Angular TreeView API

The TreeView widget is a tree-like representation of textual data.

import { DxTreeViewModule } from "devextreme-angular"

DevExtreme widgets are integrated with many popular libraries and frameworks. See the Installation section (for JavaScript libraries) or the Prerequisites and Installation section (for ASP.NET MVC framework) to find details on setting up DevExtreme with a particular library or framework.

The following code shows how to create the TreeView widget using every supported library and framework. For more details on working with widgets in these libraries and frameworks, see the Widget Basics topic for jQuery, Angular, AngularJS, Knockout or ASP.NET MVC.

jQuery

JavaScript

HTML

$(function () {
    $("#treeView").dxTreeView({
        dataSource: [
            { id: "1", text: "Item 1" },
            { id: "1_1", text: "Subitem 1.1", parentId: "1" },
            { id: "1_2", text: "Subitem 1.2", parentId: "1" },
            { id: "2", text: "Item 2" },
            { id: "2_1", text: "Subitem 2.1", parentId: "2" },
            { id: "2_2", text: "Subitem 2.2", parentId: "2" }
        ],
        dataStructure: 'plain'
    });
});

<div id="treeView"></div>

Angular

HTML

TypeScript

<dx-tree-view
    [dataSource]="treeViewDataSource"
    dataStructure="plain">
</dx-tree-view>

import { DxTreeViewModule } from 'devextreme-angular'
// ...
export class AppComponent {
    treeViewDataSource = [
        { id: "1", text: "Item 1" },
        { id: "1_1", text: "Subitem 1.1", parentId: "1" },
        { id: "1_2", text: "Subitem 1.2", parentId: "1" },
        { id: "2", text: "Item 2" },
        { id: "2_1", text: "Subitem 2.1", parentId: "2" },
        { id: "2_2", text: "Subitem 2.2", parentId: "2" }
    ];
}
@NgModule({
    imports: [
        // ...
        DxTreeViewModule
    ],
    // ...
})

AngularJS

HTML

JavaScript

<div ng-controller="DemoController">
    <div dx-tree-view="{
        dataSource: treeViewDataSource,
        dataStructure: 'plain'
    }"></div>
</div>

angular.module('DemoApp', ['dx'])
    .controller("DemoController", function ($scope) {
        $scope.treeViewDataSource = [
            { id: "1", text: "Item 1" },
            { id: "1_1", text: "Subitem 1.1", parentId: "1" },
            { id: "1_2", text: "Subitem 1.2", parentId: "1" },
            { id: "2", text: "Item 2" },
            { id: "2_1", text: "Subitem 2.1", parentId: "2" },
            { id: "2_2", text: "Subitem 2.2", parentId: "2" }
        ];
    });

Knockout

HTML

JavaScript

<div data-bind="dxTreeView: {
    dataSource: treeViewDataSource,
    dataStructure: 'plain'
}"></div>

var viewModel = {
    treeViewDataSource: [
        { id: "1", text: "Item 1" },
        { id: "1_1", text: "Subitem 1.1", parentId: "1" },
        { id: "1_2", text: "Subitem 1.2", parentId: "1" },
        { id: "2", text: "Item 2" },
        { id: "2_1", text: "Subitem 2.1", parentId: "2" },
        { id: "2_2", text: "Subitem 2.2", parentId: "2" }
    ]
};
ko.applyBindings(viewModel);

ASP.NET MVC Controls

Razor C#

Razor VB

@(Html.DevExtreme().TreeView()
    .ID("treeView")
    .DataSource(new object[] {
        new { id = "1", text = "Item 1" },
        new { id = "1_1", text = "Subitem 1.1", parentId = "1" },
        new { id = "1_2", text = "Subitem 1.2", parentId = "1" },
        new { id = "2", text = "Item 2" },
        new { id = "2_1", text = "Subitem 2.1", parentId = "2" },
        new { id = "2_2", text = "Subitem 2.2", parentId = "2" }
    })
    .DataStructure(TreeViewDataStructure.Plain)
)

@(Html.DevExtreme().TreeView() _
    .ID("treeView") _
    .DataSource({
        New With { .id = "1", .text = "Item 1" },
        New With { .id = "1_1", .text = "Subitem 1.1", .parentId = "1" },
        New With { .id = "1_2", .text = "Subitem 1.2", .parentId = "1" },
        New With { .id = "2", .text = "Item 2" },
        New With { .id = "2_1", .text = "Subitem 2.1", .parentId = "1" },
        New With { .id = "2_2", .text = "Subitem 2.2", .parentId = "1" }
    }) _
    .DataStructure(TreeViewDataStructure.Plain)
)

NOTE

The TreeView widget requires each data source item to contain at least a key field. Thus, the widget does not support data sources consisting of value items.

