Headers in Angular TreeGrid component

19 Sep 202424 minutes to read

Header text

By default, the header text of a column in Tree Grid is displayed from the column’s field value. However, you can easily override the default header title and provide a custom header text for the column using the headerText property.

To enable the headerText property, you simply need to define it in the e-column element. The following example demonstrates how to enable header text for a tree grid column.

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

@Component({
    imports: [TreeGridModule,],
    providers: [PageService, SortService, FilterService],
    standalone: true,
    selector: 'app-container',
    template: `<ejs-treegrid #treegrid [dataSource]='data' height='285' [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=90></e-column>
                    <e-column field='duration' headerText='Duration' textAlign='Right' width=80></e-column>
                    <e-column field='progress' headerText='Progress' textAlign='Right' width=120></e-column>
                 </e-columns>
               </ejs-treegrid>`,

})
export class AppComponent implements OnInit {

    public data?: Object[];

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

}
import { bootstrapApplication } from '@angular/platform-browser';
import { AppComponent } from './app.component';
import 'zone.js';
bootstrapApplication(AppComponent).catch((err) => console.error(err));

  • The headerText property is optional, and if it is not defined, then the corresponding column’s field value is set as header text for that column.
  • You can also use the headerTemplate property to apply custom HTML content to the header cell.

Header template

You can customize the header element by using the headerTemplate property. With this property, you can render custom HTML elements or Angular components to the header element.

In this demo, the custom element is rendered for both taskName and duration column headers.

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

@Component({
    imports: [TreeGridModule,],
    providers: [PageService, SortService, FilterService],
    standalone: true,
    selector: 'app-container',
    template: `<ejs-treegrid [dataSource]='data' childMapping='subtasks' height='250' >
        <e-columns>
            <e-column field='taskName' width='170'><ng-template #headerTemplate>      <div>
        <div>
            <img src="__Task name.png" width="20" height="20" class="e-image" />  Task Name
        </div>
    </div></ng-template> </e-column>
            <e-column field='startDate'  width='130' format="yMd" textAlign='Right'></e-column>
            <e-column field='duration' headerText='Duration' width='80' textAlign='Right'> <ng-template #headerTemplate>    <div>
        <div>
            <img src="__Duration.png" width="20" height="20" class="e-image" />  Duration
        </div>
    </div></ng-template></e-column>
    <e-column field='progress' width='90' textAlign='Right'></e-column>
        </e-columns>
                </ejs-treegrid>`
})
export class AppComponent implements OnInit {

    public data?: Object[];

    ngOnInit(): void {
        this.data = headerData;
    }
}
import { bootstrapApplication } from '@angular/platform-browser';
import { AppComponent } from './app.component';
import 'zone.js';
bootstrapApplication(AppComponent).catch((err) => console.error(err));

  • The headerTemplate property is only applicable to Tree Grid columns that have a header element.
  • You can use any HTML or Angular component in the header template to add additional functionality to the header element.

Stacked header

In Tree Grid, you can group multiple levels of column headers by stacking the tree grid columns. This feature allows you to organize the tree grid columns in a more structured and understandable way. This can be achieved by setting the column->columns property. Within this property, you can define an array of column objects to group together as sub-headers under a main header. You can define the headerText property of each sub-header column to set the text for that sub-header.

You can customize the appearance of the stacked header elements by using the headerTemplate property. This property accepts an ng-template reference, which allows you to define custom HTML elements or Angular components to the header element. Here’s an example of how to use stacked headers with a custom headerTemplate in Syncfusion Tree Grid.

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

@Component({
    imports: [TreeGridModule,],
    providers: [PageService, SortService, FilterService],
    standalone: true,
    selector: 'app-container',
    template: `<ejs-treegrid #treegrid [dataSource]='data' childMapping='subtasks' height='260'  [treeColumnIndex]='1' >
            <e-columns>
                <e-column headerText='Order Details'  [columns]='orderColumns'><ng-template #headerTemplate let-data > <div><a href="#">OrderColumns</a></div></ng-template> </e-column>
                <e-column headerText='Shipment Details' [columns]='shipColumns'></e-column>
                <e-column headerText='Price Details' [columns]='priceColumns'></e-column>
            </e-columns>
        </ejs-treegrid>`,
})
export class AppComponent implements OnInit {

    public data?: Object[];
    public orderColumns?: Object[];
    public shipColumns?: Object[];
    public priceColumns?: Object[];

    ngOnInit(): void {
        this.data = stackedData;
        this.orderColumns = [
            { field: 'orderID', headerText: 'Order ID', textAlign: 'Right', width: 90 },
            { field: 'orderName', headerText: 'Order Name', textAlign: 'Left', width: 180 },
            { field: 'orderDate', headerText: 'Order Date', textAlign: 'Right', width: 120, format: 'yMd' }
        ];
        this.shipColumns = [
            { field: 'shipMentCategory', headerText: 'Shipment Category', textAlign: 'Left', width: 150 },
            { field: 'shippedDate', headerText: 'Shipped Date', textAlign: 'Right', width: 120, format: 'yMd' },
            { field: 'units', headerText: 'Units', textAlign: 'Right', width: 90 }
        ];
        this.priceColumns = [
            { field: 'unitPrice', headerText: 'Price per unit', format: 'c2', type: 'number', width: 120, textAlign: 'Right' },
            { field: 'price', headerText: 'Total Price', width: 110, format: 'c2', type: 'number', textAlign: 'Right' }
        ];
    }
}
import { bootstrapApplication } from '@angular/platform-browser';
import { AppComponent } from './app.component';
import 'zone.js';
bootstrapApplication(AppComponent).catch((err) => console.error(err));

Align the text of header text

You can horizontally align the text in column headers of the TreeGrid component using the headerTextAlign property. By default, the text is aligned to the left, but you can change the alignment by setting the value of the headerTextAlign property to one of the following options:

  • Left: Aligns the text to the left (default).
  • Center: Aligns the text to the center.
  • Right: Aligns the text to the right.
  • Justify: Header text is justified.

