Angular StaticInjectorError

Question

嗨，我正在使用angular进行新工作，所以我按照youtube教程建立聊天。 这个项目在业主github-＆gt; https://github.com/wesdoyle/base-chat

我尝试将AngularFireDatabase添加到仍无法正常工作的提供商。 我不知道为什么当我尝试登录时出现此错误。

这是我的 app.module.ts 文件：

import { BrowserModule } from '@angular/platform-browser';
import { NgModule } from '@angular/core';
import { FormsModule } from '@angular/forms';
import { RouterModule } from '@angular/router';
import { AppComponent } from './app.component';
import { AngularFireModule } from 'angularfire2';
import { AngularFireDatabaseModule } from 'angularfire2/database';
import { AngularFireAuthModule } from 'angularfire2/auth';



import { ChatFormComponent } from './chat-form/chat-form.component';
import { ChatroomComponent } from './chatroom/chatroom.component';
import { FeedComponent } from './feed/feed.component';
import { MessageComponent } from './message/message.component';
import { LoginFormComponent } from './login-form/login-form.component';
import { SignupFormComponent } from './signup-form/signup-form.component';
import { NavbarComponent } from './navbar/navbar.component';
import { UserListComponent } from './user-list/user-list.component';
import { UserItemComponent } from './user-item/user-item.component';

import { ChatService } from './services/chat.service';
import { AuthService } from './services/auth.service';

import { appRoutes } from '../routes';
import { environment } from '../environments/environment';


@NgModule({
  declarations: [
    AppComponent,
    ChatFormComponent,
    ChatroomComponent,
    FeedComponent,
    MessageComponent,
    LoginFormComponent,
    SignupFormComponent,
    NavbarComponent,
    UserListComponent,
    UserItemComponent
  ],
  imports: [
    BrowserModule,
    RouterModule.forRoot(appRoutes),
    FormsModule,
    AngularFireModule,
    AngularFireDatabaseModule,
    AngularFireAuthModule,
    AngularFireModule.initializeApp(environment.firebase)
  ],
  providers: [AuthService,ChatService],
  bootstrap: [AppComponent]
})
export class AppModule { }

那就是 login-form.component.ts ，我抛出错误。

import { Component, OnInit } from '@angular/core';
import { AuthService } from '../services/auth.service';
import { AngularFireDatabase} from 'angularfire2/database';
import { Router } from '@angular/router';


@Component({
  selector: 'app-login-form',
  templateUrl: './login-form.component.html',
  styleUrls: ['./login-form.component.css']
})
export class LoginFormComponent {
  email: string;
  password: string;
  errorMsg: string;

  constructor(private authService: AuthService, private router: Router) { }

  login() {
    console.log('login() called from login-form component');
    this.authService.login(this.email, this.password)
    .catch(error => this.errorMsg = error.message);
  }
}

这是 chat.service.ts ：

import { Injectable } from '@angular/core';
import { AngularFireModule } from 'angularfire2';
import { AngularFireDatabase, FirebaseListObservable, FirebaseObjectObservable } from 'angularfire2/database-deprecated';
import { AngularFireAuth } from 'angularfire2/auth';
import { Observable,of } from 'rxjs';
import { AuthService } from '../services/auth.service';
import * as firebase from 'firebase/app';

import { ChatMessage } from '../models/chat-message.model';

@Injectable()
export class ChatService {
  user: firebase.User;
  chatMessages: FirebaseListObservable<ChatMessage[]>;
  chatMessage: ChatMessage;
  userName: Observable<string>;

  constructor(
    private db: AngularFireDatabase,
    private afAuth: AngularFireAuth
    ) {
        this.afAuth.authState.subscribe(auth => {
          if (auth !== undefined && auth !== null) {
            this.user = auth;
          }

          this.getUser().subscribe(a => {
            this.userName = a.displayName;
          });
        });
    }

  getUser() {
    const userId = this.user.uid;
    const path = `/users/${userId}`;
    return this.db.object(path);
  }

  getUsers() {
    const path = '/users';
    return this.db.list(path);
  }

  sendMessage(msg: string) {
    const timestamp = this.getTimeStamp();
    const email = this.user.email;
    this.chatMessages = this.getMessages();
    this.chatMessages.push({
      message: msg,
      timeSent: timestamp,
      userName: this.userName,
      email: email });
  }

  getMessages(): FirebaseListObservable<ChatMessage[]> {
    // query to create our message feed binding
    return this.db.list('messages', {
      query: {
        limitToLast: 25,
        orderByKey: true
      }
    });
  }

  getTimeStamp() {
    const now = new Date();
    const date = now.getUTCFullYear() + '/' +
                 (now.getUTCMonth() + 1) + '/' +
                 now.getUTCDate();
    const time = now.getUTCHours() + ':' +
                 now.getUTCMinutes() + ':' +
                 now.getUTCSeconds();

    return (date + ' ' + time);
  }
}

Answer 1

在您的chart.service.ts中，您的导入错误，

更改

这

import { AngularFireDatabase, FirebaseListObservable, FirebaseObjectObservable } from 'angularfire2/database-deprecated';

要

import { AngularFireDatabase,FirebaseListObservable,FirebaseObjectObservable } from 'angularfire2/database';

Answer 2

您忘记在组件中提供服务

@Component({
  selector: 'app-login-form',
  templateUrl: './login-form.component.html',
  styleUrls: ['./login-form.component.css'],
  providers: [AuthService]
})

希望这会有所帮助。