[英]No provider for Http! - Angular 4 + Rails 5 API
我已经按照本教程进行操作 ,但是很难实现。
我正在使用Angular 4.2.4。
[Error] ERROR
Error: No provider for Http!
injectionError — core.es5.js:1169
...
View_AppComponent_Host_0 (AppComponent_Host.ngfactory.js:4)
...
据我所知,自从编写本教程以来,Angular已经改变了一些内容,包括替换它:
import { Http } from '@angular/http';
有了这个:
import { HttpModule } from '@angular/http';
我试过这个并将HttpModule
添加到`app.module.ts中的imports
数组中。
app.component.ts
import { Component } from '@angular/core';
import { HttpModule } from '@angular/http';
@Component({
selector: 'app-root',
templateUrl: './app.component.html',
styleUrls: ['./app.component.css']
})
export class AppComponent {
title = 'app';
books;
constructor(private http: Http) {
http.get('http://localhost:3000/books.json')
.subscribe(res => this.books = res.json());
}
}
app.module.ts
import { BrowserModule } from '@angular/platform-browser';
import { NgModule } from '@angular/core';
import { AppComponent } from './app.component';
@NgModule({
declarations: [
AppComponent
],
imports: [
BrowserModule,
HttpModule
],
providers: [],
bootstrap: [AppComponent]
})
export class AppModule { }
任何建议将不胜感激。
谢谢!
您应该从AppComponent
@angular/http
导入Http
提供程序,并将HttpModule
添加到AppModule
的imports数组中:
AppComponent
import { Component } from '@angular/core';
import { Http } from '@angular/http';
@Component({
selector: 'app-root',
templateUrl: './app.component.html',
styleUrls: ['./app.component.css']
})
export class AppComponent {
title = 'app';
books;
constructor(private http: Http) {
http.get('http://localhost:3000/books.json')
.subscribe(res => this.books = res.json());
}
}
的AppModule
import { BrowserModule } from '@angular/platform-browser';
import { NgModule } from '@angular/core';
import { HttpModule } from '@angular/http';
import { AppComponent } from './app.component';
@NgModule({
declarations: [
AppComponent
],
imports: [
BrowserModule,
AppModule,
HttpModule
],
providers: [],
bootstrap: [AppComponent]
})
export class AppModule { }
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