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Data Binding in JavaScript TreeGrid control

13 May 2021 / 20 minutes to read

The TreeGrid uses DataManager, which supports both RESTful JSON data services binding and local JavaScript object array binding. The dataSource property can be assigned either with the instance of DataManager or JavaScript object array collection. It supports two kinds of data binding method:

  • Local data
  • Remote data

Local Data

In Local Data binding, data source for rendering the TreeGrid control is retrieved from the same application locally.

Two types of Data binding are possible with the TreeGrid control.

  • Hierarchical Datasource binding
  • Self-Referential Data binding (Flat Data)

To bind local data to the treegrid, you can assign a JavaScript object array to the dataSource property. The local data source can also be provided as an instance of the DataManager.

By default, DataManager uses JsonAdaptor for local data-binding.

Hierarchy data source binding

The childMapping property is used to map the child records in hierarchy data source.

The following code example shows you how to bind the hierarchical local data into the TreeGrid control.

Source
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index.ts
index.html
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import { TreeGrid, Page } from '@syncfusion/ej2-treegrid';
import { sampleData } from './datasource.ts';
TreeGrid.Inject(Page);

let treeGridObj: TreeGrid = new TreeGrid({
dataSource: sampleData,
childMapping: 'subtasks',
allowPaging: true,
pageSettings: {pageSize: 7},
treeColumnIndex: 1,
columns: [
            { field: 'taskID', headerText: 'Task ID', width: 90, textAlign: 'Right' },
            { field: 'taskName', headerText: 'Task Name', width: 180 },
            {
                field: 'startDate', headerText: 'Start Date', width: 90, textAlign: 'Right', type: 'date',format: 'yMd'
            },
            { field: 'duration', headerText: 'Duration', width: 80, textAlign: 'Right' }
]
});

treeGridObj.appendTo('#TreeGrid');



> * Remote data binding is not supported for Hierarchy Data.
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<!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="//cdn.syncfusion.com/ej2/ej2-base/styles/material.css" rel="stylesheet" />
    <link href="//cdn.syncfusion.com/ej2/ej2-grids/styles/material.css" rel="stylesheet" />
    <link href="//cdn.syncfusion.com/ej2/ej2-treegrid/styles/material.css" rel="stylesheet" />
    <link href="//cdn.syncfusion.com/ej2/ej2-buttons/styles/material.css" rel="stylesheet" />
    <link href="//cdn.syncfusion.com/ej2/ej2-popups/styles/material.css" rel="stylesheet" />
    <link href="//cdn.syncfusion.com/ej2/ej2-navigations/styles/material.css" rel="stylesheet" />
    <link href="//cdn.syncfusion.com/ej2/ej2-dropdowns/styles/material.css" rel="stylesheet" />
    <link href="//cdn.syncfusion.com/ej2/ej2-lists/styles/material.css" rel="stylesheet" />
    <link href="//cdn.syncfusion.com/ej2/ej2-inputs/styles/material.css" rel="stylesheet" />
    <link href="//cdn.syncfusion.com/ej2/ej2-calendars/styles/material.css" rel="stylesheet" />
    
    
    
    <link href="//cdn.syncfusion.com/ej2/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>
</head>
<body>
    <div id='loader'>Loading....</div>
    <div id='container'>
        <div id='TreeGrid'></div>        
    </div>
</body>
</html>

Self-Referential Data binding (Flat Data)

TreeGrid is rendered from Self-Referential data structures by providing two fields, ID field and parent ID field.

  • ID Field: This field contains unique values used to identify nodes. Its name is assigned to the idMapping property.
  • Parent ID Field: This field contains values that indicate parent nodes. Its name is assigned to the parentIdMapping property.
Source
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index.ts
index.html
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import { TreeGrid, Page } from '@syncfusion/ej2-treegrid';
import { projectData } from './datasource.ts';
TreeGrid.Inject(Page);

let treeGridObj: TreeGrid = new TreeGrid({
dataSource: projectData,
idMapping: 'TaskID',
parentIdMapping: 'parentID',
allowPaging: true,
treeColumnIndex: 1,
pageSettings: {pageSize: 7},
columns: [
            { field: 'TaskID', headerText: 'Task ID', width: 90, textAlign: 'Right' },
            { field: 'TaskName', headerText: 'Task Name', width: 180 },
            {
                field: 'StartDate', headerText: 'Start Date', width: 90, textAlign: 'Right', type: 'date',format: 'yMd'
            },
            { field: 'Duration', headerText: 'Duration', width: 80, textAlign: 'Right' }
]
});

treeGridObj.appendTo('#TreeGrid');
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<!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="//cdn.syncfusion.com/ej2/ej2-base/styles/material.css" rel="stylesheet" />
    <link href="//cdn.syncfusion.com/ej2/ej2-grids/styles/material.css" rel="stylesheet" />
    <link href="//cdn.syncfusion.com/ej2/ej2-treegrid/styles/material.css" rel="stylesheet" />
    <link href="//cdn.syncfusion.com/ej2/ej2-buttons/styles/material.css" rel="stylesheet" />
    <link href="//cdn.syncfusion.com/ej2/ej2-popups/styles/material.css" rel="stylesheet" />
    <link href="//cdn.syncfusion.com/ej2/ej2-navigations/styles/material.css" rel="stylesheet" />
    <link href="//cdn.syncfusion.com/ej2/ej2-dropdowns/styles/material.css" rel="stylesheet" />
    <link href="//cdn.syncfusion.com/ej2/ej2-lists/styles/material.css" rel="stylesheet" />
    <link href="//cdn.syncfusion.com/ej2/ej2-inputs/styles/material.css" rel="stylesheet" />
    <link href="//cdn.syncfusion.com/ej2/ej2-calendars/styles/material.css" rel="stylesheet" />
    
    
    
    <link href="//cdn.syncfusion.com/ej2/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>
</head>
<body>
    <div id='loader'>Loading....</div>
    <div id='container'>
        <div id='TreeGrid'></div>        
    </div>
</body>
</html>

Herewith we have provided list of reserved properties and the purpose we used internally in TreeGrid. We recommend to avoid these reserved properties in your dataSource(To get rid of conflicts).

