typescript Angular2：检测表单变化
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Angular2: Detect form changes
提问by Vingtoft
In Angular2 4.0 I have a FormGrouplooking like this:
在 Angular2 4.0 中，我FormGroup看起来像这样：
this.form = this._fb.group({
a: ['', [Validators.required]],
b: ['', [Validators.required]],
c: ['', [Validators.required]],
});
Is it possible to subscribe valueChangedon individual fields?
是否可以订阅valueChanged单个字段？
I dont want to detect changes on input c, so the below approach does not work:
我不想检测 input 的变化c，所以下面的方法不起作用：
this.form.valueChanges.debounceTime(400).subscribe(data => {
// Do something
});
回答by tottomotto
You can add separate subscriptions for FormControl aand b.
您可以为 FormControl a和b添加单独的订阅。
this.heroForm.controls["a"].valueChanges.subscribe(data => {
// Do something
});
this.heroForm.controls["b"].valueChanges.subscribe(data => {
// Do something
});
回答by Sujith S
//get form ref
@ViewChild('myForm') myForm;
//implement afterview init to your class and use
// or you can use same code with ngOnInit
ngAfterViewInit(){
this.myForm.valueChanges.debounceTime(500).subscribe(data => console.log('Form changes', data));
}You can use this code, it will give you changed field data also.
您可以使用此代码，它也会为您提供更改的字段数据。
