Components / TreeView / API / TreeViewComponent / 
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TreeViewComponent

Represents the Kendo UI TreeView component for Angular.

Example
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Selector

kendo-treeview

Export Name

Accessible in templates as #kendoTreeViewInstance="kendoTreeView"

Inputs

NameTypeDefaultDescription

animate

boolean

Determines whether the content animation is enabled.

children

(item: object) => Observable<object[]>

A function which provides the child nodes for a given parent node (see example).

disableParentNodesOnly

boolean

false

Indicates whether only parent nodes should be disabled or their child nodes as well

expandDisabledNodes

boolean

false

Determines whether to allow expanding disabled nodes.

filter

string

Sets an initial value of the built-in input element used for filtering.

filterable

boolean

Renders the built-in input element for filtering the TreeView. If set to true, the component emits the filterChange event, which can be used to filter the TreeView manually. A built-in filtering implementation is available to use with the kendoTreeViewHierarchyBinding and kendoTreeViewFlatDataBinding directives.

filterInputPlaceholder

string

The hint which is displayed when the component is empty.

hasChildren

(item: object) => boolean

A function which determines if a specific node has child nodes (see example).

isChecked

(item: object, index: string) => CheckedState

A function which determines if a specific node is checked (see example).

isDisabled

(item: object, index: string) => boolean

A function which determines if a specific node is disabled.

isExpanded

(item: object, index: string) => boolean

A function which determines if a specific node is expanded.

isSelected

(item: object, index: string) => boolean

A function which determines if a specific node is selected (see example).

isVisible

(item: object, index: string) => boolean

A callback which determines whether a TreeView node should be rendered as hidden. The utility .k-hidden class is used to hide the nodes. Useful for custom filtering implementations.

loadOnDemand

boolean

true

Indicates whether the child nodes will be fetched on node expand or will be initially prefetched.

navigable

boolean

Determines whether the TreeView keyboard navigable is enabled.

nodes

any[]

The nodes which will be displayed by the TreeView (see example).

size

TreeViewSize

Sets the size of the component.

The possible values are:

  • small
  • medium (default)
  • large
  • none

textField

string | string[]

The fields of the data item that provide the text content of the nodes (see example). If the textField input is set to an array, each hierarchical level uses the field that corresponds to the same index in the array, or the last item in the array.

trackBy

TrackByFunction<object>

A function that defines how to track node changes. By default, the TreeView tracks the nodes by data item object reference.

 @Component({
     selector: 'my-app',
     template: `
         <kendo-treeview
             [nodes]="data"
             textField="text"
             [trackBy]="trackBy"
         >
         </kendo-treeview>
     `
 })
 export class AppComponent {
     public data: any[] = [
         { text: "Furniture" },
         { text: "Decor" }
     ];

     public trackBy(index: number, item: any): any {
         return item.text;
     }
 }

Events

NameTypeDescription

addItem

EventEmitter<TreeItemAddRemoveArgs>

Fires after a dragged item is dropped (see example). Called on the TreeView where the item is dropped.

checkedChange

EventEmitter<TreeItemLookup>

Fires when the user selects a TreeView node checkbox (see example).

childrenLoaded

EventEmitter<{ children: TreeItem[]; item: TreeItem; }>

Fires when the children of the expanded node are loaded.

collapse

EventEmitter<TreeItem>

Fires when the user collapses a TreeView node.

expand

EventEmitter<TreeItem>

Fires when the user expands a TreeView node.

filterChange

EventEmitter<string>

Fires when the value of the built-in filter input element changes.

filterStateChange

EventEmitter<FilterState>

Emits when the built-in filtering mechanism in the data-binding directives updates the node's visibility. Used for the built-in auto-expand functionalities of the component and available for custom implementations.

nodeClick

EventEmitter<NodeClickEvent>

Fires when the user clicks a TreeView node.

nodeDblClick

EventEmitter<NodeClickEvent>

Fires when the user double clicks a TreeView node.

nodeDrag

EventEmitter<TreeItemDragEvent>

Fires when an item is being dragged (see example).

nodeDragEnd

EventEmitter<TreeItemDragEvent>

Fires on the source TreeView after the dragged item has been dropped (see example).

nodeDragStart

EventEmitter<TreeItemDragStartEvent>

Fires just before the dragging of the node starts (see example). This event is preventable. If you prevent the event default, no drag hint will be created and the subsequent drag-related events will not be fired.

nodeDrop

EventEmitter<TreeItemDropEvent>

Fires on the target TreeView when a dragged item is dropped (see example). This event is preventable. If you prevent the event default (event.preventDefualt()) or invalidate its state (event.setValid(false)), the addItem and removeItem events will not be triggered.

Both operations cancel the default drop operation, but the indication to the user is different. event.setValid(false) indicates that the operation was unsuccessful by animating the drag clue to its original position. event.preventDefault() simply removes the clue, as if it has been dropped successfully. As a general rule, use preventDefault to manually handle the add and remove operations, and setValid(false) to indicate the operation was unsuccessful.

blur

EventEmitter<any>

Fires when the user blurs the component.

focus

EventEmitter<any>

Fires when the user focuses the component.

removeItem

EventEmitter<TreeItemAddRemoveArgs>

Fires after a dragged item is dropped (see example). Called on the TreeView from where the item is dragged.

selectionChange

EventEmitter<TreeItem>

Fires when the user selects a TreeView node (see example).

Methods

blur

Blurs the focused TreeView item.

collapseNode

Triggers the collapse event for the provided node.

Parameters

item

any

index

string

expandNode

Triggers the expand event for the provided node and displays it's loading indicator.

Parameters

item

any

index

string

focus

Focuses the first focusable item in the TreeView component if no hierarchical index is provided.

import { Component } from '@angular/core';

 @Component({
     selector: 'my-app',
     template: `
     <button (click)="treeview.focus('1')">Focuses the second node</button>
     <kendo-treeview
         #treeview
         [nodes]="data"
         textField="text"
     >
     </kendo-treeview>
 `
 })
 export class AppComponent {
     public data: any[] = [
         { text: "Furniture" },
         { text: "Decor" }
     ];
 }
Parameters

index?

string

getNodePageSize

Gets the current page size of the checked data item children collection (see example).

Since the root nodes collection is not associated with any parent data item, pass null as dataItem param to get its page size.

Parameters

dataItem

any

The parent data item of the targeted collection.

Returns

number
  • The page size of the checked data item children collection.

itemLookup

Based on the specified index, returns the TreeItemLookup node.

Parameters

index

string

The index of the node.

Returns

TreeItemLookup
  • The item that was searched (looked up).

rebindChildren

Triggers the children function for every expanded node, causing all rendered child nodes to be fetched again.

setNodePageSize

Sets the page size of the targeted data item children collection (see example).

Since the root nodes collection is not associated with any parent data item, pass null as dataItem param to target its page size.

Parameters

dataItem

any

The parent data item of the targeted collection.

pageSize

number

The new page size.

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