无法绑定到'ngModel'，因为它不是'input'的已知属性，即使在app.module.ts中添加了FormsModule也是如此

Question

即使在app.module.ts文件中包含FormsModule，我也会收到此错误。

这是我的2个文件

app.module.ts

import { NgModule } from '@angular/core';
import { BrowserModule } from '@angular/platform-browser';
import { FormsModule }   from '@angular/forms';
import { AppComponent } from './app.component';

@NgModule({
  imports: [
    BrowserModule,
    FormsModule
  ],
  declarations: [
    AppComponent
  ],
  bootstrap: [ AppComponent ]
})
export class AppModule { }

app.component.ts

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

export class Hero {
  id: number;
  name: string;
}

@Component({
  selector: 'my-app',
  template: `<h1>{{title}}</h1>
  <h2>{{hero.name}} details!</h2>
  <div><label>id: </label>{{hero.id}}</div>
  <div>
    <label>name: </label>
    <input [(ngModel)]="hero.name" placeholder="name">
  </div>`,
})
export class AppComponent  {
  title = 'Tour of Heroes';
  hero: Hero = {
              id: 1,
              name: 'Magneto'
  };
 }

system.config.js

/**
 * System configuration for Angular samples
 * Adjust as necessary for your application needs.
 */
(function (global) {
  System.config({
    paths: {
      // paths serve as alias
      'npm:': 'node_modules/'
    },
    // map tells the System loader where to look for things
    map: {
      // our app is within the app folder
      app: 'app',

      // angular bundles
      '@angular/core': 'npm:@angular/core/bundles/core.umd.js',
      '@angular/common': 'npm:@angular/common/bundles/common.umd.js',
      '@angular/compiler': 'npm:@angular/compiler/bundles/compiler.umd.js',
      '@angular/platform-browser': 'npm:@angular/platform-browser/bundles/platform-browser.umd.js',
      '@angular/platform-browser-dynamic': 'npm:@angular/platform-browser-dynamic/bundles/platform-browser-dynamic.umd.js',
      '@angular/http': 'npm:@angular/http/bundles/http.umd.js',
      '@angular/router': 'npm:@angular/router/bundles/router.umd.js',
      '@angular/forms': 'npm:@angular/forms/bundles/forms.umd.js',

      // other libraries
      'rxjs':                      'npm:rxjs',
      'angular-in-memory-web-api': 'npm:angular-in-memory-web-api/bundles/in-memory-web-api.umd.js'
    },
    // packages tells the System loader how to load when no filename and/or no extension
    packages: {
      app: {
        defaultExtension: 'js'
      },
      rxjs: {
        defaultExtension: 'js'
      }
    }
  });
})(this);

我还添加了system.congig.js文件。 请帮助我，因为我是Angular2的新手