无法注入组件？[副本]

Question

import { BrowserModule } from '@angular/platform-browser';
import { NgModule } from '@angular/core';
import { AppComponent } from './app.component';
import { AngularFireModule } from 'angularfire2';
import { AngularFireDatabaseModule, AngularFireDatabase } from 'angularfire2/database';
import { environment } from '../environments/environment';
import { MyService } from './my.service';

@NgModule({
  declarations: [
    AppComponent
  ],
  imports: [
    BrowserModule,
    AngularFireDatabaseModule,
    AngularFireModule.initializeApp(environment.firebase)
  ], 
  //providers:[],  
  providers: [MyService],
  bootstrap: [AppComponent]
})
export class AppModule { }

import { Component, Inject, Injectable, HostListener } from '@angular/core';
import { AngularFireDatabaseModule, AngularFireDatabase } from 'angularfire2/database';
import { Observable } from 'rxjs/Observable';
import { VendingMachineService } from './vending-machine.service';

@Component({
  selector: 'app-root',
  templateUrl: './app.component.html',
  styleUrls: ['./app.component.css']
})
export class AppComponent 
{

/*
    constructor()
    {
    }
*/  

    constructor(ms)         
    {
        var x = vms;
    }
}

My.Service.ts：

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

@Injectable()
export class MyService {

    constructor() { }

    public test(){ } 
}

Answer 1

重写

app.component.ts:

import { Component } from '@angular/core';
import { Observable } from 'rxjs/Observable';
import { VendingMachineService } from './vending-machine.service';

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

export class AppComponent {

//please check vendingMachineService, this is not the name of the service you provided in code
    constructor(private vendingMachineService: VendingMachineService){}

/*
    constructor(ms)     what is ms????? remove
    {
        var x = vms;
    }
*/
}

为什么要在应用程序模块中导入已经导入的模块？如果你想这样做，我不这么认为，你需要声明另一个模块

您可能需要考虑将服务重命名为my-service.service.ts，这样看起来更好