Getting started with Angular TreeView component

This section explains the steps required to create a simple Angular TreeView component, and configure its available functionalities

Setup Angular Environment

You can use Angular CLI to setup your Angular applications. To install Angular CLI use the following command.

npm install -g @angular/cli

Create an Angular Application

Start a new Angular application using below Angular CLI command.

ng new my-app
cd my-app

Installing Syncfusion Treeview Package

Syncfusion packages are distributed in npm as @syncfusion scoped packages. You can get all the Angular Syncfusion package from npm link.

Currently, Syncfusion provides two types of package structures for Angular components,

1. Ivy library distribution package format
2. Angular compatibility compiler(Angular’s legacy compilation and rendering pipeline) package.

Ivy library distribution package

Syncfusion Angular packages(>=20.2.36) has been moved to the Ivy distribution to support the Angular Ivy rendering engine and the package are compatible with Angular version 12 and above. To download the package use the below command.

Add @syncfusion/ej2-angular-navigations package to the application.

npm install @syncfusion/ej2-angular-navigations --save

Angular compatibility compiled package(ngcc)

For Angular version below 12, you can use the legacy (ngcc) package of the Syncfusion Angular components. To download the ngcc package use the below.

Add @syncfusion/ej2-angular-navigations@ngcc package to the application.

npm install @syncfusion/ej2-angular-navigations@ngcc --save

To mention the ngcc package in the package.json file, add the suffix -ngcc with the package version as below.

@syncfusion/ej2-angular-navigations:"20.2.38-ngcc"

Note: If the ngcc tag is not specified while installing the package, the Ivy Library Package will be installed and this package will throw a warning.

Registering Treeview Module

Import Treeview module into Angular application(app.module.ts) from the package @syncfusion/ej2-angular-navigations [src/app/app.module.ts].

import { NgModule } from '@angular/core';
import { BrowserModule } from '@angular/platform-browser';
// import Treeview component Module
import { TreeViewModule } from '@syncfusion/ej2-angular-navigations';
import { AppComponent }  from './app.component';

@NgModule({
  //declaration of Treeview module into NgModule
  imports:      [ BrowserModule, TreeViewModule ],
  declarations: [ AppComponent ],
  bootstrap:    [ AppComponent ]
})
export class AppModule { }

Adding CSS Reference

• Add Treeview component’s styles as given below in styles.css.

@import "../node_modules/@syncfusion/ej2-base/styles/material.css";
@import "../node_modules/@syncfusion/ej2-angular-navigations/styles/material.css";
@import "../node_modules/@syncfusion/ej2-inputs/styles/material.css";
@import "../node_modules/@syncfusion/ej2-buttons/styles/material.css";

Note: If you want to refer the combined component styles, please make use of our CRG (Custom Resource Generator) in your application.

Add Treeview component

Modify the template in [src/app/app.component.ts] file to render the Treeview component. Add the Angular Treeview by using <ejs-treeview> selector in template section of the app.component.ts file.

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

@Component({
  selector: 'app-root',
  template: `<ejs-treeview id='treeelement' ></ejs-treeview>`
})
export class AppComponent {}

Binding data source

TreeView can load data either from local data sources or remote data services. This can be done using the dataSource property that is a member of the fields property. The dataSource property supports array of JavaScript objects and DataManager. Here, an array of JSON values is passed to the TreeView component.

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

@Component({
selector: 'app-root',
template: `<ejs-treeview id='treeelement' [fields]='field'></ejs-treeview>`,
encapsulation: ViewEncapsulation.None
})
export class AppComponent {
constructor() {
}
// defined the array of data
 public hierarchicalData: Object[] = [
    { id: '01', name: 'Music', expanded: true,
        subChild: [
            {id: '01-01', name: 'Gouttes.mp3'},
                  ]
    },
    {
        id: '02', name: 'Videos',
        subChild: [
            {id: '02-01', name: 'Naturals.mp4'},
            {id: '02-02', name: 'Wild.mpeg'}
    ]
    },
    {
        id: '03', name: 'Documents',
        subChild: [
            {id: '03-01', name: 'Environment Pollution.docx'},
            {id: '03-02', name: 'Global Water, Sanitation, & Hygiene.docx'},
            {id: '03-03', name: 'Global Warming.ppt'},
            {id: '03-02', name: 'Social Network.pdf'},
            {id: '03-03', name: 'Youth Empowerment.pdf'},
        ]
    }
];
public field:Object ={ dataSource: this.hierarchicalData, id: 'id', text: 'name', child: 'subChild' };
}

Run the application

Use the following command to run the application in browser.

ng serve --open

The output will appear as follows.

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

@Component({
selector: 'app-container',
template: `<div id='treeparent'><ejs-treeview id='treeelement' [fields]='field'></ejs-treeview></div>`
})
export class AppComponent {
constructor() {
}
// defined the array of data
public hierarchicalData: Object[] = [
   { id: '01', name: 'Music', expanded: true,
        subChild: [
            {id: '01-01', name: 'Gouttes.mp3'},
                  ]
    },
    {
        id: '02', name: 'Videos',
        subChild: [
            {id: '02-01', name: 'Naturals.mp4'},
            {id: '02-02', name: 'Wild.mpeg'}
    ]
    },
    {
        id: '03', name: 'Documents',
        subChild: [
            {id: '03-01', name: 'Environment Pollution.docx'},
            {id: '03-02', name: 'Global Water, Sanitation, & Hygiene.docx'},
            {id: '03-03', name: 'Global Warming.ppt'},
            {id: '03-02', name: 'Social Network.pdf'},
            {id: '03-03', name: 'Youth Empowerment.pdf'},
        ]
    }
];
public field:Object ={ dataSource: this.hierarchicalData, id: 'id', text: 'name', child: 'subChild' };
}

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 { }

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

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

You can also explore our Angular TreeView example to knows how to present and manipulate data.

See Also

• How to customize treeview as accordion
• How to set tooltip for treeview nodes
• How to filter nodes in treeview
• How to get all the child nodes through parentID