Angular 中带有子组件的反应式形式

Question

如您所见，我有一个带有子组件的父表单组件。{{myFormFather.value}} 显示我的nickName价值和name价值，但不显示age价值。{{myFormFather.status}} 它不识别组件子级。就像我的孩子是一个幻影，为什么？

我的-form-father.html

<form [formGroup]="myFormFather" (ngSubmit)="onSubmit()">
    <input formControlName="nickName">
    <input formControlName="name">
    <my-form-child
            [age]="myFormFather">
    </my-form-child>
    <button type="submit"
            [disabled]="myFormFather.invalid">Save
    </button>
</form>

my-form-father.ts

myFormFather = new FormGroup({
    nickName: new FormControl(),
    name: new FormControl()
});

constructor(private fb:FormBuilder) {}

ngOnInit() {this.createForm()}

createForm() {
    this.myFormFather = this.fb.group({
        nickName: ['', [Validators.required],
        name: ['', [Validators.required]
    });
}

my-form-child.html

<div [formGroup]="ageForm">
    <input formControlName="age">
</div>

my-form-child.ts

@Input() ageForm = new FormGroup({
    age: new FormControl()
});

constructor(private fb:FormBuilder) {}

ngOnInit() {this.createForm()}

createForm() {
    this.ageForm = this.fb.group({
        age: ['', [Validators.required]]
    });
}

Answer 1

您好，您一直在寻找的解决方案

演示堆栈闪电战

问题是：您覆盖了从父级传递的表单组

@Input() ageForm = new FormGroup({
  age: new FormControl()
});

constructor(private fb: FormBuilder) {}

ngOnInit() {
  this.createForm()
}

createForm() {
  // This is overwriting the FormGroup passed from parent!
  this.ageForm = this.fb.group({
    age: ['', [Validators.required]]
  });

  // Instead you had to use
  // this.ageForm.addControl("age", new FormControl('', Validators.required));
}