Reserved keywords Purpose
childRecords Specifies the childRecords of a parentData
hasChildRecords Specifies whether the record contains child records
hasFilteredChildRecords Specifies whether the record contains filtered child records
expanded Specifies whether the child records are expanded
parentItem Specifies the parentItem of childRecords
index Specifies the index of current record
level Specifies the hierarchy level of record
filterLevel Specifies the hierarchy level of filtered record
parentIdMapping Specifies the parentID
uniqueID Specifies the unique ID of a record
parentUniqueID Specifies the parent Unique ID of a record
checkboxState Specifies the checkbox state of a record
isSummaryRow Specifies the summary of a record
taskData Specifies the main data
primaryParent Specifies the Primary data

Remote data

To bind remote data to TreeGrid component, assign service data as an instance of DataManager to the dataSource property. To interact with remote data source, provide the endpoint url and define the hasChildMapping property of treegrid.

The hasChildMapping property maps the field name in data source, that denotes whether current record holds any child records. This is useful internally to show expand icon while binding child data on demand.

The TreeGrid provides Load on Demand support for rendering remote data. The Load on demand is considered in TreeGrid for the following actions.

  • Expanding root nodes.
  • Navigating pages, with paging enabled in TreeGrid.

When load on demand is enabled, all the root nodes are rendered in collapsed state at initial load.

When load on demand support is enabled in TreeGrid with paging, the current or active page’s root node alone will be rendered in collapsed state. On expanding the root node, the child nodes will be loaded from the remote server.

When a root node is expanded, its child nodes are rendered and are cached locally, such that on consecutive expand/collapse actions on root node, the child nodes are loaded from the cache instead from the remote server.

Similarly, if the user navigates to a new page, the root nodes of that specific page, will be rendered with request to the remote server.

Remote Data Binding supports only Self-Referential Data and by default the pageSizeMode for Remote Data is Root mode. i.e only root node’s count will be shown in pager while using Remote Data

Source
Preview
index.ts
index.html
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import { TreeGrid, Page }from '@syncfusion/ej2-treegrid';
import { DataManager, WebApiAdaptor } from '@syncfusion/ej2-data';

let data: DataManager = new DataManager({
url: 'https://ej2services.syncfusion.com/production/web-services/api/SelfReferenceData',
adaptor: new WebApiAdaptor, crossDomain: true
});

TreeGrid.Inject(Page);
let treegrid: TreeGrid = new TreeGrid({
dataSource: data,
hasChildMapping : 'isParent',
idMapping: 'TaskID',
parentIdMapping: 'ParentItem',
height: 260,
allowPaging: true,
treeColumnIndex: 1,
    columns: [
    { field: 'TaskID', headerText: 'Task ID', textAlign: 'Right', width: 90 },
    { field: 'TaskName', headerText: 'Task Name', width: 180 },
    { field: 'StartDate', headerText: 'Start Date', textAlign: 'Right', width: 90, format: { skeleton: 'yMd', type: 'date' } },
    { field: 'Duration', headerText: 'Duration', width: 80, textAlign: 'Right' }
]
});
treegrid.appendTo('#TreeGrid');
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<!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="//cdn.syncfusion.com/ej2/ej2-base/styles/material.css" rel="stylesheet" />
    <link href="//cdn.syncfusion.com/ej2/ej2-grids/styles/material.css" rel="stylesheet" />
    <link href="//cdn.syncfusion.com/ej2/ej2-treegrid/styles/material.css" rel="stylesheet" />
    <link href="//cdn.syncfusion.com/ej2/ej2-buttons/styles/material.css" rel="stylesheet" />
    <link href="//cdn.syncfusion.com/ej2/ej2-popups/styles/material.css" rel="stylesheet" />
    <link href="//cdn.syncfusion.com/ej2/ej2-navigations/styles/material.css" rel="stylesheet" />
    <link href="//cdn.syncfusion.com/ej2/ej2-dropdowns/styles/material.css" rel="stylesheet" />
    <link href="//cdn.syncfusion.com/ej2/ej2-lists/styles/material.css" rel="stylesheet" />
    <link href="//cdn.syncfusion.com/ej2/ej2-inputs/styles/material.css" rel="stylesheet" />
    <link href="//cdn.syncfusion.com/ej2/ej2-calendars/styles/material.css" rel="stylesheet" />
    
    
    
    <link href="//cdn.syncfusion.com/ej2/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>
</head>
<body>
    <div id='loader'>Loading....</div>
    <div id='container'>
        <div id='TreeGrid'></div>        
    </div>
</body>
</html>

By default, DataManager uses ODataAdaptor for remote data-binding. Based on the RESTful web services, set the corresponding adaptor to DataManager. Refer here for more details. Filtering and searching server-side data operations are not supported in load on demand

LoadChildOnDemand

While binding remote data to Tree Grid component, by default Tree Grid renders parent rows in collapsed state. Tree Grid provides option to load the child records also during the initial rendering itself for remote data binding by setting loadChildOnDemand as true.

