Scrolling in Angular Treegrid component

17 Nov 202213 minutes to read

The scrollbar will be displayed in the treegrid when content exceeds the element width or height. The vertical and horizontal scrollbars will be displayed based on the following criteria:

  • The vertical scrollbar appears when the total height of rows present in the treegrid exceeds its element height.
  • The horizontal scrollbar appears when the sum of columns width exceeds the treegrid element width.
  • The height and width are used to set the treegrid height and width, respectively.

The default value for height and width is auto.

Set width and height

To specify the width and height of the scroller in the pixel, set the pixel value to a number.

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

@Component({
    selector: 'app-container',
    template: `<ejs-treegrid [dataSource]='data' height='315' width='400' [treeColumnIndex]='1'  childMapping='subtasks' >
        <e-columns>
                    <e-column field='taskID' headerText='Task ID' textAlign='Right' width=90></e-column>
                    <e-column field='taskName' headerText='Task Name' textAlign='Left' width=180></e-column>
                    <e-column field='startDate' headerText='Start Date' textAlign='Right' format='yMd' width=120></e-column>
                    <e-column field='duration' headerText='Duration' textAlign='Right' width=110></e-column>
        </e-columns>
                </ejs-treegrid>`
})
export class AppComponent implements OnInit {

    public data: Object[];

    ngOnInit(): void {
        this.data = sampleData;
    }
}
import { NgModule,ViewChild } from '@angular/core';
import { BrowserModule } from '@angular/platform-browser';
import { TreeGridModule } from '@syncfusion/ej2-angular-treegrid';
import { PageService, SortService, FilterService } from '@syncfusion/ej2-angular-treegrid';
import { AppComponent } from './app.component';
import {ButtonModule} from '@syncfusion/ej2-angular-buttons';

/**
 * Module
 */
@NgModule({
    imports: [
        BrowserModule,
        TreeGridModule,
        ButtonModule
    ],
    declarations: [AppComponent],
    bootstrap: [AppComponent],
    providers: [PageService,
                SortService,
                FilterService]
})
export class AppModule { }
import { platformBrowserDynamic } from '@angular/platform-browser-dynamic';
import { enableProdMode } from '@angular/core';
import { AppModule } from './app.module';

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

Responsive with parent container

Specify the width and height as 100% to make the treegrid element fill its parent container.
Setting the height to 100% requires the treegrid parent element to have explicit height.

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

@Component({
    selector: 'app-container',
    template: `
    <div style="height: 350px">
        <ejs-treegrid [dataSource]='data' height='100%' width='100%' [treeColumnIndex]='1'  childMapping='subtasks' >
            <e-columns>
                    <e-column field='taskID' headerText='Task ID' textAlign='Right' width=90></e-column>
                    <e-column field='taskName' headerText='Task Name' textAlign='Left' width=180></e-column>
                    <e-column field='startDate' headerText='Start Date' textAlign='Right' format='yMd' width=120></e-column>
                    <e-column field='duration' headerText='Duration' textAlign='Right' width=110></e-column>
            </e-columns>
        </ejs-treegrid>
    </div>  
    `
})
export class AppComponent implements OnInit {

    public data: Object[];

    ngOnInit(): void {
        this.data = sampleData;
    }
}
import { NgModule,ViewChild } from '@angular/core';
import { BrowserModule } from '@angular/platform-browser';
import { TreeGridModule } from '@syncfusion/ej2-angular-treegrid';
import { PageService, SortService, FilterService } from '@syncfusion/ej2-angular-treegrid';
import { AppComponent } from './app.component';
import {ButtonModule} from '@syncfusion/ej2-angular-buttons';

/**
 * Module
 */
@NgModule({
    imports: [
        BrowserModule,
        TreeGridModule,
        ButtonModule
    ],
    declarations: [AppComponent],
    bootstrap: [AppComponent],
    providers: [PageService,
                SortService,
                FilterService]
})
export class AppModule { }
import { platformBrowserDynamic } from '@angular/platform-browser-dynamic';
import { enableProdMode } from '@angular/core';
import { AppModule } from './app.module';

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

Scroll to selected row

Scroll the tree grid content to the selected row position by using the rowSelected event.

import { RowSelectEventArgs } from '@syncfusion/ej2-treegrid';
import { Component, OnInit, ViewChild } from '@angular/core';
import { sampleData } from './datasource';
import { TreeGridComponent  } from '@syncfusion/ej2-angular-treegrid';
import { NumericTextBoxComponent } from '@syncfusion/ej2-angular-inputs';