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Configuration

An object defining configuration options for the TreeView widget.

Name	Description
accessKey	Specifies the shortcut key that sets focus on the widget.
activeStateEnabled	Specifies whether or not the widget changes its state when interacting with a user.
animationEnabled	Specifies whether or not to animate item collapsing and expanding.
createChildren	Allows you to load nodes manually.
dataSource	A data source used to fetch data to be displayed by the widget.
dataStructure	Specifies whether a nested or plain array is used as a data source.
disabled	Specifies whether the widget responds to user interaction.
disabledExpr	Specifies the name of the data source item field whose value defines whether or not the corresponding widget item is disabled.
displayExpr	Specifies the name of the data source item field whose value is displayed by the widget.
elementAttr	Specifies the attributes to be attached to the widget's root element.
expandAllEnabled	Specifies whether or not a user can expand all tree view items by the "*" hot key.
expandedExpr	Specifies the name of the data source item field whose value defines whether or not the corresponding widget item is displayed expanded.
expandNodesRecursive	Specifies whether or not all parent nodes of an initially expanded node are displayed expanded.
focusStateEnabled	Specifies whether the widget can be focused using keyboard navigation.
hasItemsExpr	Specifies the name of the data source item field whose value defines whether or not the corresponding node includes child nodes.
height	Specifies the widget's height.
hint	Specifies text for a hint that appears when a user pauses on the widget.
hoverStateEnabled	Specifies whether the widget changes its state when a user pauses on it.
itemHoldTimeout	The time period in milliseconds before the onItemHold event is raised.
items	An array of items displayed by the widget.
itemsExpr	Specifies which data field contains nested items. Applies only if the dataStructure option is "tree".
itemTemplate	Specifies a custom template for items.
keyExpr	Specifies which data field provides keys for TreeView items.
noDataText	The text or HTML markup displayed by the widget if the item collection is empty.
onContentReady	A handler for the contentReady event. Executed when the widget's content is ready. This handler may be executed multiple times during the widget's lifetime depending on the number of times its content changes.
onDisposing	A handler for the disposing event. Executed when the widget is removed from the DOM using the remove(), empty(), or html() jQuery methods only.
onInitialized	A handler for the initialized event. Executed only once, after the widget is initialized.
onItemClick	A handler for the itemClick event.
onItemCollapsed	A handler for the itemCollapsed event.
onItemContextMenu	A handler for the itemContextMenu event.
onItemExpanded	A handler for the itemExpanded event.
onItemHold	A handler for the itemHold event.
onItemRendered	A handler for the itemRendered event.
onItemSelectionChanged	A handler for the itemSelectionChanged event.
onOptionChanged	A handler for the optionChanged event. Executed after an option of the widget is changed.
onSelectAllValueChanged	A function that is executed after the "Select All" check box's state changes. Applies only if showCheckBoxesMode is "selectAll" and selectionMode is "multiple".
onSelectionChanged	A handler for the selectionChanged event. Executed after selecting an item or clearing its selection.
parentIdExpr	Specifies the name of the data source item field for holding the parent key of the corresponding node.
rootValue	Specifies the parent ID value of the root item.
rtlEnabled	Switches the widget to a right-to-left representation.
scrollDirection	A string value specifying available scrolling directions.
searchEditorOptions	Configures the search panel.
searchEnabled	Specifies whether the search panel is visible.
searchExpr	Specifies a data object's field name or an expression whose value is compared to the search string.
searchMode	Specifies whether the widget finds entries that contain your search string or entries that only start with it.
searchTimeout	Specifies a delay in milliseconds between when a user finishes typing, and the search is executed.
searchValue	Specifies the current search string.
selectAllText	Specifies the text displayed at the "Select All" check box.
selectByClick	Specifies whether or not an item becomes selected if a user clicks it.
selectedExpr	Specifies the name of the data source item field whose value defines whether or not the corresponding widget items is selected.
selectionMode	Specifies item selection mode.
selectNodesRecursive	Specifies whether or not to select nodes recursively.
showCheckBoxesMode	Specifies the current check boxes display mode.
tabIndex	Specifies the number of the element when the Tab key is used for navigating.
virtualModeEnabled	Specifies if the virtual mode is enabled.
visible	Specifies whether the widget is visible.
width	Specifies the widget's width.

