Question

我尝试检测变量子项的变化，但变量更改时ngOnChanges没有触发

@Input() _parent: any;

ngOnChanges(changes: {[propKey: string] : SimpleChange}) { << not fire
  console.log('Change detected:');

  setTimeout(() => {

    if (!_.isEqual(this._parent.curScript, changes['_parent'].currentValue.curScript)) {
      console.log(1);
    }  
  }, 100);
}

我的问题是什么？

Answer 1

如注释中所述，ngOnChanges仅检测输入属性的更改，这些更改在组件组合到另一个组件的模板时传入。生命周期钩子的Angular文档应该具有启发性https://angular.io/guide/lifecycle-hooks#onchanges

Answer 2

。您可以通过ChangeDetectorRef检测更改。你可以像那样使用它

constructor( private dcr: ChangeDetectorRef) {
    }

this.dcr.detectChanges(); // put this line where changes made for example you change `_parent` variable value from parent component you need to put that place. child value changed automatically. does this help

当深度子变化时，ngOnChanges Angular 2不会触发

2 个答案: