如何在初始加载后调用角度窗体生成器值更改

this.profileFormStageOne.get('nationality').valueChanges.subscribe(val => {
      if (val && val === 'Other') {
        let alert = this.alertCtrl.create({
          title: 'Your Nationality',
          inputs: [
            {
              name: 'nationality',
              placeholder: 'Your Nationality e.g. Brazilian',
            },
          ],
          buttons: [
            {
              text: 'Update Nationality',
              handler: data => {
                this.manualNationality = data.nationality;
                console.log(this.manualNationality);
              },
            },
          ],
        });
        alert.present();
      }
    });

不过,我也使用ngOnChanges()来修补以下形式的值:

  /**
   * Get initial form values
   * Needs to run from ngOnChanges because User in an input & is not ready in constructor
   */
  ngOnChanges() {
    if (this.User) {
      const profile: Profile = this.User.profile;

      this.profileFormStageOne.patchValue({
        nationality: profile.nationality,

问题是,如果国籍字段已设置为“其他”,则在初始呈现(在修补程序值期间)上调用此函数。