title: Error: Uncaught (in promise): Error: No provider for - ionic 3
body: <p>Im Create new Ionic page name for <code>listing</code>  and i m added some file its name <code>listing.service.ts</code> after  I cant  open this <code>listing</code> page i had some error</p>
  
  <pre><code>Error: Uncaught (in promise): Error: No provider for ListingService!
  Error: No provider for ListingService!
  </code></pre>
  
  <p>Im try to fix it for more than one hour but cant  found any solutions , how to fix it ?
  Thanks 
  <strong>This is my code</strong></p>
  
  <p><strong>listing.module.ts</strong></p>
  
  <pre><code>import { NgModule } from '@angular/core';
  import { IonicPageModule } from 'ionic-angular';
  import { ListingPage } from './listing';
  import  {ListingService} from "./listing.service";
  
  @NgModule({
    declarations: [
      ListingPage,
    ],
    imports: [
      IonicPageModule.forChild(ListingPage),
    ],
    providers: [
      ListingService
    ]
  })
  export class ListingPageModule {}
  </code></pre>
  
  <p><strong>listing.service.ts</strong></p>
  
  <pre><code>import {Injectable} from '@angular/core';
   @Injectable()
      export class ListingService {
        private eventMap:any;
        constructor() {
          this.initEventMap();
        }
  </code></pre>
  
  <p><strong>app.module.ts</strong></p>
  
  <pre><code>import {ListingService} from "../pages/listing/listing.service";
  
  const providers = [ ListingService ];
  
  @NgModule({
    declarations: [
      MyApp,
      HomePage
  
  
  
  
    ],
    imports: [
      BrowserModule,
      IonicModule.forRoot(MyApp),
      CalendarModule, // Ionic Calendar
  
    ],
    bootstrap: [IonicApp],
    entryComponents: [
      MyApp,
      HomePage
  
    ],
    providers: [
      StatusBar,
      SplashScreen,
      {provide: ErrorHandler, useClass: IonicErrorHandler}
    ]
  })
  export class AppModule {}
  </code></pre>