Angular 单选按钮问题

Angular Radio button Issue

每当我点击单选按钮 "second" 我必须点击它两次才能选中它。

ngModel不接受! (否定)?

<div class="form-check">
  <label class="custom-radio black">first
    <input type="radio" name="name" required [value]=false [(ngModel)]="!selectedValue" class="black" checked="true">
    <span class="checkdot"></span>
  </label>
</div>
<div class="form-check">
  <label class="custom-radio black">second
    <input type="radio" name="name" [(ngModel)]="selectedValue" required [value]=true checked="true" class="black">
    <span class="checkdot"></span>
  </label>
</div>

两者应该 [(ngModel)]="selectedValue" 相同,

作为它的单选按钮,所以它一次只能有一个值,也不需要checked="true",一旦[(ngModel)][value]相同,它就会被标记值

WORKING DEMO