javascript - 如何在 Angular 6 的单选按钮中执行验证？

Question

实际上我有两种输入类型:一种是普通文本，另一种是 radio 类型。我想在输入提交按钮之前验证这两个字段。

对于这个正常的输入字段，我进行了验证，但我不知道如何为单选按钮做。如果用户没有选择任何单选按钮，我想验证。

<form  name="form" #f="ngForm" (ngSubmit)="f.form.valid && onSubmit()" novalidate class="feedback-form">
         <div class="col-md-12">

            <div class="form-group col-md-4">
               <label for="selectionDate">Selection Date</label>
               <input type="text" 
               id="selectionDate"
               class="form-control"
                name="selectionDate"
                placeholder="Please enter the date" 
               [(ngModel)]="selection.selectionDate"
                #selectionDate="ngModel"
                [ngClass]="{ 'is-invalid': f.submitted && selectionDate.invalid }"
                 required
                  />

             <div *ngIf="f.submitted && selectionDate.invalid" class="invalid-input">
            <!-- individual validation errors -->
            <div *ngIf="selectionDate.errors?.required">DateField is required</div>
          </div>

            </div>
            <div class="form-group col-md-4">
               <label for="selectedBy">Selected By</label>
               <br>
               <label class="radio-inline">
               <input type="radio" name="selectedBy" 
               [(ngModel)]="selection.selectedBy" value="Department">Department
               </label>
               <label class="radio-inline">
               <input type="radio" name="selectedBy"  
               [(ngModel)]="selection.selectedBy" value="Office">Office
               </label>
            </div>
         </div>
</form>

Answer 1

和之前验证输入元素的方式是一样的

        <div class="form-group col-md-4">
           <label for="selectedBy">Selected By</label>
           <br>
           <label class="radio-inline">
           <input type="radio" name="selectedBy" 
           [(ngModel)]="selection.selectedBy" value="Department" required
                           #selectedBy="ngModel">Department
           </label>
           <label class="radio-inline">
           <input type="radio" name="selectedBy"  
           [(ngModel)]="selection.selectedBy" value="Office" required>Office
           </label>
        <div *ngIf="selectedBy.errors?.required">selectedBy is required</div>
      </div>

demo