angular2 + ngModel不能绑定表达式吗？

Question

<input type="text" name="username" [(ngModel)]="{{_current + 1}}">

as the code, I want to banding an expression to ngModel, but report error, why? and how can I do it?

Answer 1

You can use ngModelChange :

@Component(
 selector: 'my-component',
 templateUrl: './my-component.component.html',
)
export class MyComponent{
 _current: number;

 onChange(){
   this._current= this._current+ 1;
 }
}

my-component.component.html

<input type="text" name="username" [(ngModel)]="_current" (ngModelChange)="onChange()">

Answer 2

您无法使用插值方法与模型绑定，您应该这样做（没有{{}} ）：

<input type="text" name="username" [(ngModel)]="_current">