@Component({
    selector: 'app-container',
    template: `
    <ejs-numerictextbox #numerictext  min="0" max="50" width='200' [showSpinButton]='false' format= 'N' value="0" placeHolder='Enter index to select a row' (change)='onChange($event)' ></ejs-numerictextbox>

    <ejs-treegrid #treegrid [dataSource]='data' height='260' width='100%' [treeColumnIndex]='1'  childMapping='subtasks' (rowSelected)='rowSelected($event)'[selectedRowIndex]='0'>
        <e-columns>
                    <e-column field='taskID' headerText='Task ID' textAlign='Right' width=90></e-column>
                    <e-column field='taskName' headerText='Task Name' textAlign='Left' width=180></e-column>
                    <e-column field='startDate' headerText='Start Date' textAlign='Right' format='yMd' width=120></e-column>
                    <e-column field='duration' headerText='Duration' textAlign='Right' width=110></e-column>
        </e-columns>
                </ejs-treegrid>`
})
export class AppComponent implements OnInit {

    public data: Object[];

    ngOnInit(): void {
        this.data = sampleData;
    }

    @ViewChild('treegrid')
    public treeGridObj: TreeGridComponent;
    @ViewChild('numerictext')
    public numeric: NumericTextBoxComponent;
    onChange(): void {
        this.treeGridObj.selectRow(parseInt(this.numeric.getText(), 10));
    }

    rowSelected(args: RowSelectEventArgs) {
        let rowHeight: number = this.treeGridObj.getRows()[this.treeGridObj.getSelectedRowIndexes()[0]].scrollHeight;
        this.treeGridObj.getContent().children[0].scrollTop = rowHeight * this.treeGridObj.getSelectedRowIndexes()[0];
    }
}
import { NgModule,ViewChild } from '@angular/core';
import { BrowserModule } from '@angular/platform-browser';
import { TreeGridModule } from '@syncfusion/ej2-angular-treegrid';
import { AppComponent } from './app.component';
import {ButtonModule} from '@syncfusion/ej2-angular-buttons';
import { NumericTextBoxModule } from '@syncfusion/ej2-angular-inputs';

/**
 * Module
 */
@NgModule({
    imports: [
        BrowserModule,
        TreeGridModule,
        ButtonModule,
        NumericTextBoxModule
    ],
    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);

Hide the scrollbar when the content is not overflown

Hide the scrollbar of the tree grid content by using the hideScroll method when the content doesn’t overflow its parent element.

In the following sample, the hideScroll method is invoked inside the dataBound event.

import { Component, OnInit, ViewChild } from '@angular/core';
import { sampleData } from './datasource';
import { TreeGridComponent } from '@syncfusion/ej2-angular-treegrid';

@Component({
    selector: 'app-container',
    template: `<ejs-treegrid #treegrid [dataSource]='data' height='315' [treeColumnIndex]='1'  childMapping='subtasks' (dataBound)='dataBound($event)'>
                    <e-columns>
                        <e-column field='taskID' headerText='Task ID' textAlign='Right' width=90></e-column>
                        <e-column field='taskName' headerText='Task Name' textAlign='Left' width=180></e-column>
                        <e-column field='startDate' headerText='Start Date' textAlign='Right' format='yMd' width=120></e-column>
                        <e-column field='duration' headerText='Duration' textAlign='Right' width=110></e-column>
                    </e-columns>
                </ejs-treegrid>`
})
export class AppComponent implements OnInit {

    public data: object[];
    @ViewChild('treegrid')
    public treegrid: TreeGridComponent;

    ngOnInit(): void {
        this.data = sampleData.slice(0, 1);
    }
    dataBound(): void {
        this.treegrid.grid.hideScroll();
    }
}
import { NgModule,ViewChild } from '@angular/core';
import { BrowserModule } from '@angular/platform-browser';
import { TreeGridModule } from '@syncfusion/ej2-angular-treegrid';
import { AppComponent } from './app.component';
import {ButtonModule} from '@syncfusion/ej2-angular-buttons';
import { NumericTextBoxModule } from '@syncfusion/ej2-angular-inputs';

/**
 * Module
 */
@NgModule({
    imports: [
        BrowserModule,
        TreeGridModule,
        ButtonModule,
        NumericTextBoxModule
    ],
    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);