Javascript 角度2:注入服务
我开始学安圭拉,但是。。我试图在我的组件中创建服务和导入,但出现以下错误: 错误TS2339:类型上不存在属性“commentService” “CommentsComponent” comment.service.tsJavascript 角度2:注入服务,javascript,service,angular,inject,Javascript,Service,Angular,Inject,我开始学安圭拉,但是。。我试图在我的组件中创建服务和导入,但出现以下错误: 错误TS2339:类型上不存在属性“commentService” “CommentsComponent” comment.service.ts import { Injectable } from '@angular/core'; @Injectable() export class CommentService { testfunction() { return 'valoare';
import { Injectable } from '@angular/core';
@Injectable()
export class CommentService {
testfunction() {
return 'valoare';
}
}
import { Component, OnInit } from '@angular/core';
import { CommentService } from '../services/comment.service';
@Component({
template: 'dadada',
providers: [CommentService]
})
export class CommentsComponent implements OnInit {
construct(commentService: CommentService) {
}
ngOnInit() {
console.log( this.commentService.testfunction() );
}
}
import { Component } from '@angular/core';
import { ROUTER_DIRECTIVES } from '@angular/router';
@Component({
selector: '[web-application]',
templateUrl: 'template/home',
directives: [ROUTER_DIRECTIVES]
})
export class AppComponent { }
import { provideRouter, RouterConfig } from '@angular/router';
import { CommentsComponent } from './components/comments.component';
import { HomeComponent } from './components/home.component';
const routes: RouterConfig = [
{ path: '', component: HomeComponent },
{ path: 'comments', component: CommentsComponent }
];
export const appRouterProviders = [
provideRouter(routes)
];
import { bootstrap } from '@angular/platform-browser-dynamic';
import { AppComponent } from './components/app.component';
import { appRouterProviders } from './app.routes';
import { CommentService } from './services/comment.service'
bootstrap(AppComponent, [
appRouterProviders,
CommentService
])
.catch(err => console.error(err));
comments.component.ts
import { Injectable } from '@angular/core';
@Injectable()
export class CommentService {
testfunction() {
return 'valoare';
}
}
import { Component, OnInit } from '@angular/core';
import { CommentService } from '../services/comment.service';
@Component({
template: 'dadada',
providers: [CommentService]
})
export class CommentsComponent implements OnInit {
construct(commentService: CommentService) {
}
ngOnInit() {
console.log( this.commentService.testfunction() );
}
}
import { Component } from '@angular/core';
import { ROUTER_DIRECTIVES } from '@angular/router';
@Component({
selector: '[web-application]',
templateUrl: 'template/home',
directives: [ROUTER_DIRECTIVES]
})
export class AppComponent { }
import { provideRouter, RouterConfig } from '@angular/router';
import { CommentsComponent } from './components/comments.component';
import { HomeComponent } from './components/home.component';
const routes: RouterConfig = [
{ path: '', component: HomeComponent },
{ path: 'comments', component: CommentsComponent }
];
export const appRouterProviders = [
provideRouter(routes)
];
import { bootstrap } from '@angular/platform-browser-dynamic';
import { AppComponent } from './components/app.component';
import { appRouterProviders } from './app.routes';
import { CommentService } from './services/comment.service'
bootstrap(AppComponent, [
appRouterProviders,
CommentService
])
.catch(err => console.error(err));
应用程序组件.ts
import { Injectable } from '@angular/core';
@Injectable()
export class CommentService {
testfunction() {
return 'valoare';
}
}
import { Component, OnInit } from '@angular/core';
import { CommentService } from '../services/comment.service';
@Component({
template: 'dadada',
providers: [CommentService]
})
export class CommentsComponent implements OnInit {
construct(commentService: CommentService) {
}
ngOnInit() {
console.log( this.commentService.testfunction() );
}
}
import { Component } from '@angular/core';
import { ROUTER_DIRECTIVES } from '@angular/router';
@Component({
selector: '[web-application]',
templateUrl: 'template/home',
directives: [ROUTER_DIRECTIVES]
})
export class AppComponent { }
import { provideRouter, RouterConfig } from '@angular/router';
import { CommentsComponent } from './components/comments.component';
