你好，ngModelChange在这里没有解决的问题是什么？
<input hidden [(ngModel)]="Monday" type="checkbox" name="monday" id="monday" value="monday" (ngModelChange)="changed()">
<label class="btn btn-event-repeat" (click)="Monday = !Monday">
<span class="daylongname">Monday</span>
<span class="dayshortname">Mon</span>
</label>