Methods

This section describes members used to manipulate the widget.

Name	Description
beginUpdate()	Prevents the widget from refreshing until the endUpdate() method is called.
collapseItem(itemData)	Collapses an item with a specific key.
collapseItem(itemElement)	Collapses an item found using its DOM node.
collapseItem(key)	Collapses an item with a specific key.
defaultOptions(rule)	Specifies the device-dependent default configuration options for this component.
dispose()	Disposes of all the resources allocated to the TreeView instance.
element()	Gets the root widget element.
endUpdate()	Refreshes the widget after a call of the beginUpdate() method.
expandItem(itemData)	Expands an item found using its data object.
expandItem(itemElement)	Expands an item found using its DOM node.
expandItem(key)	Expands an item with a specific key.
focus()	Sets focus on the widget.
getDataSource()	Gets the DataSource instance.
getInstance(element)	Gets the instance of a widget found using its DOM node.
getNodes()	Gets all nodes.
instance()	Gets the widget's instance. Use it to access other methods of the widget.
off(eventName)	Detaches all event handlers from a single event.
off(eventName, eventHandler)	Detaches a particular event handler from a single event.
on(eventName, eventHandler)	Subscribes to an event.
on(events)	Subscribes to events.
option()	Gets all widget options.
option(optionName)	Gets the value of a single option.
option(optionName, optionValue)	Updates the value of a single option.
option(options)	Updates the values of several options.
registerKeyHandler(key, handler)	Registers a handler to be executed when a user presses a specific key.
repaint()	Repaints the widget. Call it if you made modifications that changed the widget's state to invalid.
selectAll()	Selects all items.
selectItem(itemData)	Selects an item found using its data object.
selectItem(itemElement)	Selects an item found using its DOM node.
selectItem(key)	Selects an item with a specific key.
unselectAll()	Cancels the selection of all items.
unselectItem(itemData)	Cancels the selection of an item found using its data object.
unselectItem(itemElement)	Cancels the selection of an item found using its DOM node.
unselectItem(key)	Cancels the selection of an item with a specific key.
updateDimensions()	Updates the tree view scrollbars according to the current size of the widget content.

Events

This section describes events fired by this widget.

Name	Description
contentReady	Raised when the widget's content is ready.
disposing	Raised when the widget is removed from the DOM using the remove(), empty(), or html() jQuery methods only.
initialized	Raised only once, after the widget is initialized.
itemClick	Fires when a widget item is clicked.
itemCollapsed	Fires when a tree view item is collapsed.
itemContextMenu	Fires when the right mouse button is clicked when the pointer is over a widget item, or when the "sustained" (also known as a long press) touch action is performed.
itemExpanded	Fires when a tree view item is expanded.
itemHold	Fires when the widget's collection item is being held for the time period specified by the itemHoldTimeout option.
itemRendered	Fires after a collection item is rendered.
itemSelectionChanged	Fires when a tree view item is selected.
optionChanged	Raised after a widget option is changed.
selectAllValueChanged	Raised after the "Select All" check box's state changes.
selectionChanged	Raised after selecting an item or clearing its selection.

Node

A TreeView node.

Type:

Object

This section describes the contents of a TreeView node object. Such objects can be accessed using the getNodes() method and within functions handling the events whose name begins with item....

Default Item Template

This section lists the data source fields that are used in a default item template.

Type:

Object

By default, a predefined item template is applied to display the items of this widget. This template is based on certain fields of the data source provided for this widget. Below is the list of these fields. If the default item template is not appropriate for your task, implement a custom item template based on these or other fields of your data source.

Angular TreeView API

jQuery

Angular

AngularJS

Knockout

ASP.NET MVC Controls

See Also

Configuration

Methods

Events

See Also

Node

See Also

Default Item Template

See Also