我的目录结构如下:
我将父组件(app.component)的一些方法分配给它的实例变量,如下所示:
export class AppComponent implements AfterViewInit, AfterContentInit{
@ViewChild('contentLoginModl') contentLoginModlCon: ElementRef;
@ViewChild('modlSignToApplyTg') modlSignToApplyTg: ElementRef;
@ViewChild('uploadCV') uploadCV: ElementRef;
.....
constructor(){ .... }
.....
ngAfterViewInit() {
this.appState.set('opnLgnAppTmp',this.contentLoginModlCon);
this.appState.set('opnUpldCvAppTmp',this.uploadCV);
this.appState.set('opnLgnBfrAppTmp',this.modlSignToApplyTg);
}
appState(service)是通过所有组件共享的,但是当我在子compinent中调用一个访问parrent视图引用的函数时,它的定义如下:
TypeError: Cannot read property 'open' of undefined
at AppState._state.open (http://localhost:5003/static/main.prod.bundle.js:6:3788)
at AppComponent.opnWithTry (http://localhost:5003/static/main.prod.bundle.js:2:17395)
at AppComponent.opnLgnBfrApp (http://localhost:5003/static/main.prod.bundle.js:2:2714)
at EditProfile.starItm (http://localhost:5003/static/main.prod.bundle.js:7:14899)
at View_EditProfile26.handleEvent_24 (/AppModule/EditProfile/component.ngfactory.js:2700:51)
at HTMLAnchorElement.<anonymous> (http://localhost:5003/static/vendor.prod.bundle.js:27:22958)
at ZoneDelegate.invokeTask (http://localhost:5003/static/polyfills.prod.bundle.js:4:12265)
at Object.onInvokeTask (http://localhost:5003/static/vendor.prod.bundle.js:26:14260)
at ZoneDelegate.invokeTask (http://localhost:5003/static/polyfills.prod.bundle.js:4:12170)
at Zone.runTask (http://localhost:5003/static/polyfills.prod.bundle.js:4:8197)
1 回答
如果您在构造函数中访问子组件中的状态或
ngOnInit()
,那么这是因为尚未执行父项的ngAfterViewInit()
且尚未设置属性 .我建议你使用孩子订阅的observable,并在发出值时得到通知 . 如果您使用
BehaviorSubject
,则在父项发出属性之前或之后订阅子项无关紧要 .另见https://angular.io/docs/ts/latest/cookbook/component-communication.html#!#bidirectional-service