When loadChildOnDemand is enabled parent records are rendered in expanded state.

The following code example describes the behavior of the loadChildOnDemand feature of Tree Grid.

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import { TreeGrid, Page }from '@syncfusion/ej2-treegrid';
import { DataManager, UrlAdaptor } from '@syncfusion/ej2-data';

TreeGrid.Inject(Page);

let data: DataManager = new DataManager({
url: "Home/DataSource",
updateUrl: "Home/Update",
insertUrl: "Home/Insert",
removeUrl: "Home/Delete",
batchUrl: "Home/Remove",
adaptor: new UrlAdaptor
});


let treegrid: TreeGrid = new TreeGrid({
dataSource: data,
idMapping: 'TaskID',
parentIdMapping: 'ParentItem',
hasChildMapping: 'isParent',
loadChildOnDemand: true,
height: 260,
allowPaging: true,
treeColumnIndex: 1,
    columns: [
    { field: 'TaskID', headerText: 'Task ID', textAlign: 'Right', width: 90 },
    { field: 'TaskName', headerText: 'Task Name', width: 180 },
    { field: 'StartDate', headerText: 'Start Date', textAlign: 'Right', width: 90, format: { skeleton: 'yMd', type: 'date' } },
    { field: 'Duration', headerText: 'Duration', width: 80, textAlign: 'Right' }
]
});
treegrid.appendTo('#TreeGrid');

Also while using loadChildOnDemand we need to handle the child records on server end and it is applicable to CRUD operations also.

The following code example describes handling of child records at server end.

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public ActionResult UrlDatasource(DataManagerRequest dm)
{
if (TreeData.tree.Count == 0)
      TreeData.GetTree();
IEnumerable DataSource = TreeData.tree;

DataOperations operation = new DataOperations();
if (dm.Where != null && dm.Where.Count > 0)
{
    DataSource = operation.PerformFiltering(DataSource, dm.Where, "and");   //perform filtering  
}
if (dm.Sorted != null && dm.Sorted.Count > 0)
{
    DataSource = operation.PerformSorting(DataSource, dm.Sorted);  //perform sorting
}
var count = DataSource.ToList<TreeData>().Count();
if (dm.Skip != 0)
{
    DataSource = operation.PerformSkip(DataSource, dm.Skip);   //Paging
}
if (dm.Take != 0)
{
    DataSource = operation.PerformTake(DataSource, dm.Take);
}
if (dm.Where != null)
{
    DataSource = CollectChildRecords(DataSource, dm);  // method to collect child records
}

return dm.RequiresCounts ? Json(new { result = DataSource, count = count }) : Json(DataSource);
}

 public IEnumerable CollectChildRecords(IEnumerable datasource, DataManagerRequest dm)
 {
 DataOperations operation = new DataOperations();
 IEnumerable DataSource = TreeData.tree;  // use the total DataSource here
 string IdMapping = "TaskID";  // define your IdMapping field name here
 int[] TaskIds = new int[0];
 foreach (var rec in datasource)
 {
    int taskid = (int)rec.GetType().GetProperty(IdMapping).GetValue(rec);
    TaskIds = TaskIds.Concat(new int[] { taskid }).ToArray();     //get the Parentrecord Ids based on IdMapping Field  
 }
IEnumerable ChildRecords = null;
 foreach (int id in TaskIds)
 {
    dm.Where[0].value = id;
    IEnumerable records = operation.PerformFiltering(DataSource, dm.Where, dm.Where[0].Operator);     //perform filtering to collect the childrecords based on Ids
    ChildRecords = ChildRecords == null || (ChildRecords.AsQueryable().Count() == 0) ? records : ((IEnumerable<object>)ChildRecords).Concat((IEnumerable<object>)records);  //concate the childrecords with dataSource
 }
 if (ChildRecords != null)
 {
    ChildRecords = CollectChildRecords(ChildRecords, dm);  // repeat the operation for inner level child
    if (dm.Sorted != null && dm.Sorted.Count > 0) // perform Sorting
    {
        ChildRecords = operation.PerformSorting(ChildRecords, dm.Sorted);
    }
    datasource = ((IEnumerable<object>)datasource).Concat((IEnumerable<object>)ChildRecords);    //concate the childrecords with dataSource  
 }
return datasource;
 }

Offline Mode

On remote data binding, all treegrid actions such as paging, loading child on-demand, will be processed on server-side. To avoid postback, set the treegrid to load all data on initialization and make the actions process in client-side. To enable this behavior, use the offline property of DataManager.

