如何將表單輸入綁定到對象？

Question

我有以下形式：

<form role="form" [ngFormModel]="userEditForm" (ngSubmit)="editUser(user)"> 
<div> 
    <label for="username">Username</label> 
    <input type="text" #username id="username" placeholder="Username" [ngFormControl]="userEditForm.controls['username']"> 
</div> 
<div> 
    <label for="firstName">First Name</label> 
    <input type="text" #firstName id="firstName" placeholder="First Name" [ngFormControl]="userEditForm.controls['firstName']"> 
</div> 
<div> 
    <label for="lastName">Last Name</label> 
    <input type="text" #lastName id="lastName" placeholder="Last Name" [ngFormControl]="userEditForm.controls['lastName']"> 
</div> 
<div> 
    <label for="email">Email</label> 
    <input type="text" #email id="email" placeholder="Email" [ngFormControl]="userEditForm.controls['email']"> 
</div> 
<button type="submit">Submit</button> 

而在我的部分我已經定義：

 constructor(private _routeParams:RouteParams, private _formBuilder:FormBuilder, private _UserInject:UserInject){ 
    this.userEditForm = _formBuilder.group({ 
     'firstName': [this.user.firstName], 
     'lastName': [this.user.lastName], 
     'username': [this.user.username], 
     'email': [this.user.email], 
    }) 
} 

ngOnInit(){ 
    let id = this._routeParams.get('userId'); 
    this.user = this._UserInject.getUser(id); 
} 

}

然而，這產生了一個錯誤，因爲this.user尚未在構造函數中定義。有任何想法嗎？

UPDATE

它的工作原理，當我在ngOnInit使用formBuilder - 但是，我不知道如果多數民衆贊成一個適當的方式做到這一點。

Answer 1

只是移動

this.userEditForm = _formBuilder.group({ 
    'firstName': [this.user.firstName], 
    'lastName': [this.user.lastName], 
    'username': [this.user.username], 
    'email': [this.user.email], 
}) 

代碼後，你指定this.user（進入ngOnInit()）