1. 确保你的服务文件中，@Injectable装饰器下使用了@Injectable()，而不是@Inject()

import { Injectable } from '@angular/core';

@Injectable({
  providedIn: 'root'
})
export class DataService { }

2. 将你的服务文件添加到AppModule中的providers数组中

import { NgModule } from '@angular/core';
import { BrowserModule } from '@angular/platform-browser';
import { AppComponent } from './app.component';
import { DataService } from './data.service';

@NgModule({
  declarations: [
    AppComponent
  ],
  imports: [
    BrowserModule
  ],
  providers: [DataService], // 添加到providers
  bootstrap: [AppComponent]
})
export class AppModule { }

3. 在组件中注入服务

import { Component } from '@angular/core';
import { DataService } from './data.service';

@Component({
  selector: 'app-root',
  template: `
    
{{message}}
  `
})
export class AppComponent {
  message: string;

  constructor(private dataService: DataService) {
    this.message = this.dataService.getMessage();
  }
}

4. 在视图中绑定数据

import { Component } from '@angular/core';
import { DataService } from './data.service';

@Component({
  selector: 'app-root',
  template: `
    
{{message}}
  `
})
export class AppComponent {
  message: string;

  constructor(private dataService: DataService) {}

  ngOnInit() {
    this.dataService.getMessage().subscribe(message => {
      this.message = message;
    });
  }
}