Form support in Angular Drop down list component

27 Sep 20237 minutes to read

The DropDownList supports both the reactive and template-driven form-building technologies.

Template-Driven Forms

The template-drive forms uses the ng directives in view to handle the forms controls. To enable the template-driven, import the FormsModule into corresponding app component.

For more details about template-driven Forms refer to:https://angular.io/guide/forms#template-driven-forms.

Mention the name attribute to DropDownList element which will be used to identify the form element. To register an DropDownList element to ngForm, give the ngModel to it so the FormsModule will automatically detect the DropDownList as a form element. After that, the DropDownList value will be selected based on the ngModel value.

The following example demonstrates how to achieve a two-way data binding.

app.component.ts

import { Component, OnInit } from '@angular/core';
import { FormsModule } from '@angular/forms';
import { BrowserModule } from '@angular/platform-browser';

@Component({
    selector: 'app-root',
    templateUrl: 'form-support.html'
})
export class AppComponent {
    // defined the array of data
    public skillset: string[] = [
        'ASP.NET', 'ActionScript', 'Basic',
        'C++' , 'C#' , 'dBase' , 'Delphi' ,
        'ESPOL' , 'F#' , 'FoxPro' , 'Java',
        'J#' , 'Lisp' , 'Logo' , 'PHP'
    ];
    public placeholder: String = 'e.g: ActionScript';

    constructor() {
    }
        skillForm = {
            skillname: null,
            sname: '',
            smail: ''
        };
}

app.module.ts

import { NgModule } from '@angular/core';
import { BrowserModule } from '@angular/platform-browser';
import { FormsModule, ReactiveFormsModule } from '@angular/forms';
import { AppComponent } from './app.component';
import { DropDownListModule } from '@syncfusion/ej2-angular-dropdowns';
import { ButtonModule } from '@syncfusion/ej2-angular-buttons';
/**
 * Module
 */
@NgModule({
    imports: [
        BrowserModule,FormsModule, ReactiveFormsModule, DropDownListModule, ButtonModule
    ],
    declarations: [AppComponent],
    bootstrap: [AppComponent]
})
export class AppModule { }

main.ts

import { platformBrowserDynamic } from '@angular/platform-browser-dynamic';
import { enableProdMode } from '@angular/core';
import { AppModule } from './app.module';

import 'zone.js';
enableProdMode();
platformBrowserDynamic().bootstrapModule(AppModule);

Reactive Forms

The reactive forms uses the reactive model-driven technique to handle form data between component and view, due to that we also call it as the model-driven forms. It’s listen the form data changes between App component and view also returns the valid states and values of form elements.

For more details about Reactive Forms refer: https://angular.io/guide/reactive-forms.

For the reactive forms you should import a ReactiveFormsModule into app module as well as the FormGroup,FormControl should be imported to app component. The FormGroup is used to declare formGroupName for the form and the FormControl is used to declare formControlName for form controls.

You can declare the formControlName to DropDownList as usual. then,you must create a value object to the FormGroup and each value will be the default value of the form control.

The following example demonstrates how to use the reactive forms.

app.component.ts

import { Component, OnInit, Inject } from '@angular/core';
import { FormBuilder, FormGroup, Validators } from '@angular/forms';
import { BrowserModule } from '@angular/platform-browser';

@Component({
    selector: 'app-root',
    templateUrl: 'reactive-form.html'
})
export class AppComponent {
    // defined the array of data
    public skillset: string[] = [
        'ASP.NET', 'ActionScript', 'Basic',
        'C++' , 'C#' , 'dBase' , 'Delphi' ,
        'ESPOL' , 'F#' , 'FoxPro' , 'Java',
        'J#' , 'Lisp' , 'Logo' , 'PHP'
    ];
    public placeholder: String = 'e.g: ActionScript';
    skillForm?: FormGroup| any;
    fb: FormBuilder;
    constructor(@Inject(FormBuilder) private builder: FormBuilder) {
        this.fb = builder;
        this.createForm();
    }
    createForm() {
        this.skillForm = this.fb.group({
            skillname: ['', Validators.required],
            sname: ['', Validators.required],
            smail: ['', Validators.required]
        });
    }
}

app.module.ts

import { NgModule } from '@angular/core';
import { BrowserModule } from '@angular/platform-browser';
import { FormsModule, ReactiveFormsModule } from '@angular/forms';
import { AppComponent } from './app.component';
import { DropDownListModule } from '@syncfusion/ej2-angular-dropdowns';
import { ButtonModule } from '@syncfusion/ej2-angular-buttons';
/**
 * Module
 */
@NgModule({
    imports: [
        BrowserModule,FormsModule, ReactiveFormsModule, DropDownListModule, ButtonModule
    ],
    declarations: [AppComponent],
    bootstrap: [AppComponent]
})
export class AppModule { }

main.ts

import { platformBrowserDynamic } from '@angular/platform-browser-dynamic';
import { enableProdMode } from '@angular/core';
import { AppModule } from './app.module';

import 'zone.js';
enableProdMode();
platformBrowserDynamic().bootstrapModule(AppModule);