How to implement dropdown with dynamic levels in Angular?

To implement a dropdown with dynamic levels (nested dropdowns) in Angular, you can use Angular’s template-driven or reactive forms along with Angular’s component structure. Here’s a step-by-step guide on how to create such a dropdown:

Set Up Your Angular Project:
If you haven’t already, create a new Angular project using the Angular CLI:

1	ng new dynamic-dropdown

Create a Component:
Generate a new Angular component for your dynamic dropdown:

1	ng generate component dynamic-dropdown

Define the Data Structure:
Decide on the data structure that will represent the levels of your dropdown. For this example, let’s assume you have a list of categories, each with a name and an optional nested list of subcategories.
Create the HTML Template:
In your component’s HTML file (dynamic-dropdown.component.html), create the dropdown structure using Angular’s template syntax. You’ll use *ngFor to loop through the levels of the dropdown.

<option value="">{{ category.name }}</option>

</option>

</select>

</div>

Create the Component Logic:
In your component file (dynamic-dropdown.component.ts), define the data structure for categories and subcategories and initialize the selected category. You can also add a function to handle changes in the selected category.

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

@Component({

selector: 'app-dynamic-dropdown',

templateUrl: './dynamic-dropdown.component.html',

styleUrls: ['./dynamic-dropdown.component.css']

})

export class DynamicDropdownComponent {

categories = [

{

name: 'Category 1',

subcategories: [

{ name: 'Subcategory 1.1' },

{ name: 'Subcategory 1.2' }

]

{

name: 'Category 2',

subcategories: [

{ name: 'Subcategory 2.1' },

{ name: 'Subcategory 2.2' }

]

}

];

selectedCategory: any;

onCategoryChange() {

// Handle the change of the selected category

console.log(this.selectedCategory);

}

Add FormsModule:
Ensure that you’ve imported and added the FormsModule from @angular/forms to your app.module.ts:

import { FormsModule } from '@angular/forms';

@NgModule({

declarations: [

// ...

imports: [

BrowserModule,

FormsModule, // Add this line

// ...

bootstrap: [AppComponent]

})

export class AppModule { }

Include the Component:
Finally, include your app-dynamic-dropdown component in your application’s HTML file (e.g., app.component.html) to render the dynamic dropdown.

<div>

<h1>Dynamic Dropdown Example</h1>

<app-dynamic-dropdown></app-dynamic-dropdown>

</div>

Styling and Further Customization:
You can style your dropdown and add more features as needed based on your application requirements.

With these steps, you’ll have a dynamic dropdown with multiple levels in your Angular application. The example provided assumes a simple data structure, but you can adapt it to more complex scenarios with additional levels or data sources.