Angular 4选择ngModel更改时不更新

Question

我试图使新值被选中后，调用eventChange（）函数并将选中的值恢复为默认值。但会发生什么：ngModel值更新，但所选值保持不变。我应该如何使selected值和ngModel值相同？

HTML文件

<select [(ngModel)]="selectedValue"
       (change)="eventChange()"

>
      <option [disabled]="true"
              [ngValue]="-1">
        Choose an option
      </option>
      <option *ngFor="let item of myList index as i"
              [ngValue]="i"
      >
        {{item.name}}
      </option>
</select>

selectedValue = -1; //works //Option in select is changed
eventChange(){
    this.selectedValue= -1; //don't work 
    //Function is called, 
    //Value changes
    //But selected Option in Select doesn't change
}

更新：以防万一的澄清：正在调用函数，但我想通过JavaScript更改所选选项。我尝试通过更改ngModel值来实现这一点，但即使ngModel值为cahnged时，所选选项也不会更改。

Answer 1

使用ngModelChange，您不需要[ngValue]

<select [(ngModel)]="selectedValue"
       (ngModelChange)="eventChange()"