angular6：如何在隐藏和显示表单控件之间切换

Question

我无法使用嵌入 Angular6 反应形式的 select 在隐藏和显示控件之间切换。我希望当用户 select 选项 3 在 garde form controll 中显示名称 form controll。

this.form = this.fb.group({
  id: [null, Validators.compose([Validators.required])],
  name: [null, Validators.compose([Validators.required])],
  grade: [null, Validators.compose([Validators.required])],

});

.html

<mat-form-field class="mb-1">
<input  matInput  " [formControl]="form.controls['id']">
</mat-form-field>


<mat-form-field class="mb-1">
<mat-select  [formControl]="form.controls['grade']">

<mat-option value="option1">option1</mat-option>
<mat-option value="option2">option2</mat-option>
<mat-option value="option3">option3</mat-option>
</mat-select>
</mat-form-field>

<mat-form-field class="mb-1">
<input  matInput  " [formControl]="form.controls['name']">
</mat-form-field>

Answer 1

最快的解决方案是，虽然不是很优雅：

<mat-form-field class="mb-1" *ngIf="form.controls['grade'].value == 'option3'">
  <input  matInput [formControl]="form.controls['name']">
</mat-form-field>

angular6：如何在隐藏和显示表单控件之间切换

angular6: How to toggle between hiding and showing a form control

forms

angular5

angular6

angular-reactive-forms

form-control