離子2無法讀取性能

Question

我有一個ionic2例如一個問題，我試着打電話給蒙山服務（birthday.service.ts）pouchdb功能誰與PouchDb從我的模塊添加數據（details.ts）

但我有我這個錯誤：

例外：錯誤./DetailsPage類DetailsPage - 聯模板：22：18造成的：無法讀取未定義

我的服務的特性「郵報」：birthday.service.ts

import{Injectable} from '@angular/core'; 
    import PouchDB from 'pouchdb' 

    @Injectable() 
    export class BirthdayService { 

    private _db; 
    private _birthdays; 



    initDB(){ 

     this._db = new PouchDB('http://localhost:5984/birthday4'); 

    } 

    add(birthday) { 
     return this._db.post(birthday); 
    } 

我的模塊：detail.ts

import { Component } from '@angular/core'; 
import { NavParams,ViewController} from 'ionic-angular'; 
import {BirthdayService} from '../../app/services/birthday.service'; 

@Component({ 

    templateUrl: 'details.html', 
    providers:[BirthdayService] 
}) 
export class DetailsPage { 

    public birthday; 
    public isNew = true; 
    public action = 'Add'; 
    public isoDate = ''; 

    constructor (private viewCtrl: ViewController, 
     private navParams: NavParams, 
     public birthdayService : BirthdayService 
    ) { 

    this.birthday = this.navParams.get('birthday'); 
    this.birthday = {Name:" "} 
    this.isNew=true; 

    } 




    save() { 
     this.birthday.Date = new Date(this.isoDate); 

     if (this.isNew) { 
      this.birthdayService.add(this.birthday) 
       .catch(console.error.bind(console)); 
     } else { 
      this.birthdayService.update(this.birthday) 
       .catch(console.error.bind(console)); 
     } 

     this.dismiss(); 
    } 



} 

Answer 1

你initDb()功能不叫，thefefore _db等於undefined

從@angular/core進口OnInit，並實現它