Source
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index.ts
index.html
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import { TreeGrid, Page }from '@syncfusion/ej2-treegrid';
import { DataManager, WebApiAdaptor } from '@syncfusion/ej2-data';

let data: DataManager = new DataManager({
url: 'https://ej2services.syncfusion.com/production/web-services/api/SelfReferenceData',
adaptor: new WebApiAdaptor, crossDomain: true, offline: true
});

TreeGrid.Inject(Page);
let treegrid: TreeGrid = new TreeGrid({
dataSource: data,
idMapping: 'TaskID',
parentIdMapping: 'ParentItem',
height: 260,
allowPaging: true,
treeColumnIndex: 1,
    columns: [
    { field: 'TaskID', headerText: 'Task ID', textAlign: 'Right', width: 90 },
    { field: 'TaskName', headerText: 'Task Name', width: 180 },
    { field: 'StartDate', headerText: 'Start Date', textAlign: 'Right', width: 90, format: { skeleton: 'yMd', type: 'date' } },
    { field: 'Duration', headerText: 'Duration', width: 80, textAlign: 'Right' }
]
});
treegrid.appendTo('#TreeGrid');
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<!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="//cdn.syncfusion.com/ej2/ej2-base/styles/material.css" rel="stylesheet" />
    <link href="//cdn.syncfusion.com/ej2/ej2-grids/styles/material.css" rel="stylesheet" />
    <link href="//cdn.syncfusion.com/ej2/ej2-treegrid/styles/material.css" rel="stylesheet" />
    <link href="//cdn.syncfusion.com/ej2/ej2-buttons/styles/material.css" rel="stylesheet" />
    <link href="//cdn.syncfusion.com/ej2/ej2-popups/styles/material.css" rel="stylesheet" />
    <link href="//cdn.syncfusion.com/ej2/ej2-navigations/styles/material.css" rel="stylesheet" />
    <link href="//cdn.syncfusion.com/ej2/ej2-dropdowns/styles/material.css" rel="stylesheet" />
    <link href="//cdn.syncfusion.com/ej2/ej2-lists/styles/material.css" rel="stylesheet" />
    <link href="//cdn.syncfusion.com/ej2/ej2-inputs/styles/material.css" rel="stylesheet" />
    <link href="//cdn.syncfusion.com/ej2/ej2-calendars/styles/material.css" rel="stylesheet" />
    
    
    
    <link href="//cdn.syncfusion.com/ej2/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>
</head>
<body>
    <div id='loader'>Loading....</div>
    <div id='container'>
        <div id='TreeGrid'></div>        
    </div>
</body>
</html>

Custom Adaptor

You can create your own adaptor by extending the built-in adaptors. The following demonstrates custom adaptor approach and how to add a serial number for the records by overriding the built-in response processing using the processResponse method of the WebApiAdaptor.

Source
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index.ts
index.html
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import { TreeGrid } from '@syncfusion/ej2-treegrid';
import { DataManager, WebApiAdaptor } from '@syncfusion/ej2-data';

class SerialNoAdaptor extends WebApiAdaptor {
public processResponse(): Object[] {
    let i: number = 0;
    // calling base class processResponse function
    let original: Object[] = super.processResponse.apply(this, arguments);
    // adding serial number
    original.forEach((item: Object) => item['Sno'] = ++i);
    return original;
}
}

let data: DataManager = new DataManager({
url: 'https://ej2services.syncfusion.com/production/web-services/api/SelfReferenceData',
adaptor: new SerialNoAdaptor, crossDomain: true, offline: true
});

let treegrid: TreeGrid = new TreeGrid({
dataSource: data,
idMapping: 'TaskID',
parentIdMapping: 'ParentItem',
height: 260,
treeColumnIndex: 1,
    columns: [
    { field: 'Sno', width: 120, headerText: 'SNO', textAlign: 'Right' },
    { field: 'TaskName', headerText: 'Task Name', width: 180 },
    { field: 'StartDate', headerText: 'Start Date', textAlign: 'Right', width: 90, format: { skeleton: 'yMd', type: 'date' } },
    { field: 'Duration', headerText: 'Duration', width: 80, textAlign: 'Right' }
]
});
treegrid.appendTo('#TreeGrid');
Copied to clipboard
<!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="//cdn.syncfusion.com/ej2/ej2-base/styles/material.css" rel="stylesheet" />
    <link href="//cdn.syncfusion.com/ej2/ej2-grids/styles/material.css" rel="stylesheet" />
    <link href="//cdn.syncfusion.com/ej2/ej2-treegrid/styles/material.css" rel="stylesheet" />
    <link href="//cdn.syncfusion.com/ej2/ej2-buttons/styles/material.css" rel="stylesheet" />
    <link href="//cdn.syncfusion.com/ej2/ej2-popups/styles/material.css" rel="stylesheet" />
    <link href="//cdn.syncfusion.com/ej2/ej2-navigations/styles/material.css" rel="stylesheet" />
    <link href="//cdn.syncfusion.com/ej2/ej2-dropdowns/styles/material.css" rel="stylesheet" />
    <link href="//cdn.syncfusion.com/ej2/ej2-lists/styles/material.css" rel="stylesheet" />
    <link href="//cdn.syncfusion.com/ej2/ej2-inputs/styles/material.css" rel="stylesheet" />
    <link href="//cdn.syncfusion.com/ej2/ej2-calendars/styles/material.css" rel="stylesheet" />
    
    
    
    <link href="//cdn.syncfusion.com/ej2/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>
</head>
<body>
    <div id='loader'>Loading....</div>
    <div id='container'>
        <div id='TreeGrid'></div>        
    </div>
</body>
</html>

Sending additional parameters to the server

To add a custom parameter to the data request, use the addParams method of Query class. Assign the Query object with additional parameters to the treegrid query property.