import { HomeComponent } from './components/home.component';
const routes: RouterConfig = [
{ path: '', component: HomeComponent },
{ path: 'comments', component: CommentsComponent }
];
export const appRouterProviders = [
provideRouter(routes)
];
import { bootstrap } from '@angular/platform-browser-dynamic';
import { AppComponent } from './components/app.component';
import { appRouterProviders } from './app.routes';
import { CommentService } from './services/comment.service'
bootstrap(AppComponent, [
appRouterProviders,
CommentService
])
.catch(err => console.error(err));
应用程序路由.ts
import { Injectable } from '@angular/core';
@Injectable()
export class CommentService {
testfunction() {
return 'valoare';
}
}
import { Component, OnInit } from '@angular/core';
import { CommentService } from '../services/comment.service';
@Component({
template: 'dadada',
providers: [CommentService]
})
export class CommentsComponent implements OnInit {
construct(commentService: CommentService) {
}
ngOnInit() {
console.log( this.commentService.testfunction() );
}
}
import { Component } from '@angular/core';
import { ROUTER_DIRECTIVES } from '@angular/router';
@Component({
selector: '[web-application]',
templateUrl: 'template/home',
directives: [ROUTER_DIRECTIVES]
})
export class AppComponent { }
import { provideRouter, RouterConfig } from '@angular/router';
import { CommentsComponent } from './components/comments.component';
import { HomeComponent } from './components/home.component';
const routes: RouterConfig = [
{ path: '', component: HomeComponent },
{ path: 'comments', component: CommentsComponent }
];
export const appRouterProviders = [
provideRouter(routes)
];
import { bootstrap } from '@angular/platform-browser-dynamic';
import { AppComponent } from './components/app.component';
import { appRouterProviders } from './app.routes';
import { CommentService } from './services/comment.service'
bootstrap(AppComponent, [
appRouterProviders,
CommentService
])
.catch(err => console.error(err));
main.ts
import { Injectable } from '@angular/core';
@Injectable()
export class CommentService {
testfunction() {
return 'valoare';
}
}
import { Component, OnInit } from '@angular/core';
import { CommentService } from '../services/comment.service';
@Component({
template: 'dadada',
providers: [CommentService]
})
export class CommentsComponent implements OnInit {
construct(commentService: CommentService) {
}
ngOnInit() {
console.log( this.commentService.testfunction() );
}
}
import { Component } from '@angular/core';
import { ROUTER_DIRECTIVES } from '@angular/router';
@Component({
selector: '[web-application]',
templateUrl: 'template/home',
directives: [ROUTER_DIRECTIVES]
})
export class AppComponent { }
import { provideRouter, RouterConfig } from '@angular/router';
import { CommentsComponent } from './components/comments.component';
import { HomeComponent } from './components/home.component';
const routes: RouterConfig = [
{ path: '', component: HomeComponent },
{ path: 'comments', component: CommentsComponent }
];
export const appRouterProviders = [
provideRouter(routes)
];
import { bootstrap } from '@angular/platform-browser-dynamic';
import { AppComponent } from './components/app.component';
import { appRouterProviders } from './app.routes';
import { CommentService } from './services/comment.service'
bootstrap(AppComponent, [
appRouterProviders,
CommentService
])
.catch(err => console.error(err));
有人知道我为什么不能注入服务吗
export class CommentsComponent implements OnInit {
construct(commentService: CommentService) {
应该是
export class CommentsComponent implements OnInit {
constructor(private /* or public */ commentService: CommentService) {
添加
private
或public
使其成为实例属性,否则它只是一个参数。在注入依赖项时,应提供访问修饰符。
用这个
将参数设为私有 这就解决了问题
@Component({
template: 'dadada',
providers: [CommentService]
})
export class CommentsComponent implements OnInit {
constructor(private _commentService: CommentService) {
}
ngOnInit() {
console.log( this._commentService.testfunction() );
}
}
您可以保留下划线,这只是私有变量的约定。我已经尝试过了,但我得到了这个结论:参数属性只允许在构造函数实现中使用。我明白了。听起来很合理。构造函数应命名为
constructor
,而不是construct
,尽管如此;-)哈哈,同样的问题。我在“constructor”一词中有语法错误。哈哈,同样的问题!我拼错了“constructor”。等等。我又错了一次!:(