Angular Form Control value更改不起作用

Question

我希望获得我的一个表单("系列")值,如果通过订阅更改但似乎有问题,因为我的控制台日志中没有任何内容.

import { Component , AfterViewInit } from '@angular/core';
import {FormGroup,FormBuilder} from '@angular/forms';
import {Observable} from 'rxjs/Rx';

@Component({
selector: 'app-root',
template: `<h1>Hello World!</h1>
            <form [formGroup]="frm1">
            <input type="text" formControlName="name" >
            <input type="text" formControlName="family">
            </form>
            `,

})

export class AppComponent implements AfterViewInit{ 

 frm1 : FormGroup;

constructor( fb:FormBuilder){
    this.frm1 = fb.group({
        name : [],
        family: []
    });     
}
ngAfterViewInit(){  
    var search = this.frm1.controls.family;
    search.valueChanges.subscribe( x => console.log(x));    
}
}

Answer 1

get在表单变量上使用方法frm1。并使用ngOnInit()代替ngAfterViewInit()

ngOnInit() {  
   this.frm1.get('family').valueChanges.subscribe( x => console.log(x));
}