小编Faz*_*hid的帖子

我有一个应用程序模块和单个组件应用程序(用于演示我的问题),并收到以下错误:

 Error in ./AppComponent class AppComponent_Host - inline template:0:0 caused by: No provider for UserService! ; Zone: <root> ; Task: Promise.then ; Value:

AppModule的代码:

import { NgModule }       from '@angular/core';
import { BrowserModule }  from '@angular/platform-browser';
import { UserService } from './components/common/userservice';

@NgModule({
    imports: [
    BrowserModule,
],
declarations: [
    AppComponent
],
providers: [UserService],
bootstrap: [AppComponent],
entryComponents: []

})
export class AppModule {
}

我的AppComponent的代码:

import { Component} from '@angular/core';
import { UserService} from './userservice';

@Component({
  selector: 'App',
  template: `<h3>App component</h3> …