Angular2 FormGroup - 如何确定哪个控件触发了值更改

Question

我想在表单发生变化时取消选中复选框。该复选框是该表单的一部分，因此我只想在值更改来自该复选框以外的任何其他控件时取消选中它。

我正在像这样订阅 FormGroup 的值更改

import { FormBuilder, FormGroup } from '@angular/forms';
export class App {
    form : FormGroup;
    constructor(private formBuilder: FormBuilder) {
        this.form = formBuilder.group({
            firstName: 'Thomas',
            lastName: 'Mann',
            ... many more fields ...
            checkbox: true
        })

        this.form.valueChanges.subscribe(data => {
            //if valueChange was not triggered by change in the checkbox
            this.form.get('checkbox').setValue(false);
        })
    }
}

我可以单独订阅每个其他控件中的 valueChanges，但我想避免这样做

Answer 1

使用嵌套表单组...将所有其他 formControl 分组到您要更新复选框值的单个 formGroup 中...

例如:

import { FormBuilder, FormGroup } from '@angular/forms';  

export class App {
    form : FormGroup;

    constructor(private formBuilder: FormBuilder) {
        this.form = formBuilder.group({
            'otherFormField': this.fb.group({
                firstName: 'Thomas',
                lastName: 'Mann',
                ... many more fields ...
            }),       
            checkbox: true
        })

        this.form.otherFormField.valueChanges.subscribe(data => {
            //if valueChange was not triggered by change in the checkbox
            this.form.get('checkbox').setValue(false);
        })
    }