相关疑难解决方法(0)

我正在使用表单控件，这是我的html组件的代码

<mat-form-field>
  <mat-select placeholder="Toppings" [formControl]="toppings" multiple>
    <mat-option *ngFor="let topping of toppingList" [value]="topping">{{topping.value}}</mat-option>
  </mat-select>
</mat-form-field>

我的ts文件是

export class SelectMultipleExample {
   toppings = new FormControl();
  toppingList: any[] = [
      { id:1,value:"test 1"},
      { id:2,value:"test 2"},
      { id:3,value:"test 4"},
      { id:4,value:"test 5"},
      { id:5,value:"test 6"},
      { id:6,value:"test 7"}
    ];

  

  constructor(){
    this.bindData();
  }

  bindData(){
    const anotherList:any[]=[
      { id:1,value:"test 1"},
      { id:2,value:"test 2"}
      ]

      this.toppings.setValue(anotherList)
  }
}

我想为mat select设置默认值，如何实现这一点的任何帮助都会很棒。我想设置多个默认值。

I have a select dropdown and I iterate the options from a list. I am trying to set as selected a separate option (as a default), in case of user is not selecting a value.

Here is how I am trying to implement that:

<select [(ngModel)]="book.pageLayout">
    <option [value]="0" [attr.selected]="book.defaultLayoutId === null">No Default Layout</option>
    <option *ngFor="let l of availableLayouts"
            [value]="l.id"
            [attr.selected]="book.pageLayout == l.id">
      {{l?.name}}
    </option>
  </select>

I also tried:

<option [value]="0" selected="selected">No Default Layout</option>

and even:

<option [value]="0" selected="1==1">No Default Layout</option> …