Source
Preview
index.ts
index.html
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import { TreeGrid, Page } from '@syncfusion/ej2-treegrid';
import { DataManager, Query, WebApiAdaptor } from '@syncfusion/ej2-data';

let data: DataManager = new DataManager({
url: 'https://ej2services.syncfusion.com/production/web-services/api/SelfReferenceData',
adaptor: new WebApiAdaptor, crossDomain: true
});

TreeGrid.Inject(Page);
let treegrid: TreeGrid = new TreeGrid({
dataSource: data,
idMapping: 'TaskID',
parentIdMapping: 'ParentItem',
height: 260,
allowPaging: true,
query: new Query().addParams('ej2treegrid', 'true'),
treeColumnIndex: 1,
    columns: [
    { field: 'TaskID', headerText: 'Task ID', textAlign: 'Right', width: 90 },
    { field: 'TaskName', headerText: 'Task Name', width: 180 },
    { field: 'StartDate', headerText: 'Start Date', textAlign: 'Right', width: 90, format: { skeleton: 'yMd', type: 'date' } },
    { field: 'Duration', headerText: 'Duration', width: 80, textAlign: 'Right' }
]
});
treegrid.appendTo('#TreeGrid');
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<!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="//cdn.syncfusion.com/ej2/ej2-base/styles/material.css" rel="stylesheet" />
    <link href="//cdn.syncfusion.com/ej2/ej2-grids/styles/material.css" rel="stylesheet" />
    <link href="//cdn.syncfusion.com/ej2/ej2-treegrid/styles/material.css" rel="stylesheet" />
    <link href="//cdn.syncfusion.com/ej2/ej2-buttons/styles/material.css" rel="stylesheet" />
    <link href="//cdn.syncfusion.com/ej2/ej2-popups/styles/material.css" rel="stylesheet" />
    <link href="//cdn.syncfusion.com/ej2/ej2-navigations/styles/material.css" rel="stylesheet" />
    <link href="//cdn.syncfusion.com/ej2/ej2-dropdowns/styles/material.css" rel="stylesheet" />
    <link href="//cdn.syncfusion.com/ej2/ej2-lists/styles/material.css" rel="stylesheet" />
    <link href="//cdn.syncfusion.com/ej2/ej2-inputs/styles/material.css" rel="stylesheet" />
    <link href="//cdn.syncfusion.com/ej2/ej2-calendars/styles/material.css" rel="stylesheet" />
    
    
    
    <link href="//cdn.syncfusion.com/ej2/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>
</head>
<body>
    <div id='loader'>Loading....</div>
    <div id='container'>
        <div id='TreeGrid'></div>        
    </div>
</body>
</html>

Handling HTTP error

During server interaction from the treegrid, some server-side exceptions may occur, and you can acquire those error messages or exception details in client-side using the actionFailure event.

The argument passed to the actionFailure event contains the error details returned from the server.

Source
Preview
index.ts
index.html
Copied to clipboard
import { TreeGrid } from '@syncfusion/ej2-treegrid';
import { DataManager } from '@syncfusion/ej2-data';

let data: DataManager = new DataManager({
url: 'http://some.com/invalidUrl'
});

let treegrid: TreeGrid = new TreeGrid({
dataSource: data,
idMapping: 'TaskID',
parentIdMapping: 'ParentItem',
actionFailure: (e) => {
   let span: HTMLElement = document.createElement('span');
   treegrid.element.parentNode.insertBefore(span, treegrid.element);
   span.style.color = '#FF0000'
   span.innerHTML = 'Server exception: 404 Not found';
},
treeColumnIndex: 1,
    columns: [
    { field: 'TaskID', headerText: 'Task ID', textAlign: 'Right', width: 90 },
    { field: 'TaskName', headerText: 'Task Name', width: 180 },
    { field: 'StartDate', headerText: 'Start Date', textAlign: 'Right', width: 90, format: { skeleton: 'yMd', type: 'date' } },
    { field: 'Duration', headerText: 'Duration', width: 80, textAlign: 'Right' }
]
});
treegrid.appendTo('#TreeGrid');
Copied to clipboard
<!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="//cdn.syncfusion.com/ej2/ej2-base/styles/material.css" rel="stylesheet" />
    <link href="//cdn.syncfusion.com/ej2/ej2-grids/styles/material.css" rel="stylesheet" />
    <link href="//cdn.syncfusion.com/ej2/ej2-treegrid/styles/material.css" rel="stylesheet" />
    <link href="//cdn.syncfusion.com/ej2/ej2-buttons/styles/material.css" rel="stylesheet" />
    <link href="//cdn.syncfusion.com/ej2/ej2-popups/styles/material.css" rel="stylesheet" />
    <link href="//cdn.syncfusion.com/ej2/ej2-navigations/styles/material.css" rel="stylesheet" />
    <link href="//cdn.syncfusion.com/ej2/ej2-dropdowns/styles/material.css" rel="stylesheet" />
    <link href="//cdn.syncfusion.com/ej2/ej2-lists/styles/material.css" rel="stylesheet" />
    <link href="//cdn.syncfusion.com/ej2/ej2-inputs/styles/material.css" rel="stylesheet" />
    <link href="//cdn.syncfusion.com/ej2/ej2-calendars/styles/material.css" rel="stylesheet" />
    
    
    
    <link href="//cdn.syncfusion.com/ej2/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>
</head>
<body>
    <div id='loader'>Loading....</div>
    <div id='container'>
        <div id='TreeGrid'></div>        
    </div>
</body>
</html>

The actionFailure event will be triggered not only for the server errors, but also when there is an exception while processing the treegrid actions.

Binding with Ajax

You can use TreeGrid dataSource property to bind the data source to TreeGrid from external Ajax request. In the below code we have fetched the data source from the server with the help of Ajax request and provided that to dataSource property by using onSuccess event of the Ajax.

