我如何 add/remove 验证器有条件地以反应形式出现？

Question

我有这样的反应形式

this.form = this.formBuilder.group({
  ...
  email: [],
  receiveNewsletter: [],
  ...
})

我希望所有字段都是可选的，除非用户选中 receiveNewsletter，电子邮件字段应该是必需的。我该怎么做？

Answer 1

您必须观察复选框的值，并根据 receiveNewsletter

的值添加或删除所需的验证器

this.form.controls.receiveNewsletter.valueChanges.subscribe(value => {
   if(value){
      this.form.controls.email.addValidators(Validator.required);
   } else {
      this.form.controls.email.removeValidators(Validator.required);
   }
   this.form.controls.email.updateValueAndValidity(); //remember to add this to update the form control state
})

我如何 add/remove 验证器有条件地以反应形式出现？

How can i add/remove validators conditionally in reactive forms?

javascript

angular