如何检测Angular 2中的属性是否发生了变化？

Question

我有简单的类，它看起来是这样的：

export class MessagesPage { 

    @ViewChild(Content) content: Content; 

    public message = ''; 
    public messages = []; 

    public state = 'general'; 
} 

是否有可能里面如果state属性更改类检测？

Answer 1

使他们获得和setter。没有其他方式可以得到有关更改的通知：

export class MessagesPage { 

    @ViewChild(Content) content: Content; 

    public message = ''; 
    public messages = []; 

    private _state = 'general'; 
    public get state() { return this._state; } 
    public set state(value:string) { 
     this._state = value; 
     console.log('state changed', this._state); 
    } 
}