Ionic/Angular 2: Issue accessing object in the Page1 class - error caused by: Unable to retrieve the 'name' property as it is undefined

Question

Ionic/Angular 2: Issue accessing object in the Page1 class - error caused by: Unable to retrieve the 'name' property as it is undefined

Currently, I am working on developing an application using Ionic and below is the code snippet:

<ion-header>
  <ion-navbar>
    <button ion-button menuToggle>
      <ion-icon name="menu"></ion-icon>
    </button>
    <ion-title>Welcome</ion-title>
  </ion-navbar>
</ion-header>

<ion-content padding>
  <h3>Let's get started</h3>

  <p>
    Including some text here.
  </p>

  <ul>
    <li> {{ Schueler.name }} </li>
  </ul>

</ion-content>

The typescript definition for this code is as follows:

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

import { NavController , NavParams } from 'ionic-angular';
import { Student } from '../../app/student.components';

@Component({
  selector: 'page-page1',
  templateUrl: 'page1.html'
})
export class Page1 {

  constructor(public navCtrl: NavController) {
    var Schueler = new Student('Doldi');
    console.log(Schueler.name)
  }
}

While the instantiation of a new Schueler instance works perfectly fine and can be printed in the console without any issues.

However, I encountered an error message: "Error in ./Page1 class Page1 - caused by: Cannot read property 'name' of undefined" I assumed it would be feasible to access the Schueler instance within the HTML code.

angular typescript ionic-framework

Answer 1

Answer №1

To correctly utilize the variable, you must assign it properly. Currently, there is an open-ended variable called Schueler that is set to a new instance of Student. It may work fine with a console.log, but in order to pass it to the view, you need to assign it.

export class Page1{
   studentName:string; // element that can be assigned for viewing

   constructor(public navCtrl: NavController) {
      let Schueler = new Student('Doldi');
      this.studentName = Schueler.name;
   }
}

In your view:

<ul>
  <li> {{ studentName.name }} </li>
</ul>

You can also create an instance of the Student object within the constructor():

constructor(public navCtrl: NavController, public student: Student) { 
    this.student = student('Doldi');
}

Afterwards in the code:

<ul>
  <li> {{ student.name }} </li>
</ul>

Answer 2

To correctly utilize the variable, you must assign it properly. Currently, there is an open-ended variable called Schueler that is set to a new instance of Student. It may work fine with a console.log, but in order to pass it to the view, you need to assign it.

export class Page1{
   studentName:string; // element that can be assigned for viewing

   constructor(public navCtrl: NavController) {
      let Schueler = new Student('Doldi');
      this.studentName = Schueler.name;
   }
}

In your view:

<ul>
  <li> {{ studentName.name }} </li>
</ul>

You can also create an instance of the Student object within the constructor():

constructor(public navCtrl: NavController, public student: Student) { 
    this.student = student('Doldi');
}

Afterwards in the code:

<ul>
  <li> {{ student.name }} </li>
</ul>

Ionic/Angular 2: Issue accessing object in the Page1 class - error caused by: Unable to retrieve the 'name' property as it is undefined

Answer №1

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