Hierarchy grid in EJ2 TypeScript Grid control

4 Aug 202324 minutes to read

The Grid allows display of table data in a hierarchical structure to visualize relations between parent and child records. This feature is enabled by defining the childGrid and childGrid.queryString. The childGrid describes the options of grid and the childGrid.queryString describes the relation between parent and child grids.

To use hierarchical binding, inject the DetailRow module in the grid.

index.ts
index.html
import { Grid, DetailRow } from '@syncfusion/ej2-grids';
import { data } from './datasource.ts';
import { employeeData } from './employeeData.ts';

Grid.Inject(DetailRow);

let grid: Grid = new Grid({
    dataSource: employeeData,
    columns: [
        { field: 'EmployeeID', headerText: 'Employee ID', textAlign: 'Right', width: 120 },
        { field: 'FirstName', headerText: 'First Name', width: 150 },
        { field: 'City', headerText: 'City', width: 150 },
        { field: 'Country', headerText: 'Country', width: 150 }
    ],
    childGrid: {
        dataSource: data,
        queryString: 'EmployeeID',
        columns: [
            { field: 'OrderID', headerText: 'Order ID', textAlign: 'Right', width: 120 },
            { field: 'CustomerID', headerText: 'Customer ID', width: 150 },
            { field: 'ShipCity', headerText: 'Ship City', width: 150 },
            { field: 'ShipName', headerText: 'Ship Name', width: 150 }
        ],
    },
    height: 315
});
grid.appendTo('#Grid');
<!DOCTYPE html>
<html lang="en">

<head>
    <title>EJ2 Grid</title>
    <meta charset="utf-8" />
    <meta name="viewport" content="width=device-width, initial-scale=1.0" />
    <meta name="description" content="Typescript Grid Control" />
    <meta name="author" content="Syncfusion" />
    <link href="index.css" rel="stylesheet" />
    <link href="https://cdn.syncfusion.com/ej2/23.1.36/ej2-base/styles/material.css" rel="stylesheet" />
    <link href="https://cdn.syncfusion.com/ej2/23.1.36/ej2-grids/styles/material.css" rel="stylesheet" />
    <link href="https://cdn.syncfusion.com/ej2/23.1.36/ej2-buttons/styles/material.css" rel="stylesheet" />
    <link href="https://cdn.syncfusion.com/ej2/23.1.36/ej2-popups/styles/material.css" rel="stylesheet" />
    <link href="https://cdn.syncfusion.com/ej2/23.1.36/ej2-richtexteditor/styles/material.css" rel="stylesheet" />
    <link href="https://cdn.syncfusion.com/ej2/23.1.36/ej2-navigations/styles/material.css" rel="stylesheet" />
    <link href="https://cdn.syncfusion.com/ej2/23.1.36/ej2-dropdowns/styles/material.css" rel="stylesheet" />
    <link href="https://cdn.syncfusion.com/ej2/23.1.36/ej2-lists/styles/material.css" rel="stylesheet" />
    <link href="https://cdn.syncfusion.com/ej2/23.1.36/ej2-inputs/styles/material.css" rel="stylesheet" />
    <link href="https://cdn.syncfusion.com/ej2/23.1.36/ej2-calendars/styles/material.css" rel="stylesheet" />
    <link href="https://cdn.syncfusion.com/ej2/23.1.36/ej2-notifications/styles/material.css" rel="stylesheet" />
    <link href="https://cdn.syncfusion.com/ej2/23.1.36/ej2-splitbuttons/styles/material.css" rel="stylesheet" />

    <script src="https://cdnjs.cloudflare.com/ajax/libs/systemjs/0.19.38/system.js"></script>
    <script src="systemjs.config.js"></script>
    <style>
        .e-row[aria-selected="true"] .e-customizedExpandcell {
            background-color: #e0e0e0;
        }
        .e-grid.e-gridhover tr[role='row']:hover {
            background-color: #eee;
        }
        .e-expand::before {
        content: '\e5b8';
    }
    .empImage {
        margin: 6px 16px;
        float: left;
        width: 50px;
        height: 50px;
    }
    </style>
<script src="https://cdn.syncfusion.com/ej2/syncfusion-helper.js" type ="text/javascript"></script>
</head>
<body>
    <div id='loader'>Loading....</div>
    <div id='container'>
        <div id='Grid'></div>
    </div>
</body>
</html>

Grid supports n level of child grids.

