Executing a function in Ionic 2 when the selected value is altered

Question

Executing a function in Ionic 2 when the selected value is altered

I recently started learning about Ionic 2 and spent time going through the documentation. I tried implementing this code to get the current select value when it changes and print it to the console.

page.html

<ion-select #D ionChange="onUpdate(D.value)"> 
                    <ion-option value="x">X</ion-option>
                    <ion-option value="y">Y</ion-option>
</ion-select>

page.ts

public DValue:String;
onUpdate(DValue) {
     console.log(DValue);
}

Unfortunately, nothing related to this is showing up in the console. Is there something missing in the binding process?

angular typescript ionic-framework ionic2 ionic3

Answer 1

Answer №1

Try this alternative

<ion-select #C ionChange="onChange(C.value)"> 
  ...
</ion-select>

To handle the event properly, you should use the parentheses like this:

<ion-select #C (ionChange)="onChange(C.value)">
  ...
</ion-select>

Answer 2

Try this alternative

<ion-select #C ionChange="onChange(C.value)"> 
  ...
</ion-select>

To handle the event properly, you should use the parentheses like this:

<ion-select #C (ionChange)="onChange(C.value)">
  ...
</ion-select>

Answer 3

Answer №2

Instead of following this method

<ion-select #C (ionChange)="onChange(C.value)">
  ...
</ion-select>

You also have the option to use "$event" to retrieve the value

<ion-select #C (ionChange)="onChange($event)">
  ...
</ion-select>

Answer 4

Instead of following this method

<ion-select #C (ionChange)="onChange(C.value)">
  ...
</ion-select>

You also have the option to use "$event" to retrieve the value

<ion-select #C (ionChange)="onChange($event)">
  ...
</ion-select>

Answer 5

Answer №3

When working with Ionic 4, implement the following code snippet:

<ion-select [(ngModel)]="c.value" (ngModelChange)="myFun(c.value)">
...
</ion-select>

Answer 6

When working with Ionic 4, implement the following code snippet:

<ion-select [(ngModel)]="c.value" (ngModelChange)="myFun(c.value)">
...
</ion-select>

Answer 7

Answer №4

Learn how to implement ionChange in Ionic 4 by following the official documentation guidelines.

<ion-select formControlName="item" (ionChange)="saveSettings()"></ion-select>

To prevent the ionChange event from being triggered during the initial population of data, add the emitEvent: false property to the options when patching.

this.settingsForm.patchValue(data, {emitEvent: false, onlySelf: true})

Avoid double-saving at initialization caused by ion-select firing upon patching the options. Set a global boolean variable to track initialization status and modify your save function accordingly:

await this.settings$.subscribe(async data => {
  if(this.initialLoading == 0) {
    console.log('Subscription data initializing...');
    await this.settingsForm.patchValue(data, {
      onlySelf:true,
      emitEvent:false
    });
    this.initialLoading = 1;
  } else {
    console.log('Settings were altered.');
  }
});

async saveSettings() {
  if(this.initialLoading == 1) {
    // Add your code here
  }
}

Answer 8

Learn how to implement ionChange in Ionic 4 by following the official documentation guidelines.

<ion-select formControlName="item" (ionChange)="saveSettings()"></ion-select>

To prevent the ionChange event from being triggered during the initial population of data, add the emitEvent: false property to the options when patching.

this.settingsForm.patchValue(data, {emitEvent: false, onlySelf: true})

Avoid double-saving at initialization caused by ion-select firing upon patching the options. Set a global boolean variable to track initialization status and modify your save function accordingly:

await this.settings$.subscribe(async data => {
  if(this.initialLoading == 0) {
    console.log('Subscription data initializing...');
    await this.settingsForm.patchValue(data, {
      onlySelf:true,
      emitEvent:false
    });
    this.initialLoading = 1;
  } else {
    console.log('Settings were altered.');
  }
});

async saveSettings() {
  if(this.initialLoading == 1) {
    // Add your code here
  }
}

Answer 9

Answer №5

When setting up your template

<ion-label>Priority</ion-label>
   <ion-select placeholder="Choose"  [(ngModel)]="pvalue" (ionChange)="getValue()">
    <ion-option value="a">A</ion-option>
    <ion-option value="b">B</ion-option>
 </ion-select>

In your Component.ts File

pvalue:any;
getValue(){
console.log(this.pvalue);
// Display the selected value
}

Answer 10

When setting up your template

<ion-label>Priority</ion-label>
   <ion-select placeholder="Choose"  [(ngModel)]="pvalue" (ionChange)="getValue()">
    <ion-option value="a">A</ion-option>
    <ion-option value="b">B</ion-option>
 </ion-select>

In your Component.ts File

pvalue:any;
getValue(){
console.log(this.pvalue);
// Display the selected value
}

Executing a function in Ionic 2 when the selected value is altered

Answer №1

Answer №2

Answer №3

Answer №4

Answer №5

Similar questions

TS2339: The specified property is not present on the Angular type

Utilizing Angular signals to facilitate data sharing among child components

What is the best method to condense an array or extract only the valid values?

What is the best way to display various components based on the user's device type, whether it be web

Developing a Meteor application with the powerful combination of Vue.js and Typescript

How does the type of the original array influence the inferred types of the destructured array values?

How to automatically scroll to the most recently added element in an *ngFor loop using Angular 2

Tips for repositioning the color picker

Angular is experiencing issues with form validation

Click on the header of each section in the Ng-Bootstrap accordion to expand and view its content

The ion-datetime in Ionic 4 ensures that the floating label always remains visible, even when the input

Navigating through nested objects in a combined type

Sending data to the server using AngularJS 1.x and Typescript

What is the reason for the back button appearing next to the slide menu?

Utilizing Angular 4 Typescript to create cascading drop-downs within a table

To resolve the NG0500 error during hydration, Angular is looking for an <ion-toolbar> element but instead found a comment node

Issue with retrieving JSON data in chart object: Error reading property 'length' of undefined in Angular/ng2-charts

The flexibility of adjusting the percentage in the ng-circle-progress feature

tips for showing search outcomes with Angular

Error in uploading files with Node.js, Multer, and Angular - issue with setting headers after they have already been sent