Infinite scroll in Angular Treegrid component

27 Sep 20239 minutes to read

Infinite scrolling is used to load a huge amount of data without degrading the Tree Grid performance. This feature works like the lazy loading concept, which means the buffer data is loaded only when the scrollbar reaches the end of the scroller.

To use Infinite scrolling, set enableInfiniteScrolling property as true and inject the InfiniteScroll module in the treegrid.

• In this feature, Tree Grid will not make a new data request when you visit the same page again.

app.component.ts

import { Component, OnInit } from '@angular/core';
import { dataSource, virtualData } from './datasource';

@Component({
    selector: 'app-container',
    template: `<ejs-treegrid #treegrid [dataSource]='data' [enableInfiniteScrolling]=true height=317 [pageSettings]='pageSettings' childMapping='Crew' [treeColumnIndex]='1' >
        <e-columns>
            <e-column field='TaskID' headerText='Player Jersey' width='120' textAlign='Right'></e-column>
            <e-column field='FIELD1' headerText='Player Name' width='120'></e-column>
            <e-column field='FIELD2' headerText='Year' width='100' textAlign='Right'></e-column>
            <e-column field='FIELD3' headerText='Stint' width='120' textAlign='Right'></e-column>
            <e-column field='FIELD4' headerText='TMID' width='120' textAlign='Right'></e-column>
        </e-columns>
</ejs-treegrid>`
})
export class AppComponent implements OnInit {

    public data?: Object[];
    public pageSettings?: Object;

    ngOnInit(): void {
        dataSource();
        this.data = virtualData;
        this.pageSettings = {pageSize: 30};
    }
}

app.module.ts

import { NgModule,ViewChild } from '@angular/core';
import { BrowserModule } from '@angular/platform-browser';
import { TreeGridModule } from '@syncfusion/ej2-angular-treegrid';
import { PageService, InfiniteScrollService } from '@syncfusion/ej2-angular-treegrid';
import { AppComponent } from './app.component';

/**
 * Module
 */
@NgModule({
    imports: [
        BrowserModule,
        TreeGridModule
    ],
    declarations: [AppComponent],
    bootstrap: [AppComponent],
    providers: [PageService,
        InfiniteScrollService]
})
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);

InitialBlocks

You can define the initial loading pages count by using infiniteScrollSettings.initialBlocks property. By default, this feature loads three pages in initial rendering.

In the below demo, we have changed this property value to load five page records instead of three.

app.component.ts

import { Component, OnInit} from '@angular/core';
import { dataSource, virtualData } from './datasource';

@Component({
    selector: 'app-container',
    template: `<ejs-treegrid #treegrid [dataSource]='data' [enableInfiniteScrolling]=true height=317 [infiniteScrollSettings]='infiniteScrollSettings' [pageSettings]='pageSettings' childMapping='Crew' [treeColumnIndex]='1' >
        <e-columns>
            <e-column field='TaskID' headerText='Player Jersey' width='120' textAlign='Right'></e-column>
            <e-column field='FIELD1' headerText='Player Name' width='120'></e-column>
            <e-column field='FIELD2' headerText='Year' width='100' textAlign='Right'></e-column>
            <e-column field='FIELD3' headerText='Stint' width='120' textAlign='Right'></e-column>
            <e-column field='FIELD4' headerText='TMID' width='120' textAlign='Right'></e-column>
        </e-columns>
</ejs-treegrid>`
})
export class AppComponent implements OnInit {

    public data?: Object[];
    public pageSettings?: Object;
    public infiniteScrollSettings?: Object;

    ngOnInit(): void {
        dataSource();
        this.data = virtualData;
        this.pageSettings = {pageSize: 30};
        this.infiniteScrollSettings = { initialBlocks: 5};
    }
}

app.module.ts

import { NgModule,ViewChild } from '@angular/core';
import { BrowserModule } from '@angular/platform-browser';
import { TreeGridModule } from '@syncfusion/ej2-angular-treegrid';
import { PageService, InfiniteScrollService } from '@syncfusion/ej2-angular-treegrid';
import { AppComponent } from './app.component';

/**
 * Module
 */
@NgModule({
    imports: [
        BrowserModule,
        TreeGridModule
    ],
    declarations: [AppComponent],
    bootstrap: [AppComponent],
    providers: [PageService,
        InfiniteScrollService]
})
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);

Cache Mode

Cache is used to store the loaded rows object in the Tree Grid instance which can be reused for creating the row elements whenever you scroll to already visited page. Also, this mode maintains row elements based on the infiniteScrollSettings.maxBlocks count value, once this limit exceeds then it will remove row elements from DOM for new rows.

To enable the cache mode in Infinite scrolling, set infiniteScrollSettings.enableCache property as true.

app.component.ts

import { Component, OnInit } from '@angular/core';
import { dataSource, virtualData } from './datasource';

@Component({
    selector: 'app-container',
    template: `<ejs-treegrid #treegrid [dataSource]='data' [enableInfiniteScrolling]=true height=317 [infiniteScrollSettings]='infiniteScrollSettings' [pageSettings]='pageSettings' childMapping='Crew' [treeColumnIndex]='1' >
        <e-columns>
            <e-column field='TaskID' headerText='Player Jersey' width='120' textAlign='Right'></e-column>
            <e-column field='FIELD1' headerText='Player Name' width='120'></e-column>
            <e-column field='FIELD2' headerText='Year' width='100' textAlign='Right'></e-column>
            <e-column field='FIELD3' headerText='Stint' width='120' textAlign='Right'></e-column>
            <e-column field='FIELD4' headerText='TMID' width='120' textAlign='Right'></e-column>
        </e-columns>
</ejs-treegrid>`
})
export class AppComponent implements OnInit {

    public data?: Object[];
    public pageSettings?: Object;
    public infiniteScrollSettings?: Object;

    ngOnInit(): void {
        dataSource();
        this.data = virtualData;
        this.pageSettings = {pageSize: 30};
        this.infiniteScrollSettings = { enableCache: true};
    }
}

app.module.ts

import { NgModule,ViewChild } from '@angular/core';
import { BrowserModule } from '@angular/platform-browser';
import { TreeGridModule } from '@syncfusion/ej2-angular-treegrid';
import { PageService, InfiniteScrollService } from '@syncfusion/ej2-angular-treegrid';
import { AppComponent } from './app.component';

/**
 * Module
 */
@NgModule({
    imports: [
        BrowserModule,
        TreeGridModule
    ],
    declarations: [AppComponent],
    bootstrap: [AppComponent],
    providers: [PageService,
        InfiniteScrollService]
})
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);

Limitations for Virtualization

• Due to the element height limitation in browsers, the maximum number of records loaded by the tree grid is limited due to the browser capability.
• Initial loading rows total height must be greater than the viewport height.
• Cell selection will not be persisted in cache mode.
• Infinite scrolling is not compatible with batch editing, cell editing, detail template and hierarchy features.
• The aggregated information and total group items are displayed based on the current view items. To get these information regardless of the view items, refer to the
• Programmatic selection using the selectRows and selectRow method is not supported in infinite scrolling.

You can refer to our Angular Tree Grid feature tour page for its groundbreaking feature representations. You can also explore our Angular Tree Grid example to knows how to present and manipulate data.