Source
Preview
index.ts
index.html
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import { TreeGrid, Page }from '@syncfusion/ej2-treegrid';
import { Ajax } from '@syncfusion/ej2-base';

TreeGrid.Inject(Page);
let treegrid: TreeGrid = new TreeGrid({
idMapping: 'TaskID',
parentIdMapping: 'ParentItem',
pageSettings: {pageSize: 7},
allowPaging: true,
treeColumnIndex: 1,
columns: [
    { field: 'TaskID', headerText: 'Task ID', textAlign: 'Right', width: 90 },
    { field: 'TaskName', headerText: 'Task Name', width: 180 },
    { field: 'Duration', headerText: 'Duration', width: 80, textAlign: 'Right' },
    { field: 'Progress', headerText: 'Progress', width: 80, textAlign: 'Right' }
]
});
treegrid.appendTo('#TreeGrid');

let button: HTMLElement = document.createElement('button');
button.textContent = 'Bind Data';
treegrid.element.parentNode.insertBefore(button, treegrid.element);
button.addEventListener("click", function(e){
let ajax = new Ajax("https://ej2services.syncfusion.com/production/web-services/api/SelfReferenceData","GET");
treegrid.showSpinner();
ajax.send();
ajax.onSuccess = function (data: string) {
    treegrid.hideSpinner();
    treegrid.dataSource = JSON.parse(data);
};
});
Copied to clipboard
<!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="//cdn.syncfusion.com/ej2/ej2-base/styles/material.css" rel="stylesheet" />
    <link href="//cdn.syncfusion.com/ej2/ej2-grids/styles/material.css" rel="stylesheet" />
    <link href="//cdn.syncfusion.com/ej2/ej2-treegrid/styles/material.css" rel="stylesheet" />
    <link href="//cdn.syncfusion.com/ej2/ej2-buttons/styles/material.css" rel="stylesheet" />
    <link href="//cdn.syncfusion.com/ej2/ej2-popups/styles/material.css" rel="stylesheet" />
    <link href="//cdn.syncfusion.com/ej2/ej2-navigations/styles/material.css" rel="stylesheet" />
    <link href="//cdn.syncfusion.com/ej2/ej2-dropdowns/styles/material.css" rel="stylesheet" />
    <link href="//cdn.syncfusion.com/ej2/ej2-lists/styles/material.css" rel="stylesheet" />
    <link href="//cdn.syncfusion.com/ej2/ej2-inputs/styles/material.css" rel="stylesheet" />
    <link href="//cdn.syncfusion.com/ej2/ej2-calendars/styles/material.css" rel="stylesheet" />
    
    
    
    <link href="//cdn.syncfusion.com/ej2/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>
</head>
<body>
    <div id='loader'>Loading....</div>
    <div id='container'>
        <div id='TreeGrid'></div>        
    </div>
</body>
</html>
  • If you bind the dataSource from this way, then it acts like a local dataSource. So you cannot perform any server side crud actions.

Custom Binding

It is possible to handle data processing externally and bind the result to the TreeGrid. This helps you to provide your own custom data logic. TreeGrid expects an object as the result of the custom logic and the emitted value should be an object with properties result and count.

In this context, we are going to use DataManager with WebApi Adaptor for handling remote interaction, you can choose any HTTP client as per your choice.

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import { TreeGrid, Page} from '../src';
import { DataManager, WebApiAdaptor, Query } from '@syncfusion/ej2-data';
import { isNullOrUndefined } from '@syncfusion/ej2-base';

TreeGrid.Inject(Page);

let data: DataManager = new DataManager({
url: 'http://localhost:51473/api/Tasks',    ////   url for fetching the data from server
adaptor: new WebApiAdaptor,
crossDomain: true
});

                    /////  filter query for fetching the root level records only  and  take             value should be equal to the pageSize value of pageSettings

data.executeQuery(new Query().where('ParentId', 'equal', null).take(3).skip(0).requiresCount()).then((e: any) => {

let treegrid: TreeGrid = new TreeGrid({
    dataSource: { result: e.result, count: e.count },
    hasChildMapping: 'IsParent',
    idMapping: 'TaskId',
    parentIdMapping: 'ParentId',
    allowPaging: true,
    pageSettings: { pageSize: 3, pageSizeMode: 'Root' },
    dataStateChange: function (state: any) {
        if (state.action.requestType === 'paging') {
            data.executeQuery(new Query().skip(state.skip).take(state.take).requiresCount()).then(function (e: any) {
                this.dataSource = { result: e.result, count: e.count };
            });
        }
    },
    treeColumnIndex: 1,
    columns: [
        { field: 'TaskId', headerText: 'Task ID', isPrimaryKey: true, textAlign: 'Right', width: 120 },
        { field: 'TaskName', headerText: 'Task Name', width: 150 },
        { field: 'StartDate', headerText: 'Start Date', textAlign: 'Right', width: 120, format: { skeleton: 'yMd', type: 'date' } },
        { field: 'Duration', headerText: 'Duration', width: 110, textAlign: 'Right' },
        { field: 'Progress', headerText: 'Progress', width: 110 },
    ]
});
treegrid.appendTo('#TreeGrid');
});

We have a limitation for Custom Binding feature of TreeGrid. This feature works only for Self Referential data binding with pageSizeMode as Root.