Here is an example of using the headerTextAlign property to align the text of a tree grid column header:

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

@Component({
    imports: [TreeGridModule, DropDownListAllModule],
    providers: [PageService, SortService, FilterService],
    standalone: true,
    selector: 'app-container',
    template: `<div style="display: flex">
              <label style="padding: 30px 17px 0 0;">Align the text of header text :</label>
              <ejs-dropdownlist  style="padding: 26px 0 0 0" index="0" width="100" [dataSource]="alignmentData" (change)="changeAlignment($event)">
              </ejs-dropdownlist>
              </div>
            <ejs-treegrid #treegrid [dataSource]='data' height='250' [treeColumnIndex]='1' childMapping='subtasks'>
                <e-columns>
                    <e-column field='taskID' headerText='Task ID' width=90></e-column>
                    <e-column field='taskName' headerText='Task Name' width=180></e-column>
                    <e-column field='startDate' headerText='Start Date' format='yMd' width=90></e-column>
                    <e-column field='approved' headerText='Approved' width='100'> </e-column>
                    <e-column field='duration' headerText='Duration' width=100></e-column>
                </e-columns>
            </ejs-treegrid>`
})
export class AppComponent implements OnInit {

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

    public alignmentData: Object[] = [
        { text: 'Left', value: 'Left' },
        { text: 'Right', value: 'Right' },
        { text: 'Center', value: 'Center' },
        { text: 'Justify', value: 'Justify' }
    ];

    public changeAlignment(args: ChangeEventArgs): void {
        (this.treegrid as TreeGridComponent).grid.columns.forEach((col: any) => {
            (col as Column).headerTextAlign = args.value as any;
        });
        (this.treegrid as TreeGridComponent).refreshHeader();
    }
    ngOnInit(): void {
        this.data = sampleData;
    }
}
import { bootstrapApplication } from '@angular/platform-browser';
import { AppComponent } from './app.component';
import 'zone.js';
bootstrapApplication(AppComponent).catch((err) => console.error(err));

  • The headerTextAlign property only changes the alignment of the text in the column header, and not the content of the column. If you want to align both the column header and content, you can use the textAlign property.
  • You can also use the headerTextAlign property with the stacked header feature in Syncfusion Tree Grid. The property will align the header text in the sub-headers as well.

Autowrap the header text

The autowrap allows the cell content of the tree grid to wrap to the next line when it exceeds the boundary of the specified cell width. The cell content wrapping works based on the position of white space between words. To support the Autowrap functionality in Syncfusion Tree Grid, you should set the appropriate width for the columns. The column width defines the maximum width of a column and helps to wrap the content automatically.

To enable autowrap, set the allowTextWrap property to true. You can also configure the auto wrap mode by setting the textWrapSettings.wrapMode property.

Tree Grid provides the below three options for configuring:

  • Both: This is the default value for wrapMode. With this option, both the tree grid header text and content is wrapped.
  • Header: With this option, only the tree grid header text is wrapped.
  • Content: With this option, only the tree grid content is wrapped.
  • If a column width is not specified, then the Autowrap of columns will be adjusted with respect to the tree grid’s width.
  • If a column’s header text contains no white space, the text may not be wrapped.
  • If the content of a cell contains HTML tags, the Autowrap functionality may not work as expected. In such cases, you can use the headerTemplate and template properties of the column to customize the appearance of the header and cell content.

In the example below, the textWrapSettings.wrapMode property is set to Header; only the tree grid header text wraps to the next line.

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 { ButtonModule } from '@syncfusion/ej2-angular-buttons'
import { TextWrapSettingsModel } from '@syncfusion/ej2-angular-grids';
import { DropDownListModule } from '@syncfusion/ej2-angular-dropdowns';
import { Component, OnInit } from '@angular/core';
import { sampleData } from './datasource';
import { TreeGridComponent, WrapMode } from '@syncfusion/ej2-angular-treegrid';
import { ChangeEventArgs } from '@syncfusion/ej2-dropdowns';

@Component({
    imports: [TreeGridModule, ButtonModule, DropDownListModule],
    providers: [PageService, SortService, FilterService],
    standalone: true,
    selector: 'app-container',
    template: `<div style="display: flex">
               <label style="padding: 30px 17px 0 0" >Autowrap for header column :</label>
               <ejs-dropdownlist style="padding: 26px 0 0 0" index="0" width="100" [dataSource]=" dropdownData" (change)="valueChange($event)">
               </ejs-dropdownlist>
              </div>
    
              <ejs-treegrid #treegrid [dataSource]='data' height='250' [treeColumnIndex]='1' childMapping='subtasks' allowPaging='true' allowTextWrap='true' 
               [textWrapSettings]='wrapSettings'>
                 <e-columns>
                    <e-column field='taskID' headerText='Task ID' [allowSorting]="false" textAlign='Right' width=120></e-column>
                    <e-column field='taskName' headerText='Task Name' textAlign='Left' width=80></e-column>
                    <e-column field='startDate' headerText='Start Date' [allowFiltering]="false" textAlign='Right' format='yMd' width=120></e-column>
                    <e-column field='duration' headerText='Duration' textAlign='Right' width=120></e-column>
                    <e-column field='progress' headerText='Progress' textAlign='Right' width=120></e-column>
                  </e-columns>
                </ejs-treegrid>`,
})
export class AppComponent implements OnInit {

    public data?: Object[];
    @ViewChild('treegrid')
    public treegrid?: TreeGridComponent;
    public wrapSettings: TextWrapSettingsModel = { wrapMode: 'Header' };
    public dropdownData: Object[] = [
        { text: 'Header', value: 'Header' },
        { text: 'Both', value: 'Both' },
    ];

    valueChange(args: ChangeEventArgs): void {
        (this.treegrid as TreeGridComponent).textWrapSettings.wrapMode = (args.value as WrapMode);
    }
    ngOnInit(): void {
        this.data = sampleData;
    }
}
import { bootstrapApplication } from '@angular/platform-browser';
import { AppComponent } from './app.component';
import 'zone.js';
bootstrapApplication(AppComponent).catch((err) => console.error(err));

Change the height of header

Changing the height of the header can be useful in cases where the default height is not sufficient to display the header content cell. For example, if you have a header with a lot of text or if you want to add an image to the header, you may need to increase the height of the header to accommodate the content. This can be easily achieved by changing the height of the header using CSS or by dynamically adjusting the height in JavaScript.

Using css

You can use CSS to override the default height of the .e-treegrid .e-headercell class to change the height of the header. Here is an example code snippet:

.e-treegrid .e-headercell {
  height: 130px;
}

Using methods

To change the height of the header dynamically, you can use the getHeaderContent method to get the header content element of the tree grid. Then, you can use the querySelectorAll method to get all the header cell elements with the class e-headercell. Finally, you can loop through each header cell element and set its style property to adjust the height.

