Angular 2 function inside callback value not updat

问题:

I have created function and inside function i'm calling one callback function after callback response I have update string variable but this string variable not updating my view.

import { Component } from 'angular2/core'; 

@Component({
    selector : "myview"
    templateUrl : 'app/view/myview.component.html'
})


export class ViewComponent {

        getAddress : string;
        public totlaBalance : string;

        getBalance():void{
             var self = this;
             getBalanceData(this.getAddress,function(error,res){
                 console.log(res);
                 self.totlaBalance = res;


            });
        }
}

In html file

<h1>Balance = {{totlaBalance}} </h1>

package.js

 "dependencies": {
        "angular2": "2.0.0-beta.15",
        "systemjs": "0.19.26",
        "es6-shim": "^0.35.0",
        "reflect-metadata": "0.1.2",
        "rxjs": "5.0.0-beta.2",
        "zone.js": "0.6.10",
        "bootstrap": "^3.3.6"
    },

In console value showing but in view value not updating.
I'm using 3rd party callback function its not allowing arrow function.

回答1:

You just need to use ArrowFunction (()=>) and ChangeDetectionRef as shown below,

import {Injectable, ChangeDetectorRef } from 'angular2/core';  //<<<===here

export class ViewComponent {
    getAddress : string;
    public totlaBalance : string;

     constructor(private ref: ChangeDetectorRef){}             //<<<===here

     getBalance():void{
             var self = this;
             getBalanceData(this.getAddress,(error,res)=>{    //<<<===here
                 console.log(res);
                 self.totlaBalance = res;
                 self.ref.detectChanges();                    //<<<===here
             });
     }
}

回答2:

The callback logic should be run within Angular Zone.

import { Component, NgZone } from '@angular/core'; 

@Component({
  selector: "myview"
  templateUrl: 'app/view/myview.component.html'
})

export class ViewComponent {
  getAddress: string;
  public totalBalance: string;

  constructor(private ngZone: NgZone) {}

  getBalance(): void {
    getBalanceData(this.getAddress, (error, result) => this.ngZone.run(() => {
      console.log(result);
      this.totalBalance = result;
    }));
  }
}