angular2 動態添加input輸入框

export class TComponent {

    username: any;
    id: number = 1;
    login:any = [{"username": "username" + this.id,"password": "pwd" + this.id}];

    addInput() {
        var number = this.login.length + 1;
        this.login.push({"username": "username" + number, "password": "pwd" + number});
    }

    removeInput(item) {
        console.log(item);
        let i = this.login.indexOf(item);
        console.log(i);
        this.login.splice(i, 1);
    }

}

<h5>動態添加表單</h5>
<div class="form">
    <div class="form-group form-group-sm" *ngFor="let i of login">
        <label class="col-form-label">用戶名</label>
        <input class="form-control" [(ngModel)]="i.username" value="{{i.username}}">
        <label class="col-form-label">密碼</label>
        <input class="form-control" [(ngModel)]="i.password" value="{{i.password}}">
        <button class="btn btn-link" (click)="removeInput(i)">Remove</button>
    </div>
    <button class="btn btn-link" (click)="addInput()">Add</button>
    {{ login | json }}
</div>