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

@Component({
    imports: [TreeGridModule, ButtonModule],
    providers: [PageService, SortService, FilterService],
    standalone: true,
    selector: 'app-container',
    template: `<div >
                <button ejs-button id="small" cssClass="e-small" (click)="changeHeaderHeight($event)">Change height 20px</button>
                <button ejs-button id="medium" cssClass="e-small" (click)="changeHeaderHeight($event)">Default height 42px</button>
                <button ejs-button  id="big" cssClass="e-small" (click)="changeHeaderHeight($event)">Change height 60px</button>
              </div>

              <ejs-treegrid #treegrid [dataSource]='data' height='250' [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=90></e-column>
                    <e-column field='duration' headerText='Duration' textAlign='Right' width=80></e-column>
                    <e-column field='progress' headerText='Progress' textAlign='Right' width=120></e-column>
                  </e-columns>
              </ejs-treegrid>`
})
export class AppComponent implements OnInit {

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

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

    }
    changeHeaderHeight(event: MouseEvent): void {
        const heightMap: { [key: string]: string } = {
            small: '20px',
            medium: '42px',
            big: '60px'
        }; const headerCells = (this.treegrid as TreeGridComponent).getHeaderContent().querySelectorAll('.e-headercell');
        headerCells.forEach((headerCell: Element) => {
            (headerCell as HTMLElement).style.height = (heightMap)[
                (event.target as HTMLButtonElement).id
            ];
        });
    }
}
import { bootstrapApplication } from '@angular/platform-browser';
import { AppComponent } from './app.component';
import 'zone.js';
bootstrapApplication(AppComponent).catch((err) => console.error(err));

  • You can also use the getHeaderTable method to get the table element of the header, and then adjust the height.
  • You cannot change the height of row below the default height of 42px using the e-columnheader class.

Change header text dynamically

The Syncfusion TreeGrid component provides a way to modify the header text of a corresponding column in real-time based on an event. This feature can be useful in various scenarios, such as displaying a custom header text for a specific column or updating the header text dynamically based on input. By allowing for dynamic changes to the header text, the tree grid provides a more flexible and customizable experience.

Using Event

To modify the header text of a corresponding column dynamically, you can use the headerCellInfo event provided by the Syncfusion Tree Grid. This event is triggered for each header cell element rendered in the tree grid.

When the headerCellInfo event is triggered, it provides a HeaderCellInfoEventArgs object as a parameter. This object contains the following properties:

  • cell: Defines the header cell that is being modified.
  • node: Defines the DOM element of the header cell that is being modified.

You can use these properties to access and modify the header text of the corresponding column. Once the header text is modified, you can refresh the tree grid to reflect the changes by calling the refreshHeader method of the Tree Grid.

Using method

The TreeGrid component provides several methods that allow you to change the column header text dynamically. Here are some of the methods you can use:

  1. getColumnByField: This method takes a field name as a parameter and returns the entire column object that corresponds to that field name, including properties such as headerText, width, and alignment. You can use this method to modify any aspect of the column.

  2. getColumnHeaderByField: Retrieves the header element of a column based on its field name. You can modify the textContent property of the header element to change the header text. This method does not return a reference to the column object itself, only to the header element.

  3. getColumnIndexByField: Retrieves the index of a column based on its field name. You can then use the getColumnByIndex method to retrieve the column object and modify its headerText property to change the header text.

  4. getColumnByUid: Retrieves the column object based on its unique identifier (UID). You can modify the headerText property of the column object to change the header text.

  5. getColumnHeaderByIndex: Retrieves the header element of a column based on its zero-based index. You can modify the textContent property of the header element to change the header text. This method does not return a reference to the column object itself, only to the header element.

  6. getColumnIndexByUid: Retrieves the index of a column based on its unique identifier (UID). You can then use the getColumnByIndex method to retrieve the column object and modify its headerText property to change the header text.

  7. getColumnHeaderByUid: Retrieves the header element of a column based on its unique identifier (UID). You can modify the textContent property of the header element to change the header text. This method does not return a reference to the column object itself, only to the header element.If you only have an ng-template for the column header, and the column itself is not defined with a field, then you can use the getColumnHeaderByUid method to get a reference to the header element and modify its text content to change the header text.

  • When you change the header text dynamically, make sure to refresh the tree grid to reflect the changes by calling the refreshHeader method.
  • The UID is automatically generated by the TreeGrid component and may change whenever the tree grid is refreshed or updated.

Here is an example of how to change the header text of a column using the getColumnByField method:

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 { ButtonModule } from '@syncfusion/ej2-angular-buttons'
import { DropDownListAllModule } from '@syncfusion/ej2-angular-dropdowns'
import { TextBoxModule } from '@syncfusion/ej2-angular-inputs'
import { Component, OnInit } from '@angular/core';
import { sampleData } from './datasource';
import { DropDownListComponent } from '@syncfusion/ej2-angular-dropdowns';
import { TreeGridComponent } from '@syncfusion/ej2-angular-treegrid';
import { TextBoxComponent } from '@syncfusion/ej2-angular-inputs';

@Component({
    imports: [TreeGridModule, ButtonModule, DropDownListAllModule, TextBoxModule],
    providers: [PageService, SortService, FilterService],
    standalone: true,
    selector: 'app-container',
    template: `<div style="display: flex">
               <label style="padding: 30px 20px 0 0" > Select column name  :</label>
               <ejs-dropdownlist  #dropdown style="padding: 26px 0 0 0" index='0' width="220" [dataSource]="columns"  [fields]="field"></ejs-dropdownlist>
               </div>
   
               <div>
                  <label style="padding: 30px 17px 0 0" >Enter new header text :</label>
                  <ejs-textbox #textbox required placeholder="Enter new header text" width="220">
                   </ejs-textbox>
                </div>

                <div>
                    <label style="padding: 30px 17px 0 0" >Click the change button :</label>
                    <button ejs-button id="buttons" (click)="ChangeHeaderText()">Change</button>
                </div>