Hierarchical binding is not supported when DetailTemplate is enabled.

ExpandAll by external button

By default, grid renders in collapsed state. You can expand all child grid rows by invoking the expandAll method, and collapse all grid rows by invoking the collapseAll through an external button.

index.ts
index.html
import { Grid, DetailRow } from '@syncfusion/ej2-grids';
import { Button } from '@syncfusion/ej2-buttons';
import { data, employeeData } from './datasource.ts';

Grid.Inject(DetailRow);

let expandBtn: Button = new Button();
expandBtn.appendTo('#expandall');

let collapseBtn: Button = new Button();
collapseBtn.appendTo('#collapseall');

let grid: Grid = new Grid({
    dataSource: employeeData,
    columns: [
        { field: 'EmployeeID', headerText: 'Employee ID', textAlign: 'Right', width: 120 },
        { field: 'FirstName', headerText: 'First Name', width: 150 },
        { field: 'City', headerText: 'City', width: 150 },
        { field: 'Country', headerText: 'Country', width: 150 }
    ],
    childGrid: {
        dataSource: data,
        queryString: 'EmployeeID',
        columns: [
            { field: 'OrderID', headerText: 'Order ID', textAlign: 'Right', width: 120 },
            { field: 'CustomerID', headerText: 'Customer ID', width: 150 },
            { field: 'ShipCity', headerText: 'Ship City', width: 150 },
            { field: 'ShipName', headerText: 'Ship Name', width: 150 }
        ],
    },
    height: 265
});
grid.appendTo('#Grid');

document.getElementById('expandall').addEventListener('click', () => {
    grid.detailRowModule.expandAll();
});
document.getElementById('collapseall').addEventListener('click', () => {
    grid.detailRowModule.collapseAll();
});
<!DOCTYPE html>
<html lang="en">

<head>
    <title>EJ2 Grid</title>
    <meta charset="utf-8" />
    <meta name="viewport" content="width=device-width, initial-scale=1.0" />
    <meta name="description" content="Typescript Grid Control" />
    <meta name="author" content="Syncfusion" />
    <link href="index.css" rel="stylesheet" />
    <link href="https://cdn.syncfusion.com/ej2/23.1.36/ej2-base/styles/material.css" rel="stylesheet" />
    <link href="https://cdn.syncfusion.com/ej2/23.1.36/ej2-grids/styles/material.css" rel="stylesheet" />
    <link href="https://cdn.syncfusion.com/ej2/23.1.36/ej2-buttons/styles/material.css" rel="stylesheet" />
    <link href="https://cdn.syncfusion.com/ej2/23.1.36/ej2-popups/styles/material.css" rel="stylesheet" />
    <link href="https://cdn.syncfusion.com/ej2/23.1.36/ej2-navigations/styles/material.css" rel="stylesheet" />
    <link href="https://cdn.syncfusion.com/ej2/23.1.36/ej2-dropdowns/styles/material.css" rel="stylesheet" />
    <link href="https://cdn.syncfusion.com/ej2/23.1.36/ej2-lists/styles/material.css" rel="stylesheet" />
    <link href="https://cdn.syncfusion.com/ej2/23.1.36/ej2-inputs/styles/material.css" rel="stylesheet" />
    <link href="https://cdn.syncfusion.com/ej2/23.1.36/ej2-calendars/styles/material.css" rel="stylesheet" />
    
    
    
