Angular2中监听数据更新的方法

import { Component, DoCheck } from "@angular/core";export class LangListUserComponent implements DoCheck {

constructor(private differs: KeyValueDiffers) {}

ngOnInit() { this.objDiffer = {}; this.list.forEach((elt) => {  this.objDiffer[elt] = this.differs.find(elt).create(null); });}

ngDoCheck() { this.list.forEach(elt => {  var objDiffer = this.objDiffer[elt];  var objChanges = objDiffer.diff(elt);  if (objChanges) {   objChanges.forEachChangedItem((elt) => {    if (elt.key === 'prop1') {     this.doSomethingIfProp1Change();    }   });  } });}

<input type="text" pInputText size="50" [formControl]="term" placeholder="输入搜索条件">

colo = new FormControl();

this.colo.valueChanges.distinctUntilChanged().subscribe((ast) => {//do something})