我有一個簡單的Angular 2服務調用本地JSON文件。我可以在general.service.ts的.map函數中將對象傳遞給console.log。但是,由於異步調用的性質,我似乎無法從對象中打印出單個鍵或值。這是我的代碼。顯示來自JSON的數據使用Angular 2 - Observable和異步
我知道我需要包含* ngIf,因爲它是異步的。然而,即使我已經使用了ngIf與 'generalInfo' 它引用component.ts
general.service.ts
import { Injectable } from '@angular/core';
import { Http, Response } from '@angular/http';
import { Observable } from 'rxjs/Observable';
import 'rxjs/add/operator/catch';
import 'rxjs/add/operator/map';
import { General } from '../interfaces/general.interface'
@Injectable()
export class GeneralService {
private dataAPI = '../../assets/api.json';
constructor(private http: Http) {
}
getGeneralData() : Observable<General> {
return this.http.get(this.dataAPI)
.map((res:Response) => { res.json(); console.log(res.json())})
.catch((error:any) => Observable.throw(error.json().error || 'Server error'));
}
}
header.component.ts
import { Component, OnInit, DoCheck } from '@angular/core';
import 'rxjs/add/operator/map';
import { GeneralService } from '../../services/general.service';
@Component({
selector: 'header',
templateUrl: `./header.component.html`
})
export class headerComponent implements OnInit{
public generalInfo : any;
public name : string;
constructor(
private headerblock: GeneralService
) {}
//Local Properties
header;
loadHeader() {
this.headerblock.getGeneralData()
.subscribe(
generalInfo => {
this.generalInfo = generalInfo;
this.name = this.generalInfo.name
},
err => {
console.log(err);
}
);
}
ngOnInit() {
this.loadHeader();
}
}
header.component .html
<div class="container">
<div *ngIf="generalInfo">
{{name}}
</div>
</div>
雖然此代碼 - 它不會進入if狀態NT。我不知道爲什麼這不起作用?
你在哪裏指定'name'? – echonax
@echonax我試圖將它分配在.subscribe,generalInfo函數中 –
您將'generalInfo'分配給'this.generalInfo',但是'name'分配給了什麼? – echonax