绑定组件对象以形成元素

Question

我已经在angular2中创建了模型驱动的表单，我在html模板中创建了具有相同名称指令的对象，但不知怎的，如下图所示会出现错误：

postmessage.component.ts：

import { Component } from '@angular/core';
import {FormControl,FormGroup,FormBuilder,Validators} from '@angular/forms';

@Component({
    moduleId:module.id,
    selector: 'post-message',
    templateUrl: '../../templates/postmessage.component.html'
})
export class PostComponent {
    form = new FormGroup({
        username:new FormControl('',Validators.required),
        email:new FormControl('',Validators.required)
    })
    signup(){
        console.log(this.form.value);
    }
 }

postmessage.component.html：

<form class="from-horizontal" [formGroup]="form" (ngSubmit)="signup()">
    <div class="form-group row">
        <label for="username" class="control-label col-md-2">Name:</label>
        <div class="col-md-6">
            <input type="text" id="username"  class="form-control" formControlName="username">
            <div class="alert alert-danger"
            *ngIf="!form.controls['username'].valid"
            >
                User name is required.
            </div>
        </div>
    </div>
    <div class="form-group row">
        <label for="email" class="control-label col-md-2">Email:</label>
        <div class="col-md-6">
            <input type="email" id="email" class="form-control" formControlName="email">
        </div>
        <div class="alert alert-danger"
        *ngIf="!from.controls['email'].valid"
        ></div>
    </div>
    <div class="form-group row">
        <label for="" class="control-label col-md-2"></label>
        <div class="col-md-6">
            <input type="submit" class="btn btn-primary">
        </div>
        </div>
</form>

如何解决？

Answer 1

form = new FormControl({

应该是

form = new FormGroup({