               <div style="padding: 20px 17px 0 0">
                  <ejs-treegrid #treegrid [dataSource]='data' height='250' [treeColumnIndex]='1' childMapping='subtasks'  [allowFiltering]="true" [allowSorting]="true">
                     <e-columns>
                        <e-column field='taskID' headerText='Task ID' [allowSorting]="false" textAlign='Right' width=120></e-column>
                        <e-column field='taskName' headerText='Task Name' textAlign='Left' width=180></e-column>
                        <e-column field='startDate' headerText='Start Date' [allowFiltering]="false" textAlign='Right' format='yMd' width=120></e-column>
                        <e-column field='duration' headerText='Duration' textAlign='Right' width=120></e-column>
                        <e-column field='progress' headerText='Progress' textAlign='Right' width=120></e-column>
                      </e-columns>
                  </ejs-treegrid> 
                </div>`,
})
export class AppComponent implements OnInit {

    public data?: Object[];
    public columns: Object[] = [
        { text: 'Task ID', value: 'taskID' },
        { text: 'Task Name', value: 'taskName' },
        { text: 'Start Date', value: 'startDate' },
        { text: 'Duration', value: 'duration' },
        { text: 'Progress', value: 'progress' }
    ];
    public field?: Object = { text: 'text', value: 'value' };
    @ViewChild('dropdown') public dropdown?: DropDownListComponent;
    @ViewChild('textbox') public textbox?: TextBoxComponent;
    @ViewChild('treegrid')
    public treegrid?: TreeGridComponent;

    public ChangeHeaderText(): void {
        if ((this.textbox as TextBoxComponent).element.value.trim() !== '') {
            const column = (this.treegrid as TreeGridComponent).grid.getColumnByField(
                (((this.dropdown as DropDownListComponent).value as string))
            );
            column.headerText = (this.textbox as TextBoxComponent).element.value;
            (this.treegrid as TreeGridComponent).refreshHeader();
        }
    }
    ngOnInit(): void {
        this.data = sampleData;
    }
}
import { bootstrapApplication } from '@angular/platform-browser';
import { AppComponent } from './app.component';
import 'zone.js';
bootstrapApplication(AppComponent).catch((err) => console.error(err));

Changing the header text of all columns

If you want to change the header text of all columns in the tree grid, you can loop through the Columns collection of the tree grid and set the headerText property for each column. Here is an example:

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

@Component({
    imports: [TreeGridModule, ButtonModule],
    providers: [PageService, SortService, FilterService],
    standalone: true,
    selector: 'app-container',
    template: `<div>
                    <label style="padding: 30px 17px 0 0" >Click the change button :</label>
                    <button ejs-button id="buttons" (click)="ChangeHeaderText()">Change</button>
                </div>

               <div style="padding: 20px 17px 0 0">
                  <ejs-treegrid #treegrid [dataSource]='data' height='250' [treeColumnIndex]='1' childMapping='subtasks'  [allowFiltering]="true" [allowSorting]="true">
                     <e-columns>
                        <e-column field='taskID' headerText='Task ID' [allowSorting]="false" textAlign='Right' width=120></e-column>
                        <e-column field='taskName' headerText='Task Name' textAlign='Left' width=180></e-column>
                        <e-column field='startDate' headerText='Start Date' [allowFiltering]="false" textAlign='Right' format='yMd' width=120></e-column>
                        <e-column field='duration' headerText='Duration' textAlign='Right' width=120></e-column>
                        <e-column field='progress' headerText='Progress' textAlign='Right' width=120></e-column>
                      </e-columns>
                  </ejs-treegrid> 
                </div>`,
})
export class AppComponent implements OnInit {

    public data?: Object[];
    public headerTextMap: { [key: string]: string } = {
        'taskID': 'Task ID',
        'taskName': 'Task Name',
        'startDate': 'Start Date',
        'duration': 'Duration',
        'progress': 'Progress'
    };

    @ViewChild('treegrid')
    public treegrid?: TreeGridComponent;

    public ChangeHeaderText(): void {
        this.treegrid?.columns.forEach((column: any) => {
            column.headerText = this.headerTextMap[column.field as string];
        });
        this.treegrid?.refreshHeader();
    }

    ngOnInit(): void {
        this.data = sampleData;
    }
}
import { bootstrapApplication } from '@angular/platform-browser';
import { AppComponent } from './app.component';
import 'zone.js';
bootstrapApplication(AppComponent).catch((err) => console.error(err));

Change the orientation of header text

By default, the text in the column headers of the Syncfusion Tree Grid control is oriented horizontally. However, in some cases, you may want to change the orientation of the header text to vertical, diagonal, or at a custom angle. This can be achieved by adding a custom CSS class to the column header cell using the customAttributes property of the tree grid columns.

Follow the below steps to change the orientation of the header text in Tree Grid:

Step 1: Create a CSS class with orientation style for tree grid header cell

To rotate the header text, you can create a CSS class with the transform property that rotates the header text 90 degrees. This class will be added to the header cell using the customAttributes property.

.orientationcss .e-headercelldiv {
    transform: rotate(90deg);
}

Step 2: Add the custom CSS class to the tree grid column

Once you have created the CSS class, you can add it to the particular column by using the customAttributes property. This property allows you to add any custom attribute to the tree grid column.

For example, to add the orientationcss class to the EndDate column, you can use the following code:

<e-column field='EndDate' headerText='End Date' width='90' format="yMd" textAlign='Center' [customAttributes]='customAttributes' ></e-column>

Step 3: Resize the header cell height

After adding the custom CSS class to a column, you need to resize the header cell height so that the rotated header text is fully visible. You can achieve this by using the ‘created’ event of the tree grid, as shown in the following code:

setHeaderHeight(args) {
    let textWidth: number = document.querySelector('.orientationcss > div').scrollWidth;//Obtain the width of the headerText content.
    let headerCell: NodeList = document.querySelectorAll('.e-headercell');
    for(let i: number = 0; i < headerCell.length; i++) {
        (<HTMLElement>headerCell.item(i)).style.height = textWidth + 'px'; //Assign the obtained textWidth as the height of the headerCell.
    }
}
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 { Component, OnInit, ViewEncapsulation } from '@angular/core';
import { projectData } from './datasource';
import { TreeGridComponent } from '@syncfusion/ej2-angular-treegrid';

@Component({
    imports: [TreeGridModule],
    providers: [PageService, SortService, FilterService],
    standalone: true,
    selector: 'app-container',
    styleUrls: ['./app.component.css'],
    encapsulation: ViewEncapsulation.None,
    template: `<ejs-treegrid #treegrid [dataSource]='data' idMapping='TaskID' parentIdMapping='parentID' [height]='194' [treeColumnIndex]='1' (created)='setHeaderHeight($event)'  >
                     <e-columns>
                        <e-column field='TaskID' headerText='Task ID' width='70' textAlign='Right'></e-column>
                        <e-column field='TaskName' headerText='Task Name' width='100' ></e-column>
                        <e-column field='StartDate' headerText='Start Date' width='90' format="yMd" textAlign='Right' ></e-column>
                        <e-column field='EndDate' headerText='End Date' width='90' format="yMd" textAlign='Center' [customAttributes]='customAttributes' ></e-column>
                        <e-column field='Duration' headerText='Duration' width='90' textAlign='Right' ></e-column>
                        <e-column field='Progress' headerText='Progress' width='90' textAlign='Right' ></e-column>
                    </e-columns>
                </ejs-treegrid>`,
})
export class AppComponent implements OnInit {

    public data: Object[] = [];
    public customAttributes?: Object;

    ngOnInit(): void {
        this.data = projectData;
        this.customAttributes = { class: 'orientationcss' };
    }
    setHeaderHeight(args: any) {
        const textWidth: number = (document.querySelector('.orientationcss > div') as Element).scrollWidth as number; // Obtain the width of the headerText content.
        const headerCell: NodeList = document.querySelectorAll('.e-headercell');
        for (let i = 0; i < headerCell.length; i++) {
            // Assign the obtained textWidth as the height of the headerCell.
            (headerCell.item(i) as HTMLElement).style.height = textWidth + 'px';
        }
    }
}
import { bootstrapApplication } from '@angular/platform-browser';
import { AppComponent } from './app.component';
import 'zone.js';
bootstrapApplication(AppComponent).catch((err) => console.error(err));