    <link href="https://cdn.syncfusion.com/ej2/23.1.36/ej2-splitbuttons/styles/material.css" rel="stylesheet" />
    
    
    <script src="https://cdnjs.cloudflare.com/ajax/libs/systemjs/0.19.38/system.js"></script>
    <script src="systemjs.config.js"></script>
<script src="https://cdn.syncfusion.com/ej2/syncfusion-helper.js" type ="text/javascript"></script>
</head>
<body>
    <div id='loader'>Loading....</div>
    <div id='container'>
        <button id="expandall">Expand All</button> 
        <button id="collapseall">Collapse All</button>        
        <div id='Grid'></div>        
    </div>
</body>
</html>

Expand child grid initially

You can expand a particular child grid at initial rendering by invoking the expand method in the dataBound event.

index.ts
index.html
import { Grid, DetailRow } from '@syncfusion/ej2-grids';
import { data } from './datasource.ts';
import { employeeData } from './employeeData.ts';

Grid.Inject(DetailRow);

let grid: Grid = new Grid({
    dataSource: employeeData,
    columns: [
        { field: 'EmployeeID', headerText: 'Employee ID', textAlign: 'Right', width: 120 },
        { field: 'FirstName', headerText: 'First Name', width: 150 },
        { field: 'City', headerText: 'City', width: 150 },
        { field: 'Country', headerText: 'Country', width: 150 }
    ],
    childGrid: {
        dataSource: data,
        queryString: 'EmployeeID',
        columns: [
            { field: 'OrderID', headerText: 'Order ID', textAlign: 'Right', width: 120 },
            { field: 'CustomerID', headerText: 'Customer ID', width: 150 },
            { field: 'ShipCity', headerText: 'Ship City', width: 150 },
            { field: 'ShipName', headerText: 'Ship Name', width: 150 }
        ],
    },
    height: 315,
    dataBound: onDataBound
});
grid.appendTo('#Grid');

function onDataBound(): void {
    this.detailRowModule.expand(1); // initial expand 1 chid Grid.
}
<!DOCTYPE html>
<html lang="en">

<head>
    <title>EJ2 Grid</title>
    <meta charset="utf-8" />
    <meta name="viewport" content="width=device-width, initial-scale=1.0" />
    <meta name="description" content="Typescript Grid Control" />
    <meta name="author" content="Syncfusion" />
    <link href="index.css" rel="stylesheet" />
    <link href="https://cdn.syncfusion.com/ej2/23.1.36/ej2-base/styles/material.css" rel="stylesheet" />
    <link href="https://cdn.syncfusion.com/ej2/23.1.36/ej2-grids/styles/material.css" rel="stylesheet" />
    <link href="https://cdn.syncfusion.com/ej2/23.1.36/ej2-buttons/styles/material.css" rel="stylesheet" />
    <link href="https://cdn.syncfusion.com/ej2/23.1.36/ej2-popups/styles/material.css" rel="stylesheet" />
    <link href="https://cdn.syncfusion.com/ej2/23.1.36/ej2-richtexteditor/styles/material.css" rel="stylesheet" />
    <link href="https://cdn.syncfusion.com/ej2/23.1.36/ej2-navigations/styles/material.css" rel="stylesheet" />
    <link href="https://cdn.syncfusion.com/ej2/23.1.36/ej2-dropdowns/styles/material.css" rel="stylesheet" />
    <link href="https://cdn.syncfusion.com/ej2/23.1.36/ej2-lists/styles/material.css" rel="stylesheet" />
    <link href="https://cdn.syncfusion.com/ej2/23.1.36/ej2-inputs/styles/material.css" rel="stylesheet" />
    <link href="https://cdn.syncfusion.com/ej2/23.1.36/ej2-calendars/styles/material.css" rel="stylesheet" />
    <link href="https://cdn.syncfusion.com/ej2/23.1.36/ej2-notifications/styles/material.css" rel="stylesheet" />
    <link href="https://cdn.syncfusion.com/ej2/23.1.36/ej2-splitbuttons/styles/material.css" rel="stylesheet" />

