Angular 认购';不可分配给类型
让服务在页面上显示结果时遇到问题。错误是Subscripting方法返回一个订阅类型,而我一直在尝试将其获取到products数组中。这些产品位于json文件中 设置: 我正在通过一个教程学习Angular 2。本教程已经过时,我正在使用angular的最新版本(ng-v=@angular/cli:1.4.2)。我使用ng new和ng generate设置应用程序 产品列表.component.tsAngular 认购';不可分配给类型,angular,observable,Angular,Observable,让服务在页面上显示结果时遇到问题。错误是Subscripting方法返回一个订阅类型,而我一直在尝试将其获取到products数组中。这些产品位于json文件中 设置: 我正在通过一个教程学习Angular 2。本教程已经过时,我正在使用angular的最新版本(ng-v=@angular/cli:1.4.2)。我使用ng new和ng generate设置应用程序 产品列表.component.ts export class ProductListComponent implements On
export class ProductListComponent implements OnInit {
pageTitle = 'Product List';
imageWidth = 50;
imageMargin = 2;
showImage = false;
listFilter = '';
products: IProductList[];
subscription: Subscription;
errorMessage = '';
constructor(private _productListService: ProductListService) {
}
ngOnInit() {
**// ERROR - 'Subscription' is not assignable to type 'IProductList[]'**
this.products = this._productListService.getProducts() // ******** ERROR ******
.subscribe(
products => this.products = products,
error => this.errorMessage = <any>error);
}
import { Injectable } from '@angular/core';
import { Http, Response } from '@angular/http';
import { Observable } from 'rxjs/Observable';
import { IProductList } from './product-list';
@Injectable()
export class ProductListService {
private _productListUrl = 'api/product-list/product-list.json';
constructor(private _http: Http) { }
getProducts(): Observable<IProductList[]> {
return this._http.get(this._productListUrl)
.map((response: Response) => <IProductList[]>response.json())
.do(data => console.log('All: ' + JSON.stringify(data)))
.catch(this.handleError);
}
private handleError(error: Response) {
console.error(error);
return Observable.throw(error.json().error || 'Server Error');
}
}
导出类ProductListComponent实现OnInit{
pageTitle='产品列表';
图像宽度=50;
图像边缘=2;
showImage=false;
listFilter='';
产品:IPProductList[];
认购:认购;
errorMessage='';
构造函数(private\u productListService:productListService){
}
恩戈尼尼特(){
**//错误-“订阅”不可分配给类型“IPProductList[]”**
this.products=this.\u productListService.getProducts()/*******错误******
.订阅(
products=>this.products=products,
error=>this.errorMessage=error);
}
产品列表.服务.ts
export class ProductListComponent implements OnInit {
pageTitle = 'Product List';
imageWidth = 50;
imageMargin = 2;
showImage = false;
listFilter = '';
products: IProductList[];
subscription: Subscription;
errorMessage = '';
constructor(private _productListService: ProductListService) {
}
ngOnInit() {
**// ERROR - 'Subscription' is not assignable to type 'IProductList[]'**
this.products = this._productListService.getProducts() // ******** ERROR ******
.subscribe(
products => this.products = products,
error => this.errorMessage = <any>error);
}
import { Injectable } from '@angular/core';
import { Http, Response } from '@angular/http';
import { Observable } from 'rxjs/Observable';
import { IProductList } from './product-list';
@Injectable()
export class ProductListService {
private _productListUrl = 'api/product-list/product-list.json';
constructor(private _http: Http) { }
getProducts(): Observable<IProductList[]> {
return this._http.get(this._productListUrl)
.map((response: Response) => <IProductList[]>response.json())
.do(data => console.log('All: ' + JSON.stringify(data)))
.catch(this.handleError);
}
private handleError(error: Response) {
console.error(error);
return Observable.throw(error.json().error || 'Server Error');
}
}
从'@angular/core'导入{Injectable};
从'@angular/Http'导入{Http,Response};
从“rxjs/Observable”导入{Observable};
从“./产品列表”导入{IPProductList};
@可注射()
导出类ProductListService{
private _productListUrl='api/product list/product list.json';
构造函数(私有http:http){}
getProducts():可观察{
返回此.\u http.get(此.\u productListUrl)
.map((response:response)=>response.json())
.do(data=>console.log('All:'+JSON.stringify(data)))
.接住(这个.把手错误);
}
私有句柄错误(错误:响应){
控制台错误(error);
返回Observable.throw(error.json().error | |'Server error');
}
}
产品列表.component.html
<tr *ngFor='let product of products | async | productFilter: listFilter' >
<td>
<img *ngIf='showImage' [src]='product.imageUrl' [title]='product.productName' [style.width.px]='imageWidth' [style.marging.px]='imageMargin'>
</td>
<td>{{product.productName}}</td>
<td>{{product.productCode | lowercase }}</td>
<td>{{product.releaseDate}}</td>
<td>{{product.price | currency:'USD':true:'1.2-2' }}</td>
<td><app-ai-star [rating] = 'product.starRating'
(ratingClicked)='onRatingClicked($event)'></app-ai-star></td>
</tr>
{{product.productName}
{{product.productCode}小写}
{{product.releaseDate}
{{product.price}货币:'USD':真:'1.2-2'}
问题是您想订阅getProducts()
调用
ngOnInit() {
this.subscription = this._productListService.getProducts() // subscription created here
.subscribe(
products => this.products = products, // value applied to products here
error => this.errorMessage = <any>error);
}
ngOnInit(){
this.subscription=this.\u productListService.getProducts()//在此处创建的订阅
.订阅(
products=>this.products=products,//此处应用于产品的值
error=>this.errorMessage=error);
}
此.products的值在subscribe()
中分配。您可以忽略返回的订阅对象,如下面的代码片段所示
ngOnInit() {
this._productListService.getProducts()
.subscribe(
products => this.products = products,
error => this.errorMessage = <any>error);
}
ngOnInit(){
这是.\u productListService.getProducts()
.订阅(
products=>this.products=products,
error=>this.errorMessage=error);
}