Angular2 FormGroup-如何确定哪个控件触发了值更改

Question

每当表单发生更改时，我都想取消选中一个复选框。该复选框是该表单的一部分，因此我只想取消选中该复选框以外的其他任何控件来更改值时。

我正在订阅这样的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);
        })
    }
}

我可以分别在每个其他控件中订阅valueChanges，但要避免这样做

Answer 1

使用嵌套表单组...将所有其他formControl分组为单个formGroup，要在其上更新复选框值...

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);
        })
    }