Translate header text using ngx-translate

The ngx-translate library provides internationalization (i18n) and localization (l10n) support for Angular applications. With ngx-translate, you can easily translate your Angular application into multiple languages.

In the context of the Syncfusion Angular TreeGrid component, you can use ngx-translate to translate the header text of the Tree Grid’s columns. There are two ways to achieve this: through header text and through header template.

Through header text

To translate the header text of the Tree Grid’s columns using ngx-translate through header text, you can use the translate pipe for the headerText property.

Step 1: Create and Configure the TranslateService

import { Component, ViewChild } from '@angular/core';
import { TranslateService } from '@ngx-translate/core';
import { TreeGridComponent } from '@syncfusion/ej2-angular-treegrid';
@Component({
  selector: 'app-root',
  templateUrl: './app.component.html',
  styleUrls: ['./app.component.css'],
})
export class AppComponent {
  constructor(public translate: TranslateService) {
  }

  @ViewChild('treegrid', { static: true })
  public treegrid!: TreeGridComponent;
  public flag: boolean = true;
  public data: Object[] = [];

  changeLanguage(lang: string) {
    this.translate.use(lang);

    setTimeout(() => {
      this.treegrid.refreshHeader();
    }, 500);
  }

  ngOnInit(): void {
    this.data = [
      {
        OrderID: 10248,
        CustomerID: 'VINET',
        lineId: 5,
        start: 'Reims',
        destination: 'France',
        subtasks [
         {
           OrderID: 10249,
           CustomerID: 'TOMSP',
           lineId: 6,
           start: 'Münster',
           destination: 'Germany',
          },
         {
           OrderID: 10250,
           CustomerID: 'HANAR',
           lineId: 2,
           start: 'Rio de Janeiro',
           destination: 'Brazil',
         },
        ]
      }
    ];
  }
}

Step 2: Import the TranslateModule and TranslateLoader in your app.module.ts file. You also need to import the HttpClientModule to enable HTTP requests for loading translation files.

import { NgModule } from '@angular/core';
import { BrowserModule } from '@angular/platform-browser';
import { HttpClient, HttpClientModule } from '@angular/common/http';
import { TranslateModule, TranslateLoader } from '@ngx-translate/core';
import { TranslateHttpLoader } from '@ngx-translate/http-loader';
import { AppComponent } from './app.component';
import { TreeGridAllModule } from '@syncfusion/ej2-angular-treegrid';
import { CommonModule } from '@angular/common';
import { ButtonModule } from '@syncfusion/ej2-angular-buttons';

export function createTranslateLoader(http: HttpClient) {
  return new TranslateHttpLoader(http, './assets/i18n/', '.json');
}

@NgModule({
  imports: [
    BrowserModule,
    HttpClientModule,
    TranslateModule.forRoot({
      loader: {
        provide: TranslateLoader,
        useFactory: createTranslateLoader,
        deps: [HttpClient],
      },
      defaultLanguage: '',
    }),
    CommonModule,
    TreeGridAllModule,
    BrowserModule,
    ButtonModule
  ],
  declarations: [AppComponent],
  bootstrap: [AppComponent],
})
export class AppModule {}

In the above code, we import the required modules and define a function called HttpLoaderFactory that returns an instance of TranslateHttpLoader, which is used to load translation files.

Step 3: Use the translate pipe in your HTML code to translate the headerText of the column.

<h1> Ngx translate pipe for header text in Angular TreeGrid component</h1>
<h1></h1>
<div class="container-fluid py-3">
  <div class="btn-group btn-group-sm py-5">
    <button  ejs-button type="button" class="btn btn-sm btn-info"
     (click)="changeLanguage('en')">en</button>
    <button  ejs-button type="button" class="btn btn-sm btn-success"
    (click)="changeLanguage('de')">de</button>
    <button  ejs-button ejs-button type="button" ejs-button class="btn btn-sm btn-warning"
    (click)="changeLanguage('es-ES')">es</button>
  </div>
</div>
<div style="padding:20px 0px 0px 0px">
  <ejs-treegrid #treegrid [dataSource]="data" childMapping="subtasks" treeColumnIndex='1' height="350">
    <e-columns>
      <e-column field="OrderID" headerText="Order ID" width="120" textAlign="Right"></e-column>
      <e-column field="lineId" headerText="{{ 'Line' | translate }}" width="120" textAlign="Right">
      </e-column>
      <e-column field="start" headerText="{{ 'Start' | translate }}" width="140">
      </e-column>
      <e-column field="destination" headerText="{{ 'Destination' | translate }}" width="170">
      </e-column>
    </e-columns>
  </ejs-treegrid>
<div>

Step 4: Then add the json file with the translation text in the required languages,

en.json { 

    "Line": "Line",
    "Start": "Start",
    "Destination": "Destination"

}
de.json { 
 "changeLanguage": "Ändere Sprache",
    "Line": "Linie",
    "Start": "Startpunkt",
    "Destination": "Zielpunkt"
}
es-ES.json {
    "changeLanguage": "cambiar idioma",
    "Line": "Línea",
    "Start": "Comenzar",
    "Destination": "Destino"
  }

Through header template

To translate the header text of the Tree Grid’s columns using ngx-translate through header template, you can use the translate pipe in the header templates of the TreeGrid component.

