不检查angular2中的复选框

Question

我有要显示的对象列表

public weeks = [
{ value: 'All', display: 'All',isChecked: false },
{ value: 'Mon', display: 'Mon',isChecked: false },
{ value: 'Tue', display: 'Tue',isChecked: false },
{ value: 'Wed', display: 'Wed',isChecked: false },
{ value: 'Thu', display: 'Thu',isChecked: false },
{ value: 'Fri', display: 'Fri',isChecked: false }
];

app.component.html

      <span *ngFor="let week of weeks">
        <label>
          <input type="checkbox" name="weeks" [(ngModel)]="week.isChecked" class="week" >
          {{week.display}}
        </label>
      </span>

问题是它现在绑定选中的复选框。

app.component.ts

this.weeks.forEach((month) => {
    var i = this.selected_weeks.indexOf(month.week);
    if(i != -1) {
      week.isChecked = true;
      console.log(week.isChecked);
    }
  });

在组件中，它标记该对象为true但在视图中未选中