    <script src="https://cdnjs.cloudflare.com/ajax/libs/systemjs/0.19.38/system.js"></script>
    <script src="systemjs.config.js"></script>
    <style>
        .e-row[aria-selected="true"] .e-customizedExpandcell {
            background-color: #e0e0e0;
        }
        .e-grid.e-gridhover tr[role='row']:hover {
            background-color: #eee;
        }
        .e-expand::before {
        content: '\e5b8';
    }
    .empImage {
        margin: 6px 16px;
        float: left;
        width: 50px;
        height: 50px;
    }
    </style>
<script src="https://cdn.syncfusion.com/ej2/syncfusion-helper.js" type ="text/javascript"></script>
</head>
<body>
    <div id='loader'>Loading....</div>
    <div id='container'>
        <div id='Grid'></div>
    </div>
</body>
</html>

Dynamically load child grid data

You can dynamically load child grid dataSource by using the load event. This load event triggers when the child grid is expanded for the first time.

index.ts
index.html
import { Grid, DetailRow } from '@syncfusion/ej2-grids';
import { data } from './datasource.ts';
import { employeeData } from './employeeData.ts';

Grid.Inject(DetailRow);

let grid: Grid = new Grid({
    dataSource: employeeData,
    columns: [
        { field: 'EmployeeID', headerText: 'Employee ID', textAlign: 'Right', width: 120 },
        { field: 'FirstName', headerText: 'First Name', width: 150 },
        { field: 'City', headerText: 'City', width: 150 },
        { field: 'Country', headerText: 'Country', width: 150 }
    ],
    childGrid: {
        queryString: 'EmployeeID',
        columns: [
            { field: 'OrderID', headerText: 'Order ID', textAlign: 'Right', width: 120 },
            { field: 'CustomerID', headerText: 'Customer ID', width: 150 },
            { field: 'ShipCity', headerText: 'Ship City', width: 150 },
            { field: 'ShipName', headerText: 'Ship Name', width: 150 }
        ],
        load: onLoad
    },
    height: 315
});
grid.appendTo('#Grid');

function onLoad(args: Object): void {
    this.dataSource = data; // assign data source for child grid.
}
<!DOCTYPE html>
<html lang="en">

<head>
    <title>EJ2 Grid</title>
    <meta charset="utf-8" />
    <meta name="viewport" content="width=device-width, initial-scale=1.0" />
    <meta name="description" content="Typescript Grid Control" />
    <meta name="author" content="Syncfusion" />
    <link href="index.css" rel="stylesheet" />
    <link href="https://cdn.syncfusion.com/ej2/23.1.36/ej2-base/styles/material.css" rel="stylesheet" />
    <link href="https://cdn.syncfusion.com/ej2/23.1.36/ej2-grids/styles/material.css" rel="stylesheet" />
    <link href="https://cdn.syncfusion.com/ej2/23.1.36/ej2-buttons/styles/material.css" rel="stylesheet" />
    <link href="https://cdn.syncfusion.com/ej2/23.1.36/ej2-popups/styles/material.css" rel="stylesheet" />
    <link href="https://cdn.syncfusion.com/ej2/23.1.36/ej2-richtexteditor/styles/material.css" rel="stylesheet" />
    <link href="https://cdn.syncfusion.com/ej2/23.1.36/ej2-navigations/styles/material.css" rel="stylesheet" />
    <link href="https://cdn.syncfusion.com/ej2/23.1.36/ej2-dropdowns/styles/material.css" rel="stylesheet" />
    <link href="https://cdn.syncfusion.com/ej2/23.1.36/ej2-lists/styles/material.css" rel="stylesheet" />
    <link href="https://cdn.syncfusion.com/ej2/23.1.36/ej2-inputs/styles/material.css" rel="stylesheet" />
    <link href="https://cdn.syncfusion.com/ej2/23.1.36/ej2-calendars/styles/material.css" rel="stylesheet" />
    <link href="https://cdn.syncfusion.com/ej2/23.1.36/ej2-notifications/styles/material.css" rel="stylesheet" />
    <link href="https://cdn.syncfusion.com/ej2/23.1.36/ej2-splitbuttons/styles/material.css" rel="stylesheet" />