Here are the steps to use ngx-translate pipe for Tree Grid’s header template in Angular TreeGrid component:

Step 1: Create and Configure the TranslateService

import { Component, ViewChild } from '@angular/core';
import { TranslateService } from '@ngx-translate/core';
import { TreeGridComponent } from '@syncfusion/ej2-angular-treegrid';
@Component({
  selector: 'app-root',
  templateUrl: './app.component.html',
  styleUrls: ['./app.component.css'],
})
export class AppComponent {
  constructor(public translate: TranslateService) {
  }

  @ViewChild('treegrid', { static: true })
  public treegrid!: TreeGridComponent;
  public flag: boolean = true;
  public data: Object[] = [];

  changeLanguage(lang: string) {
    this.translate.use(lang);
  }

  ngOnInit(): void {
    this.data = [
      {
        OrderID: 10248,
        CustomerID: 'VINET',
        lineId: 5,
        start: 'Reims',
        destination: 'France',
        subtasks [
         {
           OrderID: 10249,
           CustomerID: 'TOMSP',
           lineId: 6,
           start: 'Münster',
           destination: 'Germany',
          },
         {
           OrderID: 10250,
           CustomerID: 'HANAR',
           lineId: 2,
           start: 'Rio de Janeiro',
           destination: 'Brazil',
         },
        ]
      }
    ];
  }
}

Step 2: Import the required modules in app.module.ts file along with translate loader function,

import { NgModule } from '@angular/core';
import { BrowserModule } from '@angular/platform-browser';
import { HttpClient, HttpClientModule } from '@angular/common/http';
import { TranslateModule, TranslateLoader } from '@ngx-translate/core';
import { TranslateHttpLoader } from '@ngx-translate/http-loader';
import { AppComponent } from './app.component';
import { TreeGridAllModule } from '@syncfusion/ej2-angular-treegrid';
import { CommonModule } from '@angular/common';
import { ButtonModule } from '@syncfusion/ej2-angular-buttons';

export function createTranslateLoader(http: HttpClient) {
  return new TranslateHttpLoader(http, './assets/i18n/', '.json');
}

@NgModule({
  imports: [
    BrowserModule,
    HttpClientModule,
    TranslateModule.forRoot({
      loader: {
        provide: TranslateLoader,
        useFactory: createTranslateLoader,
        deps: [HttpClient],
      },
      defaultLanguage: 'en-US',
    }),
    CommonModule,
    TreeGridAllModule,
    BrowserModule,
    ButtonModule
  ],
  declarations: [AppComponent],
  bootstrap: [AppComponent],
})
export class AppModule {}

Step 3: Use the ngx-translate pipe in your Angular TreeGrid component header templates to translate the headers dynamically.

<h1> Ngx translate pipe for header template in Angular TreeGrid component</h1>
<h1></h1><div class="container-fluid py-3">
  <div class="btn-group btn-group-sm py-5">
    <button ejs-button type="button" class="btn btn-sm btn-info" 
    (click)="changeLanguage('en-US')"> en-US</button>
    <button ejs-button type="button" class="btn btn-sm btn-success"
    (click)="changeLanguage('de-DE')"> de-DE</button>
  </div>
</div>
<div style="padding:20px 0px 0px 0px">
  <ejs-treegrid [dataSource]="data" childMapping='subtasks' treeColumnIndex=1 height="350">
    <e-columns>
      <e-column
        field="OrderID"
        headerText="Order ID"
        width="120"
        textAlign="Right"
      ></e-column>
      <e-column field="lineId" width="120" textAlign="Right"
        ><ng-template #headerTemplate let-data>
          <div>
            {{ 'Line' | translate }}
          </div>
        </ng-template></e-column
      >
      <e-column field="start" width="140"
        ><ng-template #headerTemplate let-data>
          <div>
            {{ 'Start' | translate }}
          </div>
        </ng-template></e-column
      >
      <e-column field="destination" width="170"
        ><ng-template #headerTemplate let-data>
          <div>
            {{ 'Destination' | translate }}
          </div>
        </ng-template></e-column>
    </e-columns>
  </ejs-treegrid>
</div>

Step 4: Then add the json file with the translation text in the required languages,

en.json { 

    "Line": "Line",
    "Start": "Start",
    "Destination": "Destination"
}
de.json { 
 "changeLanguage": "Ändere Sprache",
    "Line": "Linie",
    "Start": "Startpunkt",
    "Destination": "Zielpunkt"
}

Custom tooltip for header

Custom tooltips for headers provide additional information when hovering over a column header in the Syncfusion Tree Grid. This can be useful in situations where there is not enough space to display all of the information related to a column, or when there is additional context that may be helpful.

To enable custom tooltips for headers, you can use the beforeRender event of the Tooltip component. This event is triggered for each header cell before it is rendered, allowing you to add a custom tooltip to the header cell using tooltip component.

Here’s an example of how to use the beforeRender event to add a custom tooltip to a header cell:

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 { Component, OnInit, } from '@angular/core';
import { sampleData } from './datasource';
import { TooltipComponent, TooltipEventArgs , TooltipAllModule} from "@syncfusion/ej2-angular-popups";

@Component({
    imports: [TreeGridModule,  TooltipAllModule],
    providers: [PageService, SortService, FilterService],
    standalone: true,
    selector: 'app-container',
    template: `  <ejs-tooltip #tooltip (beforeRender)="beforeRender($event)" target=".e-headertext">
                    <ejs-treegrid #treegrid [dataSource]='data' height='250' [treeColumnIndex]='1' childMapping='subtasks'  [allowFiltering]="true" [allowSorting]="true">
                      <e-columns>
                          <e-column field='taskID' headerText='Task ID' [allowSorting]="false" textAlign='Right' width=120></e-column>
                          <e-column field='taskName' headerText='Task Name' textAlign='Left' width=180></e-column>
                          <e-column field='startDate' headerText='Start Date' [allowFiltering]="false" textAlign='Right' format='yMd' width=120></e-column>
                          <e-column field='duration' headerText='Duration' textAlign='Right' width=120></e-column>
                          <e-column field='progress' headerText='Progress' textAlign='Right' width=120></e-column>
                      </e-columns>
                    </ejs-treegrid> 
                </ejs-tooltip>`,
})
export class AppComponent implements OnInit {

    public data?: Object[];
    @ViewChild('tooltip')
    public toolTip?: TooltipComponent;
    public columnDescriptions: { [key: string]: string } = {
        "Task ID": "A unique number assigned to each task.",
        "Task Name": "The process of the task name.",
        "Duration": "The duration of the task.",
        "Progress": "The progress state of the task.",
        "Start Date": "The date when the order was placed.",
    };
    ngOnInit(): void {
        this.data = sampleData;
    }
    beforeRender(args: TooltipEventArgs) {
        const description = this.columnDescriptions[args.target.innerText];
        if (description) {
            (this.toolTip as TooltipComponent).content = args.target.innerText + ": " + description;
        }
    }
}
import { bootstrapApplication } from '@angular/platform-browser';
import { AppComponent } from './app.component';
import 'zone.js';
bootstrapApplication(AppComponent).catch((err) => console.error(err));

  • The headerCellInfo event can also be used to customize the header tooltip. This event is triggered for each header cell after it is rendered.

