;凝视深渊过久,深渊将回以凝视…
Welcome to OStack Knowledge Sharing Community for programmer and developer-Open, Learning and Share
Click Here to Ask a Question

...