javascript - 错误 : Uncaught (in promise): TypeError: Cannot read property 'title' of undefined

Question

html文件

<ion-header>
  <ion-toolbar color="danger">
    <ion-buttons>
      <button ion-button navPop icon-only>
        <ion-icon ios="ios-arrow-back" md="md-arrow-back"></ion-icon>
      </button>
    </ion-buttons>
      <ion-title text-wrap>志愿者评选</ion-title>
  </ion-toolbar>
</ion-header>

<ion-content>
    <h1>{{volunteer.title}}</h1><br/>
</ion-content>

ts 文件

import { Component } from '@angular/core';
import { NavController, NavParams } from 'ionic-angular';


@Component({
  selector: 'page-volunteer-vote-detail',
  templateUrl: 'volunteer-vote-detail.html',
})

export class VolunteerVoteDetailPage {
  volunteer:any;

  constructor(public navCtrl: NavController, public navParams: NavParams) {
    this.volunteer = navParams.get('volunteer');
  }

}

在其他页面，我使用this.volunteer = navParams.get('volunteer');获取数据，但是这里无法获取数据并显示错误

错误:

ERROR Error: Uncaught (in promise): TypeError: Cannot read property 'title' of undefined TypeError: Cannot read property 'title' of undefined at Object.eval [as updateRenderer] (VM3975 VolunteerVoteDetailPage.ngfactory.js:64) at Object.debugUpdateRenderer [as updateRenderer] (VM3846 vendor.js:14729) at checkAndUpdateView (VM3846 vendor.js:13865) at callViewAction (VM3846 vendor.js:14210) at execComponentViewsAction (VM3846 vendor.js:14142) at checkAndUpdateView (VM3846 vendor.js:13866) at callWithDebugContext (VM3846 vendor.js:15092) at Object.debugCheckAndUpdateView [as checkAndUpdateView] (VM3846 vendor.js:14629) at ViewRef_.detectChanges (VM3846 vendor.js:11652) at Tab.NavControllerBase.viewAttachToDOM (VM3846 vendor.js:49817) at Object.eval [as updateRenderer] (VM3975 VolunteerVoteDetailPage.ngfactory.js:64) at Object.debugUpdateRenderer [as updateRenderer] (VM3846 vendor.js:14729) at checkAndUpdateView (VM3846 vendor.js:13865) at callViewAction (VM3846 vendor.js:14210) at execComponentViewsAction (VM3846 vendor.js:14142) at checkAndUpdateView (VM3846 vendor.js:13866) at callWithDebugContext (VM3846 vendor.js:15092) at Object.debugCheckAndUpdateView [as checkAndUpdateView] (VM3846 vendor.js:14629) at ViewRef.detectChanges (VM3846 vendor.js:11652) at Tab.NavControllerBase._viewAttachToDOM (VM3846 vendor.js:49817) at c (VM3844 polyfills.js:3) at Object.reject (VM3844 polyfills.js:3) at Tab.NavControllerBase._fireError (VM3846 vendor.js:49580) at Tab.NavControllerBase._failed (VM3846 vendor.js:49573) at VM3846 vendor.js:49620 at t.invoke (VM3844 polyfills.js:3) at Object.onInvoke (VM3846 vendor.js:4979) at t.invoke (VM3844 polyfills.js:3) at r.run (VM3844 polyfills.js:3) at VM3844 polyfills.js:3

编辑:

更新:

ts 文件

goToVolunteerVoteDetail(volunteerItem:any) {
    this.navCtrl.push(VolunteerVoteDetailPage,{
      volunteer:volunteerItem
    });
  }

html文件

(click)="goToVolunteerVoteDetail(volunteer)"

Answer 1

变量volunteer 似乎未定义。这是由于行中的错误:

this.volunteer = navParams.get('volunteer');

显然您没有发送名为 volunteer 的参数。因此 navParams 是空的。我的建议是去你推送(或路由)的任何页面并像这样使用 navcontroller:

this.navCtrl.push(VolunteerVoteDetailPage, {
      volunteer: "yourDATA"
    });