    <script src="https://cdnjs.cloudflare.com/ajax/libs/systemjs/0.19.38/system.js"></script>
    <script src="systemjs.config.js"></script>
    <style>
        .e-row[aria-selected="true"] .e-customizedExpandcell {
            background-color: #e0e0e0;
        }
        .e-grid.e-gridhover tr[role='row']:hover {
            background-color: #eee;
        }
        .e-expand::before {
        content: '\e5b8';
    }
    .empImage {
        margin: 6px 16px;
        float: left;
        width: 50px;
        height: 50px;
    }
    </style>
<script src="https://cdn.syncfusion.com/ej2/syncfusion-helper.js" type ="text/javascript"></script>
</head>
<body>
    <div id='loader'>Loading....</div>
    <div id='container'>
        <div id='Grid'></div>
    </div>
</body>
</html>

Bind hierarchy grid with different field

By default, Parent and child grid relation will be maintained by queryString property. We should use the same field name to map both parent and child grid. To achieve parent and child relation with different fields, we need to change the mapping value in the child grid load event.

In the below sample, we have bound the child and parent grid with different fields. Parent grid field name as EmployeeID and the child grid field name as ID. We need to define the mapping value of parentKeyFieldValue from the parent row data in the child grid load event.

index.ts
index.html
import { Grid, DetailRow } from '@syncfusion/ej2-grids';
import { data } from './childdata.ts';
import { employeeData } from './employeeData.ts';

Grid.Inject(DetailRow);

let grid: Grid = new Grid({
    dataSource: employeeData,
    columns: [
        { field: 'EmployeeID', headerText: 'Employee ID', textAlign: 'Right', width: 120 },
        { field: 'FirstName', headerText: 'First Name', width: 150 },
        { field: 'City', headerText: 'City', width: 150 },
        { field: 'Country', headerText: 'Country', width: 150 }
    ],
    childGrid: {
        dataSource: data,
        queryString: 'ID',
        columns: [
            { field: 'ID', headerText: 'Order ID', textAlign: 'Right', width: 120 },
            { field: 'CustomerID', headerText: 'Customer ID', width: 150 },
            { field: 'ShipCity', headerText: 'Ship City', width: 150 },
            { field: 'ShipName', headerText: 'Ship Name', width: 150 }
        ],
        load: onLoad,
    },
    height: 315
});
grid.appendTo('#Grid');

function onLoad(): void {
  this.parentDetails.parentKeyFieldValue = this.parentDetails.parentRowData['EmployeeID'];
}
<!DOCTYPE html>
<html lang="en">

<head>
    <title>EJ2 Grid</title>
    <meta charset="utf-8" />
    <meta name="viewport" content="width=device-width, initial-scale=1.0" />
    <meta name="description" content="Typescript Grid Control" />
    <meta name="author" content="Syncfusion" />
    <link href="index.css" rel="stylesheet" />
    <link href="https://cdn.syncfusion.com/ej2/23.1.36/ej2-base/styles/material.css" rel="stylesheet" />
    <link href="https://cdn.syncfusion.com/ej2/23.1.36/ej2-grids/styles/material.css" rel="stylesheet" />
    <link href="https://cdn.syncfusion.com/ej2/23.1.36/ej2-buttons/styles/material.css" rel="stylesheet" />
    <link href="https://cdn.syncfusion.com/ej2/23.1.36/ej2-popups/styles/material.css" rel="stylesheet" />
    <link href="https://cdn.syncfusion.com/ej2/23.1.36/ej2-richtexteditor/styles/material.css" rel="stylesheet" />
    <link href="https://cdn.syncfusion.com/ej2/23.1.36/ej2-navigations/styles/material.css" rel="stylesheet" />
    <link href="https://cdn.syncfusion.com/ej2/23.1.36/ej2-dropdowns/styles/material.css" rel="stylesheet" />
    <link href="https://cdn.syncfusion.com/ej2/23.1.36/ej2-lists/styles/material.css" rel="stylesheet" />
    <link href="https://cdn.syncfusion.com/ej2/23.1.36/ej2-inputs/styles/material.css" rel="stylesheet" />
    <link href="https://cdn.syncfusion.com/ej2/23.1.36/ej2-calendars/styles/material.css" rel="stylesheet" />
    <link href="https://cdn.syncfusion.com/ej2/23.1.36/ej2-notifications/styles/material.css" rel="stylesheet" />
    <link href="https://cdn.syncfusion.com/ej2/23.1.36/ej2-splitbuttons/styles/material.css" rel="stylesheet" />

