Angular TreeView Methods
This section describes members used to manipulate the widget.
beginUpdate()
Prevents the widget from refreshing until the endUpdate() method is called.
The beginUpdate() and endUpdate() methods prevent the widget from excessive updates when you are changing multiple widget settings at once. After the beginUpdate() method is called, the widget does not update its UI until the endUpdate() method is called.
See Also
collapseItem(itemElement)
Collapses an item found using its DOM node.
The item's DOM node.
See Also
defaultOptions(rule)
Specifies the device-dependent default configuration options for this component.
The component's default device options.
defaultOptions is a static method that the widget class supports. The following code demonstrates how to specify default options for all instances of the TreeView widget in an application executed on the desktop.
jQuery
DevExpress.ui.dxTreeView.defaultOptions({ device: { deviceType: "desktop" }, options: { // Here go the TreeView options } });
Angular
import TreeView from "devextreme/ui/tree_view"; // ... export class AppComponent { constructor () { TreeView.defaultOptions({ device: { deviceType: "desktop" }, options: { // Here go the TreeView options } }); } }
dispose()
Disposes of all the resources allocated to the TreeView instance.
The following code disposes of an TreeView instance that corresponds to the element ID (or reference variable in Angular) and removes the element from the DOM:
jQuery
$("#myTreeView").dxTreeView("dispose"); $("#myTreeView").remove();
Angular
<dx-tree-view #treeViewVar id="myTreeView"></dx-tree-view>
import { ..., ViewChild } from "@angular/core"; import { DxTreeViewComponent } from "devextreme-angular"; // ... export class AppComponent { @ViewChild("treeViewVar") treeView: DxTreeViewComponent; removeTreeView (e) { this.treeView.instance.dispose(); document.getElementById("myTreeView").remove(); } }
element()
Gets the root widget element.
An HTML element or a jQuery element when you use jQuery.
endUpdate()
Refreshes the widget after a call of the beginUpdate() method.
Main article: beginUpdate()
See Also
expandAll()
Expands all items. If you load items on demand, this method expands only the loaded items.
expandItem(itemData)
Expands an item found using its data object.
The item's data object.
expandItem(itemElement)
Expands an item found using its DOM node.
The item's DOM node.
See Also
getInstance(element)
Gets the instance of a widget found using its DOM node.
The widget's instance.
getInstance is a static method that the widget class supports. The following code demonstrates how to get the TreeView instance found in an element with the myTreeView
ID:
// Modular approach import TreeView from "devextreme/ui/tree_view"; ... let element = document.getElementById("myTreeView"); let instance = TreeView.getInstance(element) as TreeView; // Non-modular approach let element = document.getElementById("myTreeView"); let instance = DevExpress.ui.dxTreeView.getInstance(element);
See Also
getNodes()
Gets all nodes.
All nodes. Their structure is described in the Node section.
instance()
Gets the widget's instance. Use it to access other methods of the widget.
This widget's instance.
off(eventName)
Detaches all event handlers from a single event.
The event's name.
The object for which this method is called.
off(eventName, eventHandler)
Detaches a particular event handler from a single event.
The object for which this method is called.
on(eventName, eventHandler)
Subscribes to an event.
The object for which this method is called.
on(events)
Subscribes to events.
Events with their handlers: { "eventName1": handler1, "eventName2": handler2, ...}
The object for which this method is called.
option()
Gets all widget options.
The widget's options.
See Also
- Get and Set Options
- Call Methods: jQuery | Angular | AngularJS | Knockout | Vue | React | ASP.NET MVC
option(optionName)
Gets the value of a single option.
The option's name or full path.
This option's value.
See Also
- Get and Set Options
- Call Methods: jQuery | Angular | AngularJS | Knockout | Vue | React | ASP.NET MVC
option(optionName, optionValue)
Updates the value of a single option.
See Also
- Get and Set Options
- Call Methods: jQuery | Angular | AngularJS | Knockout | Vue | React | ASP.NET MVC
option(options)
Updates the values of several options.
Options with their new values.
See Also
- Get and Set Options
- Call Methods: jQuery | Angular | AngularJS | Knockout | Vue | React | ASP.NET MVC
registerKeyHandler(key, handler)
Registers a handler to be executed when a user presses a specific key.
A key.
A handler. Accepts the keydown event as the argument. It is a dxEvent or a jQuery.Event when you use jQuery.
The key argument accepts one of the following values:
- "backspace"
- "tab"
- "enter"
- "escape"
- "pageUp"
- "pageDown"
- "end"
- "home"
- "leftArrow"
- "upArrow"
- "rightArrow"
- "downArrow"
- "del"
- "space"
- "F"
- "A"
- "asterisk"
- "minus"
A custom handler for a key cancels the default handler for this key.
See Also
selectItem(itemData)
Selects an item found using its data object.
The item's data object.
See Also
selectItem(itemElement)
Selects an item found using its DOM node.
The item's DOM node.
See Also
unselectItem(itemData)
Cancels the selection of an item found using its data object.
The item's data object.
See Also
unselectItem(itemElement)
Cancels the selection of an item found using its DOM node.
The item's DOM node.
See Also
unselectItem(key)
Cancels the selection of an item with a specific key.
The item's key.
See Also
updateDimensions()
Updates the tree view scrollbars according to the current size of the widget content.
A Promise that is resolved if the widget is updated and rejected otherwise. It is a native Promise or a jQuery.Promise when you use jQuery.
If you have technical questions, please create a support ticket in the DevExpress Support Center.