Angular material 选中的属性在mat单选按钮中不起作用

我正在创建一个带有选中属性的单选按钮，但它没有显示选中的

<mat-radio-group name="radioOpt1" [(ngModel)]="selectedRadio" [ngModelOptions]="{standalone: true}" (change)="radioChange($event)">
<mat-radio-button value="own" checked name="own">Own</mat-radio-button>
<mat-radio-button value="competitor" name="own">competitor</mat-radio-button> </mat-radio-group>

拥有
竞争对手

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我希望默认选中第一个单选按钮

如果使用

ngModel

，则需要将单选按钮的值传递给

ngModel

<mat-radio-group name="radioOpt1" [(ngModel)]="selectedRadio" 
   [ngModelOptions]="{standalone: true}" (change)="radioChange($event)">
  <mat-radio-button value="own" name="own">Own</mat-radio-button>
  <mat-radio-button value="competitor" name="own">competitor</mat-radio-button> 
</mat-radio-group>

或动态填充

 <mat-radio-group name="radioOpt1" [(ngModel)]="selectedRadio"
    [ngModelOptions]="{standalone: true}" (change)="radioChange($event)">
   <mat-radio-button *ngFor="let but of list" [value]="but.id" name="own" >
      {{but.name}}
   </mat-radio-button>
 </mat-radio-group>

 <mat-radio-group name="radioOpt1" [(ngModel)]="selectedRadio"
    [ngModelOptions]="{standalone: true}" (change)="radioChange($event)">
   <mat-radio-button *ngFor="let but of list" [value]="but.id" name="own" >
      {{but.name}}
   </mat-radio-button>
 </mat-radio-group>

  list = [{ "name": "own", id: "own"},{ "name": "competitor", id: "competitor"}];

  selectedRadio =this.list[0].id;