Customize the expand and collapse icons in Angular Treeview component

13 Feb 202311 minutes to read

You can customize TreeView expand and collapse icons by using the cssClass property of TreeView.
Refer to the sample to customize expand/collapse icons.

app.component.ts

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

@Component({
    selector: 'app-container',
    // specifies the template string for the TreeView component
    template: `<div id='treeparent'><ejs-treeview id='treeelement' [fields]='field' [cssClass]='cssClass'></ejs-treeview></div>`
})
export class AppComponent {
    @ViewChild('samples')
    constructor() {
    }
    // defined the array of data
    public hierarchicalData: Object[] = [
            { id: '01', name: 'Local Disk(C:)', expanded: true,
        subChild: [
            {
                id: '01-01', name: 'Program Files',
                subChild: [
                    { id: '01-01-01', name: '7-Zip' },
                    { id: '01-01-02', name: 'Git' },
                    { id: '01-01-03', name: 'IIS Express' },
                ]
            },
            {
                id: '01-02', name: 'Users', expanded: true,
                subChild: [
                    { id: '01-02-01', name: 'Smith' },
                    { id: '01-02-02', name: 'Public' },
                    { id: '01-02-03', name: 'Admin' },
                ]
            },
            {
                id: '01-03', name: 'Windows',
                subChild: [
                    { id: '01-03-01', name: 'Boot' },
                    { id: '01-03-02', name: 'FileManager' },
                    { id: '01-03-03', name: 'System32' },
                ]
            },
        ]
    },
    {
        id: '02', name: 'Local Disk(D:)',
        subChild: [
            {
                id: '02-01', name: 'Personals',
                subChild: [
                    { id: '02-01-01', name: 'My photo.png' },
                    { id: '02-01-02', name: 'Rental document.docx' },
                    { id: '02-01-03', name: 'Pay slip.pdf' },
                ]
            },
            {
                id: '02-02', name: 'Projects',
                subChild: [
                    { id: '02-02-01', name: 'ASP Application' },
                    { id: '02-02-02', name: 'TypeScript Application' },
                    { id: '02-02-03', name: 'React Application' },
                ]
            },
            {
                id: '02-03', name: 'Office',
                subChild: [
                    { id: '02-03-01', name: 'Work details.docx' },
                    { id: '02-03-02', name: 'Weekly report.docx' },
                    { id: '02-03-03', name: 'Wish list.csv' },
                ]
            },
        ]
    },
    {
        id: '03', name: 'Local Disk(E:)', icon: 'folder',
        subChild: [
            {
                id: '03-01', name: 'Pictures',
                subChild: [
                    { id: '03-01-01', name: 'Wind.jpg' },
                    { id: '03-01-02', name: 'Stone.jpg' },
                    { id: '03-01-03', name: 'Home.jpg' },
                ]
            },
            {
                id: '03-02', name: 'Documents',
                    subChild: [
                    { id: '03-02-01', name: 'Environment Pollution.docx' },
                    { id: '03-02-02', name: 'Global Warming.ppt' },
                    { id: '03-02-03', name: 'Social Network.pdf' },
                ]
            },
            {
                id: '03-03', name: 'Study Materials',
                subChild: [
                    { id: '03-03-01', name: 'UI-Guide.pdf' },
                    { id: '03-03-02', name: 'Tutorials.zip' },
                    { id: '03-03-03', name: 'TypeScript.7z' },
                ]
            },
        ]
    }
    ];
    // maps the appropriate column to fields property
    public field: Object = { dataSource: this.hierarchicalData, id: 'id', text: 'name', child: 'subChild' };
    // set the Multi Selection option to TreeView
    public cssClass: string = "custom";
}

app.module.ts

import { NgModule } from '@angular/core';
import { BrowserModule } from '@angular/platform-browser';
import { FormsModule } from '@angular/forms';
import { AppComponent } from './app.component';
import { TreeViewModule } from '@syncfusion/ej2-angular-navigations';
/**
 * Module
 */
@NgModule({
    imports: [
        BrowserModule,FormsModule,TreeViewModule
    ],
    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';

enableProdMode();
platformBrowserDynamic().bootstrapModule(AppModule);