Customize header text styles

Customizing the tree grid header styles allows you to modify the appearance of the column header in the Tree Grid control to meet your design requirements. You can customize the font, background color, and other styles of the header cells. To customize the header styles in the tree grid, you can use CSS, properties, methods, or event support provided by the Syncfusion Angular TreeGrid component.

Using CSS

You can apply styles to the header cells using CSS selectors. The Tree Grid provides a class name for each header cell element, which you can use to apply styles to that specific header cell. The .e-headercell class can be used to change the background color and text color of the column header.

  .e-treegrid .e-headercell {
    background-color: #a2d6f4;
    color:rgb(3, 2, 2);
  }

Here’s an example that demonstrates how to customize the appearance of a specific column header in the tree grid using className.

import { NgModule, ViewChild, ViewEncapsulation } 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 { Component, OnInit, } from '@angular/core';
import { sampleData } from './datasource';
@Component({
    imports: [TreeGridModule,],
    encapsulation:ViewEncapsulation.None,
    providers: [PageService, SortService, FilterService],
    standalone: true,
    selector: 'app-container',
    template: `<ejs-treegrid #treegrid [dataSource]='data' height='250' [treeColumnIndex]='1' childMapping='subtasks'>
                 <e-columns>
                    <e-column field='taskID' headerText='Task ID' textAlign='Right' width=120></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=120></e-column>
                    <e-column field='progress' headerText='Progress' textAlign='Right' width=120></e-column>
                 </e-columns>
               </ejs-treegrid>`,
    styles:[`  .e-treegrid .e-headercell {
        background-color: #a2d6f4;
        color:rgb(3, 2, 2);
      }
      `]
})
export class AppComponent implements OnInit {

    public data?: Object[];

    ngOnInit(): void {
        this.data = sampleData;
    }
}
import { bootstrapApplication } from '@angular/platform-browser';
import { AppComponent } from './app.component';
import 'zone.js';
bootstrapApplication(AppComponent).catch((err) => console.error(err));

Using property

You can customize the appearance of the column headers in Tree Grid using the customAttributes property. The customAttributes property takes an object with the name-value pair to customize the CSS properties for tree grid header cells. You can also set multiple CSS properties to the custom class using the customAttributes property.

To customize the header of a column, you can follow the steps below:

Step 1: Define a CSS class that specifies the styles you want to apply to the header cell of the column. For example, to change the background color and text color of the header cell, define a CSS class like this:

    .e-treegrid .e-headercell.customcss {
       background-color: rgb(43, 205, 226);
      color: black;
    }

Step 2: Set the customAttributes property of the desired column to an object that contains the CSS class customcss. This CSS class will be applied to the header cell of the specified column in the tree grid.

     <e-column field='taskID' headerText='Task ID' textAlign='Right' [customAttributes]="{class:'customcss'}" width=120></e-column>

The following example demonstrates how to customize the appearance of the TaskID column using custom attributes.

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 { Component, OnInit, ViewEncapsulation } from '@angular/core';
import { sampleData } from './datasource';
@Component({
    imports: [TreeGridModule,],
    providers: [PageService, SortService, FilterService],
    standalone: true,
    encapsulation: ViewEncapsulation.None,
    selector: 'app-container',
    template: `<ejs-treegrid #treegrid [dataSource]='data' height='250' [treeColumnIndex]='1' childMapping='subtasks'>
                 <e-columns>
                    <e-column field='taskID' headerText='Task ID' textAlign='Right' [customAttributes]="{class:'customcss'}" width=120></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'[customAttributes]="{class:'customcss'}" width=120></e-column>
                    <e-column field='progress' headerText='Progress' textAlign='Right' width=120></e-column>
                  </e-columns>
                </ejs-treegrid>`,
    styleUrls: ['./custom-column.style.css']
})
export class AppComponent implements OnInit {

    public data?: Object[];

    ngOnInit(): void {
        this.data = sampleData;
    }
}
import { bootstrapApplication } from '@angular/platform-browser';
import { AppComponent } from './app.component';
import 'zone.js';
bootstrapApplication(AppComponent).catch((err) => console.error(err));

Using method

The Syncfusion TreeGrid component provides methods to customize the appearance of the tree grid columns header.

  1. getColumnHeaderByIndex: The method is used to customize the appearance of a specific column header in the tree grid by specifying the index of the column for which you want to customize the header.

  2. getColumnHeaderByField: This method is used to retrieve the header element of a specific column by its field name. You can use the retrieved element to customize the appearance of the header element.

  3. getColumnHeaderByUid: This method is used to retrieve the header element of a specific column by its unique ID. You can use the retrieved element to customize the appearance of the header element.

  4. getColumnIndexByField:This method is used to retrieve the index of a specific column by its field name. You can use the retrieved index to access the header element and customize its appearance.

  5. getColumnIndexByUid: This method is used to retrieve the index of a specific column by its unique ID. You can use the retrieved index to access the header element and customize its appearance.

Here’s an example of how to use these methods to change the style of a specific column header:

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

@Component({
    imports: [TreeGridModule,],
    encapsulation: ViewEncapsulation.None,
    providers: [PageService, SortService, FilterService],
    standalone: true,
    selector: 'app-container',
    template: `<ejs-treegrid #treegrid [dataSource]='data' height='250' (dataBound)="dataBound()" [treeColumnIndex]='1' childMapping='subtasks'>
                 <e-columns>
                    <e-column field='taskID' headerText='Task ID' textAlign='Right' [customAttributes]="{class:'customcss'}" width=120></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'[customAttributes]="{class:'customcss'}" width=120></e-column>
                    <e-column field='progress' headerText='Progress' textAlign='Right' width=120></e-column>
                </e-columns>
            </ejs-treegrid>`,
})
export class AppComponent implements OnInit {

