Angular2 RC5教程：无法绑定到'ngModel'，因为它不是'input'的已知属性

Question

Following the Angular 2 "Hero tour" tutorial , I encounter the following error:

Unhandled Promise rejection: Template parse errors:  
Can't bind to 'ngModel' since it isn't a known property of 'input'. ("
    <div>
      <label>name: </label>
      <input [ERROR ->][(ngModel)]="hero.name" placeholder="name">
    </div>
    "): AppComponent@6:13 ; Zone: <root> ; Task: Promise.then ; Value: 

My package.json content is:

{
  "name": "angular2-quickstart",
  "version": "1.0.0",
  "scripts": {
    "start": "tsc && concurrently \"npm run tsc:w\" \"npm run lite\" ",
    "lite": "lite-server",
    "postinstall": "typings install",
    "tsc": "tsc",
    "tsc:w": "tsc -w",
    "typings": "typings"
  },
  "license": "ISC",
  "dependencies": {
    "@angular/common": "2.0.0-rc.5",
    "@angular/compiler": "2.0.0-rc.5",
    "@angular/core": "2.0.0-rc.5",
    "@angular/forms": "0.3.0",
    "@angular/http": "2.0.0-rc.5",
    "@angular/platform-browser": "2.0.0-rc.5",
    "@angular/platform-browser-dynamic": "2.0.0-rc.5",
    "@angular/router": "3.0.0-rc.1",
    "@angular/router-deprecated": "2.0.0-rc.2",
    "@angular/upgrade": "2.0.0-rc.5",
    "systemjs": "0.19.27",
    "core-js": "^2.4.0",
    "reflect-metadata": "^0.1.3",
    "rxjs": "5.0.0-beta.6",
    "zone.js": "^0.6.12",
    "angular2": "^2.0.0-beta.17",
    "angular2-in-memory-web-api": "0.0.15",
    "bootstrap": "^3.3.6"
  },
  "devDependencies": {
    "concurrently": "^2.0.0",
    "lite-server": "^2.2.0",
    "typescript": "^1.8.10",
    "typings":"^1.0.4"
  }
}

app.module.ts content:

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 { }

And app.component content :

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: 'Windstorm'
    };
}

I spent time to read and apply solutions proposed in similar question on stackoverflow with no success.

What could be wrong?

Solution :

use

//main entry point
import {platformBrowserDynamic} from '@angular/platform-browser-dynamic';
import {AppModule} from './app';

platformBrowserDynamic().bootstrapModule(AppModule)

instead of :

import { bootstrap }    from '@angular/platform-browser-dynamic';
import { AppComponent } from './app.component';
bootstrap(AppComponent);

Answer 1

Your app.module.ts should look like this:

 import { NgModule } from '@angular/core'; import { BrowserModule } from '@angular/platform-browser'; import { FormsModule, provideForms, disableDeprecatedForms } from '@angular/forms'; import { AppComponent } from './app.component'; @NgModule({ imports: [ BrowserModule, FormsModule ], declarations: [ AppComponent ], bootstrap: [ AppComponent ], providers: [ disableDeprecatedForms(), provideForms()], }) export class AppModule { } 

UPDATE: this is now obsolete with RC6 and beyond

Answer 2

In RC6 it looks like this:

...
import { FormsModule } from '@angular/forms';

@NgModule({
    imports: [ ..., FormsModule ],
    declarations: [ AppComponent ],
    bootstrap: [ AppComponent ]
})

export class AppModule { }

Ie provideForms , disableDeprecatedForms are removed as deprecated. Check https://github.com/angular/angular/blob/master/CHANGELOG.md for details.

Answer 3

Thanks for it, unless that part...nothing going on! import { FormsModule, provideForms, disableDeprecatedForms } from '@angular/forms';

Answer 4

A similar error occurs if you don't update the app.modules.ts file as required. That is adding the following import

import { FormsModule }   from '@angular/forms';

and the FormsModule as follows:

 imports: [ BrowserModule, FormsModule ],  

Answer 5

The app works fine. But I had this error in tests. You should import FormsModule in app.component.spec.ts like in app.module.ts to fix this.