当Observable/subscrption更改属性时,ngOnChanges不会触发

Question

我想要的以后做什么Observable/ subscribe完成.我正在改变方法中的Input属性subscribe( onNext ),但从ngOnChanges不触发.

我应该做些什么呢？

import { Component, EventEmitter, 
  OnInit, AfterViewInit, OnChanges, SimpleChanges,
  Input, Output
} from '@angular/core';

@Component({
  templateUrl: 'myTemplate.html'
    , providers: [ NamesService ]
})

export class MyPage  {
  @Input() names: any[];

  constructor( public namesSvc: NamesService) {}

  ngOnInit() {
    this.getNames$()
  }


  getNames$() : void {
    this.nameService.get().subscribe( 
      (result)=>{
       this.names = result;
       console.log(`getNames$, names=${this.names}`);

       // I could doSomething() here, but it doesn't seem like the correct place
       // doSomething()  

      }
      , error =>  this.errorMessage = <any>error
    )
  }

  ngOnChanges(changes: SimpleChanges) : void {
    // changes.prop contains the old and the new value...
    console.warn(`>>> ngOnChanges triggered`)
    if (changes["names"]) {
      console.warn(`>>> ngOnChanges, names=${changes["names"]}`)
      this.doSomething()
    }
  }

  doSomething(){
    console.log("doing something");
  }
}

Answer 1

这是"按设计"

ngOnChanges()仅在更改检测更新绑定到的时调用@Input().如果从某个地方强制改变输入,则不会调用它.

只需names为每次更新属性时执行的代码创建一个getter/setter.