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

    ngOnInit(): void {
        this.data = sampleData;
    }
    dataBound() {
        ((this.treegrid as TreeGridComponent).getColumnHeaderByIndex(0) as HTMLElement).style.color = '#0d0b0b';
        ((this.treegrid as TreeGridComponent).getColumnHeaderByField('taskName') as HTMLElement).style.background = '#f45ddeab';
        ((this.treegrid as TreeGridComponent).getColumnHeaderByField('taskName') as HTMLElement).style.color = '#0d0b0b';
        ((this.treegrid as TreeGridComponent).getColumnHeaderByUid('grid-column39') as HTMLElement).style.background = '#f45ddeab';
        const columnIndex = (this.treegrid as TreeGridComponent).getColumnIndexByField('duration');
        ((this.treegrid as TreeGridComponent).getColumnHeaderByIndex(columnIndex) as HTMLElement).style.color = '#0d0b0b';
        const index = (this.treegrid as TreeGridComponent).getColumnIndexByUid('grid-column39');
        ((this.treegrid as TreeGridComponent).getColumnHeaderByIndex(index) as HTMLElement).style.color = '#0d0b0b';
    }
}
import { bootstrapApplication } from '@angular/platform-browser';
import { AppComponent } from './app.component';
import 'zone.js';
bootstrapApplication(AppComponent).catch((err) => console.error(err));

  • The UID is automatically generated by the TreeGrid component and may change whenever the tree grid is refreshed or updated.

Using event

To customize the appearance of the tree grid header, you can handle the headerCellInfo event of the tree grid. This event is triggered when each header cell is rendered in the tree grid, and provides an object that contains information about the header cell. You can use this object to modify the styles of the header column.

The following example demonstrates how to add a headerCellInfo event handler to the tree grid. In the event handler, checked whether the current header column is Start Date field and then applied the appropriate CSS class to the cell based on its value.

import { NgModule, ViewEncapsulation } 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 { HeaderCellInfoEventArgs } from '@syncfusion/ej2-grids';
import { Component, OnInit, ViewChild } from '@angular/core';
import { sampleData } from './datasource';
import { Column, } from '@syncfusion/ej2-treegrid';
@Component({
    imports: [TreeGridModule,],
    providers: [PageService, SortService, FilterService],
    standalone: true,
    selector: 'app-container',
    encapsulation: ViewEncapsulation.None,
    template: `<ejs-treegrid #treegrid [dataSource]='data' height='250' [treeColumnIndex]='1' childMapping='subtasks'  (headerCellInfo)="onHeaderCellInfo($event)">
                  <e-columns>
                    <e-column field='taskID' headerText='Task ID' [allowSorting]="false" textAlign='Right' width=120></e-column>
                    <e-column field='taskName' headerText='Task Name' textAlign='Left' width=180></e-column>
                    <e-column field='startDate' headerText='Start Date' [allowFiltering]="false" textAlign='Right' format='yMd' width=120></e-column>
                    <e-column field='duration' headerText='Duration' textAlign='Right' width=120></e-column>
                    <e-column field='progress' headerText='Progress' textAlign='Right' width=120></e-column>
                  </e-columns>
                </ejs-treegrid>`,
    styles: [`
        .e-treegrid .e-headercell.customcss {
              background-color: #a2d6f4;
              color:rgb(3, 2, 2);
              }`]
})
export class AppComponent implements OnInit {

    public data?: Object[];

    ngOnInit(): void {
        this.data = sampleData;
    }
    public onHeaderCellInfo(args: HeaderCellInfoEventArgs) {
        if ((args.cell as any).column.field == 'startDate') {
            (args.node as Element).classList.add('customcss');
        }
    }
}
import { bootstrapApplication } from '@angular/platform-browser';
import { AppComponent } from './app.component';
import 'zone.js';
bootstrapApplication(AppComponent).catch((err) => console.error(err));

How to refresh header

The refresh header feature in the Syncfusion Angular Tree Grid allows you to update the header section of the tree grid whenever changes are made to the tree grid’s columns. This feature is useful when you want to reflect changes in the header immediately, such as modifying the column header text, width, or alignment.

To use the refresh header feature, you can call the refreshHeader method of the TreeGrid component. This method updates the tree grid header with the latest changes made to the columns.

The following example demonstrates how to use the refreshHeader method to update the tree grid header:

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 { ButtonModule } from '@syncfusion/ej2-angular-buttons'
import { Component, OnInit } from '@angular/core';
import { sampleData } from './datasource';
import { TreeGridComponent } from '@syncfusion/ej2-angular-treegrid';
@Component({
    imports: [TreeGridModule, ButtonModule],
    providers: [PageService, SortService, FilterService],
    standalone: true,
    selector: 'app-container',
    template: ` <button ejs-button (click)="refreshHeader()">Refresh Header</button>
                <ejs-treegrid #treegrid [dataSource]='data' height='250' [treeColumnIndex]='1' childMapping='subtasks'>
                  <e-columns>
                    <e-column field='taskID' headerText='Task ID' textAlign='Right' width=120></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=120></e-column>
                    <e-column field='progress' headerText='Progress' textAlign='Right' width=120></e-column>
                   </e-columns>
                </ejs-treegrid>`,
})
export class AppComponent implements OnInit {

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

    ngOnInit(): void {
        this.data = sampleData;
    }
    public refreshHeader(): void {
        const column = (this.treegrid as TreeGridComponent).grid.getColumnByIndex(1);
        column.headerText = 'New Header Text'; // update the header text of the column object
        (this.treegrid as TreeGridComponent).refreshHeader(); // refresh the grid header
    }
}
import { bootstrapApplication } from '@angular/platform-browser';
import { AppComponent } from './app.component';
import 'zone.js';
bootstrapApplication(AppComponent).catch((err) => console.error(err));

  • The refreshHeader method updates only the tree grid header and not the entire tree grid.
  • If you want to refresh the entire tree grid, you can use the refresh method instead.

How to get header element

To get the header element in a Syncfusion Tree Grid, you can use one of the following methods:

  1. getHeaderContent: This method returns the header div element of the tree grid. You can use this method to access the entire header content of the tree grid.

     const headerElement = this.treegrid.getHeaderContent();

  2. getHeaderTable: This method returns the header table element of the tree grid. You can use this method to access only the header table of the tree grid.

     const headerTableElement = this.treegrid.getHeaderTable();

  3. getColumnHeaderByUid: This method returns the column header element by its unique identifier.

     const columnHeaderElement = this.treegrid.getColumnHeaderByUid("e-treegrid2");

  4. getColumnHeaderByIndex: This method returns the column header element by its index.

     const columnHeaderElement = this.treegrid.getColumnHeaderByIndex(0);

  5. getColumnHeaderByField: This method returns the column header element by its field name.

     const columnHeaderElement = this.treegrid.getColumnHeaderByField("taskID");
  • The UID is automatically generated by the TreeGrid component and may change whenever the tree grid is refreshed or updated.