How to customize the expand and collapse icons in Angular Tree View
27 Sep 202616 minutes to read
The Angular Tree View component displays default expand and collapse icons for parent nodes. These icons can be customized to match application themes or design requirements by using the cssClass property along with custom CSS styling.
The cssClass property allows you to apply custom CSS classes to the Angular Tree View component, which can then be used to override the default expand and collapse icon styles. The Angular Tree View uses specific CSS selectors for these icons that can be targeted through custom CSS rules.
To customize the expand and collapse icons, define custom CSS classes that target the Angular Tree View’s icon elements and apply these styles using the cssClass property. The custom CSS should override the default icon fonts or background images with the desired custom icons.
The Angular Tree View renders the expand/collapse icons on .e-icon-expandable and .e-icon-collapsible elements. You can override them with any of the following approaches:
-
Custom font glyphs: Set a different
font-familyandcontentvalue to swap the built-in character glyph. -
Background image: Replace the icon with
background-imageand hide the original text viafont-size: 0. -
SVG sprite: Apply
background-imagewith an inline SVGdata:URL for vector icons that scale on high-DPI screens.
The CSS used in the sample below applies a square background-image to both states:
.accordion-tree .e-icon-expandable,
.accordion-tree .e-icon-collapsible {
background-image: url('./icons/folder.svg');
background-size: contain;
background-repeat: no-repeat;
font-size: 0;
}import { NgModule } from '@angular/core'
import { BrowserModule } from '@angular/platform-browser'
import { FormsModule } from '@angular/forms'
import { TreeViewModule } from '@syncfusion/ej2-angular-navigations'
import { Component, ViewChild } from '@angular/core';
import { TreeViewComponent } from '@syncfusion/ej2-angular-navigations';
@Component({
imports: [
FormsModule, TreeViewModule
],
standalone: true,
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')
public tree?: TreeViewComponent;
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";
}@import 'node_modules/@syncfusion/ej2-base/styles/material3.css';
@import 'node_modules/@syncfusion/ej2-inputs/styles/material3.css';
@import 'node_modules/@syncfusion/ej2-buttons/styles/material3.css';
@import 'node_modules/@syncfusion/ej2-angular-base/styles/material3.css';
@import 'node_modules/@syncfusion/ej2-angular-navigations/styles/material3.css';
@import 'node_modules/@syncfusion/ej2-angular-inputs/styles/material3.css';
.custom .e-list-item .e-icons {
font-family: "Customize-icon";
}
.custom.e-treeview .e-list-item div.e-icons.e-icon-expandable::before,
.custom.e-treeview .e-list-item div.e-icons.e-icon-collapsible::before {
content: '\e700';
font-size: 12px;
}
@font-face {
font-family: 'Customize-icon';
src: url(data:application/x-font-ttf;charset=utf-8;base64,AAEAAAAKAIAAAwAgT1MvMj0gSRcAAAEoAAAAVmNtYXDnEOdaAAABjAAAADhnbHlmcYqIngAAAcwAAAD8aGVhZBWT124AAADQAAAANmhoZWEHmANtAAAArAAAACRobXR4C9AAAAAAAYAAAAAMbG9jYQBAAH4AAAHEAAAACG1heHABEAAxAAABCAAAACBuYW1l/qscPAAAAsgAAAJ5cG9zdIPGFvoAAAVEAAAAVgABAAADUv9qAFoEAAAA//8D6QABAAAAAAAAAAAAAAAAAAAAAwABAAAAAQAAIKcGUl8PPPUACwPoAAAAANlGSVAAAAAA2UZJUAAAAAAD6QPpAAAACAACAAAAAAAAAAEAAAADACUAAwAAAAAAAgAAAAoACgAAAP8AAAAAAAAAAQPwAZAABQAAAnoCvAAAAIwCegK8AAAB4AAxAQIAAAIABQMAAAAAAAAAAAAAAAAAAAAAAAAAAAAAUGZFZABA5wDnAQNS/2oAWgPpAJYAAAABAAAAAAAABAAAAAPoAAAD6AAAAAAAAgAAAAMAAAAUAAMAAQAAABQABAAkAAAABAAEAAEAAOcB//8AAOcA//8AAAABAAQAAAABAAIAAAAAAEAAfgADAAAAAAPpA+kACAAWACQAAAEhFSEHMzcnIyUWEAcGICcmEDc+ATIWBQYQFxYgNzYQJy4BIgYCMf6kAWqUqMK8rgF+goKK/qCEfn5Coquf/amRkZoBkpqRkUq3xLcCKmSTybt4if6ghYKChQFgiUJBQRma/m6akZGaAZKaSElJAAMAAAAAA+gD6QAGABQAIgAAASMXNyMRIyUWEAcGICcmEDc+ATIWBQYQFxYgNzYQJy4BIgYBvrLp6JmGAW6BgYf+oYiBgUGhqqH9qZOTmgGOmpOTSrbCtgGy6ekBbwuI/qGHgYGIAV6IQEFBFpr+cZmTk5oBj5lKSUkAAAAAABIA3gABAAAAAAAAAAEAAAABAAAAAAABAA4AAQABAAAAAAACAAcADwABAAAAAAADAA4AFgABAAAAAAAEAA4AJAABAAAAAAAFAAsAMgABAAAAAAAGAA4APQABAAAAAAAKACwASwABAAAAAAALABIAdwADAAEECQAAAAIAiQADAAEECQABABwAiwADAAEECQACAA4ApwADAAEECQADABwAtQADAAEECQAEABwA0QADAAEECQAFABYA7QADAAEECQAGABwBAwADAAEECQAKAFgBHwADAAEECQALACQBdyBDdXN0b21pemUtaWNvblJlZ3VsYXJDdXN0b21pemUtaWNvbkN1c3RvbWl6ZS1pY29uVmVyc2lvbiAxLjBDdXN0b21pemUtaWNvbkZvbnQgZ2VuZXJhdGVkIHVzaW5nIFN5bmNmdXNpb24gTWV0cm8gU3R1ZGlvd3d3LnN5bmNmdXNpb24uY29tACAAQwB1AHMAdABvAG0AaQB6AGUALQBpAGMAbwBuAFIAZQBnAHUAbABhAHIAQwB1AHMAdABvAG0AaQB6AGUALQBpAGMAbwBuAEMAdQBzAHQAbwBtAGkAegBlAC0AaQBjAG8AbgBWAGUAcgBzAGkAbwBuACAAMQAuADAAQwB1AHMAdABvAG0AaQB6AGUALQBpAGMAbwBuAEYAbwBuAHQAIABnAGUAbgBlAHIAYQB0AGUAZAAgAHUAcwBpAG4AZwAgAFMAeQBuAGMAZgB1AHMAaQBvAG4AIABNAGUAdAByAG8AIABTAHQAdQBkAGkAbwB3AHcAdwAuAHMAeQBuAGMAZgB1AHMAaQBvAG4ALgBjAG8AbQAAAAACAAAAAAAAAAoAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAAMBAgEDAQQAFy1hcnJvdy1jaXJjbGUtcmlnaHQtXzAxEi1hcnJvdy1jaXJjbGUtZG93bgAAAAA=) format('truetype');
font-weight: normal;
font-style: normal;
}
#treeparent {
display: block;
max-width: 400px;
max-height: 330px;
margin: auto;
overflow: auto;
border: 1px solid #dddddd;
border-radius: 3px;
}import { bootstrapApplication } from '@angular/platform-browser';
import { AppComponent } from './app.component';
bootstrapApplication(AppComponent).catch((err) => console.error(err));