    <script src="https://cdnjs.cloudflare.com/ajax/libs/systemjs/0.19.38/system.js"></script>
    <script src="systemjs.config.js"></script>
    <style>
        .e-row[aria-selected="true"] .e-customizedExpandcell {
            background-color: #e0e0e0;
        }
        .e-grid.e-gridhover tr[role='row']:hover {
            background-color: #eee;
        }
        .e-expand::before {
        content: '\e5b8';
    }
    .empImage {
        margin: 6px 16px;
        float: left;
        width: 50px;
        height: 50px;
    }
    </style>
<script src="https://cdn.syncfusion.com/ej2/syncfusion-helper.js" type ="text/javascript"></script>
</head>
<body>
    <div id='loader'>Loading....</div>
    <div id='container'>
        <div id='Grid'></div>
    </div>
</body>
</html>

Adding Record in ChildGrid

Parent and child grid are related by queryString field value. To maintain this relation in newly added record, You need to set value for queryString field in the added data by the actionBegin event.

In the below demo, EmployeeID field relates the parent and child grids. To add a new record in child grid, We have to set the EmployeeID field with parent record’s queryString field value in the actionBegin event.

index.ts
index.html
import { Grid, DetailRow, AddEventArgs, Edit, Toolbar } from '@syncfusion/ej2-grids';
import { data } from './datasource.ts';
import { employeeData } from './employeeData.ts';

Grid.Inject(DetailRow, Edit, Toolbar);

let grid: Grid = new Grid({
    dataSource: employeeData,
    columns: [
        { field: 'EmployeeID', headerText: 'Employee ID', textAlign: 'Right', width: 120 },
        { field: 'FirstName', headerText: 'First Name', width: 150 },
        { field: 'City', headerText: 'City', width: 150 },
        { field: 'Country', headerText: 'Country', width: 150 }
    ],
    childGrid: {
        dataSource: data,
        queryString: 'EmployeeID',
        toolbar: ['Add', 'Edit', 'Delete', 'Update', 'Cancel'],
        editSettings: { allowEditing: true, allowAdding: true, allowDeleting: true },
        columns: [
            { field: 'OrderID', headerText: 'Order ID', isPrimaryKey:true, textAlign: 'Right', width: 120 },
            { field: 'EmployeeID', headerText: 'Employee ID', textAlign: 'Right', allowEditing:false, width: 120 },
            { field: 'CustomerID', headerText: 'Customer ID', width: 150 },
            { field: 'ShipName', headerText: 'Ship Name', width: 150 }
        ],
        actionBegin: actionBegin
    },
    height: 315
});
grid.appendTo('#Grid');

function actionBegin(args: AddEventArgs): void {
    if (args.requestType === "add") {
        // `parentKeyFieldValue` refers to the queryString field value of the parent record.
       args.data.EmployeeID = this.parentDetails.parentKeyFieldValue;
    }
}
<!DOCTYPE html>
<html lang="en">