Handling Child Data

Using the custom binding feature you can bind the child data for a parent record as per your custom logic. When a parent record is expanded, dataStateChange event is triggered in which you can assign your custom data to the childData property of the dataStateChange event arguments. After assigning the child data, childDataBind method should be called from the dataStateChange event arguments to indicate that the data is bound.

In this context, initially we have assigned only the parent records to the treegrid dataSource and fetched the required child records in the dataStateChange event.

Copied to clipboard
import { TreeGrid, Page, Toolbar, Sort } from '../src';
import { DataManager, WebApiAdaptor, Query } from '@syncfusion/ej2-data';
import { isNullOrUndefined } from '@syncfusion/ej2-base';

TreeGrid.Inject(Page);

let data: DataManager = new DataManager({
url: 'http://localhost:51473/api/Tasks',     //// url for fetching the data from server
adaptor: new WebApiAdaptor,
crossDomain: true
});

        /// filter query for fetching only the root level records

data.executeQuery(new Query().where('ParentId', 'equal', null).take(3).skip(0).requiresCount()).then((e: any) => {

let treegrid: TreeGrid = new TreeGrid({
    dataSource: { result: e.result, count: e.count },
    hasChildMapping: 'IsParent',
    idMapping: 'TaskId',
    parentIdMapping: 'ParentId',
    allowPaging: true,
    pageSettings: { pageSize: 3, pageSizeMode: 'Root' },
    dataStateChange: function (state: any) {
        if (!isNullOrUndefined(state.requestType) && state.requestType === 'expand') {

            //// filter query for fetching the child records of the expanded record

            data.executeQuery(new Query().where('ParentId', 'equal', state.data.TaskId)).then(function (e: any) {
                state.childData = e.result;
                state.childDataBind();
            });
        } else {
            data.executeQuery(new Query().skip(state.skip).take(state.take).requiresCount()).then(function (e: any) {
                this.dataSource = { result: e.result, count: e.count };
            });
        }
    },
    treeColumnIndex: 1,
    columns: [
        { field: 'TaskId', headerText: 'Task ID', isPrimaryKey: true, textAlign: 'Right', width: 120 },
        { field: 'TaskName', headerText: 'Task Name', width: 150 },
        { field: 'StartDate', headerText: 'Start Date', textAlign: 'Right', width: 120, format: { skeleton: 'yMd', type: 'date' } },
        { field: 'Duration', headerText: 'Duration', width: 110, textAlign: 'Right' },
        { field: 'Progress', headerText: 'Progress', width: 110 },
    ]
});
treegrid.appendTo('#TreeGrid');
});

Handling TreeGrid Actions

For TreeGrid actions such as paging, sorting, etc dataStateChange event will be invoked. You have to query and resolve data using Ajax in this event based on the state arguments.

Copied to clipboard
import { TreeGrid, Page, Toolbar, Sort } from '../src';
import { DataManager, WebApiAdaptor, Query } from '@syncfusion/ej2-data';
import { isNullOrUndefined } from '@syncfusion/ej2-base';

TreeGrid.Inject(Page);

let data: DataManager = new DataManager({
url: 'http://localhost:51473/api/Tasks',     //// url for fetching the data from server
adaptor: new WebApiAdaptor,
crossDomain: true
});

        /// filter query for fetching only the root level records

data.executeQuery(new Query().where('ParentId', 'equal', null).take(3).skip(0).requiresCount()).then((e: any) => {

let treegrid: TreeGrid = new TreeGrid({
    dataSource: { result: e.result, count: e.count },
    hasChildMapping: 'IsParent',
    idMapping: 'TaskId',
    parentIdMapping: 'ParentId',
    allowPaging: true,
    allowSorting: true,
    pageSettings: { pageSize: 3, pageSizeMode: 'Root' },
    dataStateChange: function (state: any) {
        if (!isNullOrUndefined(state.requestType) && state.requestType === 'expand') {

                         //// filter query for fetching the child records of the expanded record

            data.executeQuery(new Query().where('ParentId', 'equal', state.data.TaskId)).then(function (e: any) {
                state.childData = e.result;
                state.childDataBind();
            });
        }
        if (state.action.requestType === 'paging') {
            data.executeQuery(new Query().skip(state.skip).take(state.take).requiresCount()).then(function (e: any) {
                this.dataSource = { result: e.result, count: e.count };
            });
        }
        if (state.action.requestType === 'sorting') {

                //// sort query for getting the sorted records from server

            data.executeQuery(new Query().sortBy('TaskId', 'descending').addParams('IdMapping','TaskId').skip(state.skip).take(state.take).requiresCount()).then(function (e: any) {
                    this.dataSource = { result: e.result, count: e.count };
            });
        }
    },
    treeColumnIndex: 1,
    columns: [
        { field: 'TaskId', headerText: 'Task ID', isPrimaryKey: true, textAlign: 'Right', width: 120 },
        { field: 'TaskName', headerText: 'Task Name', width: 150 },
        { field: 'StartDate', headerText: 'Start Date', textAlign: 'Right', width: 120, format: { skeleton: 'yMd', type: 'date' } },
        { field: 'Duration', headerText: 'Duration', width: 110, textAlign: 'Right' },
        { field: 'Progress', headerText: 'Progress', width: 110 },
    ]
});
treegrid.appendTo('#TreeGrid');
});

Performing CRUD Actions

The dataSourceChanged event will be triggered for updating the treegrid data. You can perform the save operation based on the event arguments and call the endEdit method to indicate the completion of save operation.

