angular2 模型資料更新了，需要監聽資料改變，

一、實現介面Docheck，檢測頁面上所有元素資料更

1. import { Component, DoCheck } from "@angular/core";

2. export class LangListUserComponent implements DoCheck {

1. constructor(private differs: KeyValueDiffers) {

2. }

1. ngOnInit() {

2. this.objDiffer = {};

3. this.list.forEach((elt) => {

4. this.objDiffer[elt] = this.differs.find(elt).create(null);

5. });

6. }

1. ngDoCheck() {

2. this.list.forEach(elt => {

3. var objDiffer = this.objDiffer[elt];

4. var objChanges = objDiffer.diff(elt);

5. if (objChanges) {

6. objChanges.forEachChangedItem((elt) => {

7. if (elt.key === 'prop1') {

8. this.doSomethingIfProp1Change();

9. }

10. });

11. }

12. });

13. }

二、針對頁面上某個元素的資料更新做處理

1、定義模板驅動表單名 

<input type="text" pInputText size="50" [formControl]="term" placeholder="輸入搜尋條件">

2、ts 檔案中新建一個表單元素物件。

colo = new FormControl(); 3、ngonInit中訂閱資料更新

this.colo.valueChanges.distinctUntilChanged().subscribe((ast) => {

//do something

})