<head>
    <title>EJ2 Grid</title>
    <meta charset="utf-8" />
    <meta name="viewport" content="width=device-width, initial-scale=1.0" />
    <meta name="description" content="Typescript Grid Control" />
    <meta name="author" content="Syncfusion" />
    <link href="index.css" rel="stylesheet" />
    <link href="https://cdn.syncfusion.com/ej2/23.1.36/ej2-base/styles/material.css" rel="stylesheet" />
    <link href="https://cdn.syncfusion.com/ej2/23.1.36/ej2-grids/styles/material.css" rel="stylesheet" />
    <link href="https://cdn.syncfusion.com/ej2/23.1.36/ej2-buttons/styles/material.css" rel="stylesheet" />
    <link href="https://cdn.syncfusion.com/ej2/23.1.36/ej2-popups/styles/material.css" rel="stylesheet" />
    <link href="https://cdn.syncfusion.com/ej2/23.1.36/ej2-richtexteditor/styles/material.css" rel="stylesheet" />
    <link href="https://cdn.syncfusion.com/ej2/23.1.36/ej2-navigations/styles/material.css" rel="stylesheet" />
    <link href="https://cdn.syncfusion.com/ej2/23.1.36/ej2-dropdowns/styles/material.css" rel="stylesheet" />
    <link href="https://cdn.syncfusion.com/ej2/23.1.36/ej2-lists/styles/material.css" rel="stylesheet" />
    <link href="https://cdn.syncfusion.com/ej2/23.1.36/ej2-inputs/styles/material.css" rel="stylesheet" />
    <link href="https://cdn.syncfusion.com/ej2/23.1.36/ej2-calendars/styles/material.css" rel="stylesheet" />
    <link href="https://cdn.syncfusion.com/ej2/23.1.36/ej2-notifications/styles/material.css" rel="stylesheet" />
    <link href="https://cdn.syncfusion.com/ej2/23.1.36/ej2-splitbuttons/styles/material.css" rel="stylesheet" />

    <script src="https://cdnjs.cloudflare.com/ajax/libs/systemjs/0.19.38/system.js"></script>
    <script src="systemjs.config.js"></script>
    <style>
        .e-row[aria-selected="true"] .e-customizedExpandcell {
            background-color: #e0e0e0;
        }
        .e-grid.e-gridhover tr[role='row']:hover {
            background-color: #eee;
        }
        .e-expand::before {
        content: '\e5b8';
    }
    .empImage {
        margin: 6px 16px;
        float: left;
        width: 50px;
        height: 50px;
    }
    </style>
<script src="https://cdn.syncfusion.com/ej2/syncfusion-helper.js" type ="text/javascript"></script>
</head>
<body>
    <div id='loader'>Loading....</div>
    <div id='container'>
        <div id='Grid'></div>
    </div>
</body>
</html>

Dynamically bind data to child grid based on parent row Data

By default, the childGrid.queryString describes the relationship between parent and child grids and visualizes the data in a hierarchical structure. Instead of the queryString property, we can dynamically bind the datasource to the childGrid based on the parent row data using the detailDataBound event of the grid.

While expanding the child Grid, the detailDataBound event will be triggered. In this event, based on the EmployeeID column value of parent row data, filter the equally matched data from the childGrid datasource using the DataManager plugin and bind the filtered data as a datasource to the childGrid. This can be demonstrated by the following sample.

index.ts
index.html
import { Grid, DetailRow, DetailDataBoundEventArgs } from '@syncfusion/ej2-grids';
import { data } from './datasource.ts';
import { employeeData } from './employeeData.ts';
import {DataManager,Query} from '@syncfusion/ej2-data';

