angular - ngModel 不显示该值

Question

在 Html 中，它不显示已分配 selectedValueModel 的 ngModel 。
也尝试过[ngValue]，它给我的ngModelChange函数提供了undefined。

提前致谢。

foods: Food[] = [
    {value: 'steak-0', viewValue: 'Steak'},
    {value: 'pizza-1', viewValue: 'Pizza'},
    {value: 'tacos-2', viewValue: 'Tacos'}
  ];
selectedValueModel = {value: 'steak-0', viewValue: 'Steak'};
@Output() selectedValueChange = new EventEmitter()

changing(newValue: any) {
    this.selectedValueModel = newValue
    this.selectedValueChange.emit(newValue)
  }

我的 HTML:

<mat-form-field>
    <mat-select placeholder="Favorite food" 
   [(ngModel)]="selectedValueModel.value" 
   (ngModelChange)="changing($event)" name="food">
      <mat-option *ngFor="let food of foods" [value]="food.value">
        {{food.viewValue}}
      </mat-option>
    </mat-select>
  </mat-form-field>

Answer 1

更改:

<mat-form-field>
<mat-select placeholder="Favorite food" 
[(ngModel)]="selectedValueModel.value"
(ngModelChange)="changing($event)" name="food">
  <mat-option *ngFor="let food of foods" [value]="food.value">
    {{food.viewValue}}
  </mat-option>
</mat-select>

至:

<mat-form-field>
<mat-select placeholder="Favorite food" 
[(ngModel)]="selectedValueModel"
(ngModelChange)="changing($event)" name="food">
  <mat-option *ngFor="let food of foods" [value]="food.value">
    {{food.viewValue}}
  </mat-option>
</mat-select>