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import { TreeGrid, Page, Toolbar, Sort, Filter, Edit } from '../src';
import { DataManager, WebApiAdaptor, Query } from '@syncfusion/ej2-data';
import { isNullOrUndefined } from '@syncfusion/ej2-base';

TreeGrid.Inject(Page, Toolbar, Sort, Filter, Edit);

let data: DataManager = new DataManager({
url: 'http://localhost:51473/api/Tasks',
adaptor: new WebApiAdaptor,
crossDomain: true
});

data.executeQuery(new Query().where('ParentId', 'equal', null).take(3).skip(0).requiresCount()).then((e: any) => {

let treegrid: TreeGrid = new TreeGrid({
    dataSource: { result: e.result, count: e.count },
    hasChildMapping: 'IsParent',
    idMapping: 'TaskId',
    parentIdMapping: 'ParentId',
    allowPaging: true,
    toolbar: ['Add', 'Edit', 'Delete', 'Update', 'Cancel'],
    editSettings: { allowEditing: true, allowAdding: true, allowDeleting: true, mode: 'Row' },
    pageSettings: { pageSize: 3, pageSizeMode: 'Root' },
    dataSourceChanged: function (state: any) {
        if (state.action == 'add') {
            state.endEdit();
        }
        else if (state.action == 'edit') {
            state.endEdit();
        }
        else if (state.requestType == 'delete') {
            state.endEdit();
        }
    },
    dataStateChange: function (state: any) {
        if (!isNullOrUndefined(state.requestType) && state.requestType === 'expand') {
            data.executeQuery(new Query().where('ParentId', 'equal', state.data.TaskId)).then(function (e: any) {
                state.childData = e.result;
                state.childDataBind();
            });
        } else {
            data.executeQuery(new Query().where('ParentId', 'equal', null).take(3).skip(0).requiresCount()).then(function (e: any) {
                this.dataSource = { result: e.result, count: e.count };
            });
        }
    },
    treeColumnIndex: 1,
    columns: [
        { field: 'TaskId', headerText: 'Task ID', isPrimaryKey: true, textAlign: 'Right', width: 120 },
        { field: 'TaskName', headerText: 'Task Name', width: 150 },
        { field: 'StartDate', headerText: 'Start Date', textAlign: 'Right', width: 120, format: { skeleton: 'yMd', type: 'date' } },
        { field: 'Duration', headerText: 'Duration', width: 110, textAlign: 'Right' },
        { field: 'Progress', headerText: 'Progress', width: 110 },
    ]
});
treegrid.appendTo('#TreeGrid');
});

Calculate aggregates

The footer aggregate values should be calculated and sent along with the dataSource property as follows. The aggregate property of the data source should contain the aggregate value assigned to the property named in the field – type format. For example, the Sum aggregate value for the Duration field should be assigned to the property named as Duration - sum.

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{
result: [{..}, {..}, {..}, ...],
count: 830,
aggregates: { 'Freight - sum' : 450,'EmployeeID - min': 1 }
}

Provide Excel Filter data source

The dataStateChange event will be triggered with appropriate arguments when the excel filter requests the filter choice data source. You need to resolve the excel filter data source using the dataSource resolver function from the state argument as follows.

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import { TreeGrid, Page, Filter} from '../src';
import { DataManager, WebApiAdaptor, Query } from '@syncfusion/ej2-data';
import { isNullOrUndefined } from '@syncfusion/ej2-base';

TreeGrid.Inject(Page, Filter);

let data: DataManager = new DataManager({
url: 'http://localhost:51473/api/Tasks',    ////   url for fetching the data from server
adaptor: new WebApiAdaptor,
crossDomain: true
});

        ///// filter query for fetching the root level records only

data.executeQuery(new Query().where('ParentId', 'equal', null).take(3).skip(0).requiresCount()).then((e: any) => {

let treegrid: TreeGrid = new TreeGrid({
    dataSource: { result: e.result, count: e.count },
    hasChildMapping: 'IsParent',
    idMapping: 'TaskId',
    parentIdMapping: 'ParentId',
    allowPaging: true,
    allowFiltering: true,
    filterSettings: { type: 'Excel' },
    pageSettings: { pageSize: 3, pageSizeMode: 'Root' },
    dataStateChange: function (state: any) {
        if (state.action && (state.action.requestType === 'filterchoicerequest'
            || state.action.requestType ==='filtersearchbegin')) {
            data.executeQuery(new Query().skip(state.skip).take(state.take).requiresCount()).then(function (e: any) {
                state.dataSource && state.dataSource(e);  /// resolve the excel filter dataSource
            });
        }
        else {
            /// take value must be always be equal to the pageSize value of pageSetings
            data.executeQuery(new Query().skip(state.skip).take(state.take).requiresCount()).then(function (e: any) {
                this.dataSource = { result: e.result, count: e.count };
            });
        }
    },
    treeColumnIndex: 1,
    columns: [
        { field: 'TaskId', headerText: 'Task ID', isPrimaryKey: true, textAlign: 'Right', width: 120 },
        { field: 'TaskName', headerText: 'Task Name', width: 150 },
        { field: 'StartDate', headerText: 'Start Date', textAlign: 'Right', width: 120, format: { skeleton: 'yMd', type: 'date' } },
        { field: 'Duration', headerText: 'Duration', width: 110, textAlign: 'Right' },
        { field: 'Progress', headerText: 'Progress', width: 110 },
    ]
});
treegrid.appendTo('#TreeGrid');
});