Grid.Inject(DetailRow);
let orderData = data;
let grid: Grid = new Grid({
    dataSource: employeeData,
    columns: [
        { field: 'EmployeeID', headerText: 'Employee ID', textAlign: 'Right', width: 120 },
        { field: 'FirstName', headerText: 'First Name', width: 150 },
        { field: 'City', headerText: 'City', width: 150 },
        { field: 'Country', headerText: 'Country', width: 150 }
    ],
    childGrid: {
        columns: [
            { field: 'OrderID', headerText: 'Order ID', isPrimaryKey:true, textAlign: 'Right', width: 120 },
            { field: 'EmployeeID', headerText: 'Employee ID', textAlign: 'Right' width: 120 },
            { field: 'CustomerID', headerText: 'Customer ID', width: 150 },
            { field: 'ShipName', headerText: 'Ship Name', width: 150 }
        ],
    },
    height: 315,

    detailDataBound: (args: DetailDataBoundEventArgs) => {
        let empIdValue = args.childGrid.parentDetails.parentRowData.EmployeeID;
        let matchedData = new DataManager(orderData).executeLocal(
            new Query().where('EmployeeID', 'equal', empIdValue, true)
        );
        args.childGrid.query = new Query();
        args.childGrid.dataSource = matchedData;
        }
    });
grid.appendTo('#Grid');
<!DOCTYPE html>
<html lang="en">

<head>
    <title>EJ2 Grid</title>
    <meta charset="utf-8" />
    <meta name="viewport" content="width=device-width, initial-scale=1.0" />
    <meta name="description" content="Typescript Grid Control" />
    <meta name="author" content="Syncfusion" />
    <link href="index.css" rel="stylesheet" />
    <link href="https://cdn.syncfusion.com/ej2/23.1.36/ej2-base/styles/material.css" rel="stylesheet" />
    <link href="https://cdn.syncfusion.com/ej2/23.1.36/ej2-grids/styles/material.css" rel="stylesheet" />
    <link href="https://cdn.syncfusion.com/ej2/23.1.36/ej2-buttons/styles/material.css" rel="stylesheet" />
    <link href="https://cdn.syncfusion.com/ej2/23.1.36/ej2-popups/styles/material.css" rel="stylesheet" />
    <link href="https://cdn.syncfusion.com/ej2/23.1.36/ej2-richtexteditor/styles/material.css" rel="stylesheet" />
    <link href="https://cdn.syncfusion.com/ej2/23.1.36/ej2-navigations/styles/material.css" rel="stylesheet" />
    <link href="https://cdn.syncfusion.com/ej2/23.1.36/ej2-dropdowns/styles/material.css" rel="stylesheet" />
    <link href="https://cdn.syncfusion.com/ej2/23.1.36/ej2-lists/styles/material.css" rel="stylesheet" />
    <link href="https://cdn.syncfusion.com/ej2/23.1.36/ej2-inputs/styles/material.css" rel="stylesheet" />
    <link href="https://cdn.syncfusion.com/ej2/23.1.36/ej2-calendars/styles/material.css" rel="stylesheet" />
    <link href="https://cdn.syncfusion.com/ej2/23.1.36/ej2-notifications/styles/material.css" rel="stylesheet" />
    <link href="https://cdn.syncfusion.com/ej2/23.1.36/ej2-splitbuttons/styles/material.css" rel="stylesheet" />

    <script src="https://cdnjs.cloudflare.com/ajax/libs/systemjs/0.19.38/system.js"></script>
    <script src="systemjs.config.js"></script>
    <style>
        .e-row[aria-selected="true"] .e-customizedExpandcell {
            background-color: #e0e0e0;
        }
        .e-grid.e-gridhover tr[role='row']:hover {
            background-color: #eee;
        }
        .e-expand::before {
        content: '\e5b8';
    }
    .empImage {
        margin: 6px 16px;
        float: left;
        width: 50px;
        height: 50px;
    }
    </style>
<script src="https://cdn.syncfusion.com/ej2/syncfusion-helper.js" type ="text/javascript"></script>
</head>
<body>
    <div id='loader'>Loading....</div>
    <div id='container'>
        <div id='Grid'></div>
    </div>
</body>
</html>