How to bind select element to an object in Angular ?

AngularJS is a JavaScript-based framework. It can be used by adding it to an HTML page using a <script> tag. AngularJS helps in extending the HTML attributes with the help of directives and binding of data to the HTML with expressions. An Angular service is a broad category that consists of any value, function, or feature that an application needs. A service is a class with a narrow and well-defined purpose. In this article, we will see how to bind a select element to an object in AngularJS. The process of binding a select element to an object helps in associating the selected value with a property in our component class.

Steps to bind select element to object: The below steps will be followed for binding the select element to the object in Angular:

Step 1: Create a new Angular project and install the necessary dependencies

ng new my-app
cd my-app

Step 2: Create a new Angular component

ng generate component my-component

This will create a new directory called “my-component” in your project’s “src/app” directory, along with the necessary files for an Angular component.

Step 3: Create an interface or class to define the structure of the options

export interface Option {
  value: string;
  displayText: string;
}

Step 4: Define an array of options in your component

export class MyComponentComponent {
  options = [
    { id: 1, name: 'Java' },
    { id: 2, name: 'C++' },
    { id: 3, name: 'Python' }
  ];
  selectedOption: any;
}

Step 5: Use the ngFor directive to generate the options in the select element

<select [(ngModel)]="selectedOption">
  <option *ngFor="let option of options" 
             [ngValue]="option">
             {{option.name}}
  </option>
</select>

Step 6: Use the selected option in your component

<p>You selected: {{ selectedOption | json }}</p>

We will understand the above concept with the help of suitable approaches & will understand its implementation through the illustration.

Approach 1: In this approach, we are using the ngValue directive to bind the entire object to the value attribute of the option element. This approach requires a compareWith function to be defined to properly compare the selected option with the options in the array.

Example 1: Below example demonstrates the binding of the select element to an object in angular.

• app.module.ts

• my-component-component.html

• my-component-component.ts

• app.component.html

Output:

 

Approach 2: In this approach, we are using the value attribute of the option element to bind the entire object to the selectedOption property. This approach does not require a compareWith function and is simpler to set up.

Example 2: This is another example that demonstrates the binding of the select element to an object in Angular.

• app.module.ts

• select-object.component.html

• select-object-component.ts

• app.component.html

Output:

 

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Article Tags :

• AngularJS
• Web Technologies
• AngularJS-Questions