beginUpdate()
Postpones rendering that can negatively affect performance until the endUpdate() method is called.
The beginUpdate() and endUpdate() methods reduce the number of renders in cases where extra rendering can negatively affect performance.
See Also
defaultOptions(rule)
Name | Type | Description |
---|---|---|
device | | |
Device parameters. |
options |
Options to be applied. |
defaultOptions is a static method that the UI component class supports. The following code demonstrates how to specify default properties for all instances of the Menu UI component in an application executed on the desktop.
jQuery
DevExpress.ui.dxMenu.defaultOptions({ device: { deviceType: "desktop" }, options: { // Here go the Menu properties } });
Angular
import Menu, { Properties } from "devextreme/ui/menu"; // ... export class AppComponent { constructor () { Menu.defaultOptions<Properties>({ device: { deviceType: "desktop" }, options: { // Here go the Menu properties } }); } }
Vue
<template> <div> <DxMenu id="menu1" /> <DxMenu id="menu2" /> </div> </template> <script> import DxMenu from "devextreme-vue/menu"; import Menu from "devextreme/ui/menu"; Menu.defaultOptions({ device: { deviceType: "desktop" }, options: { // Here go the Menu properties } }); export default { components: { DxMenu } } </script>
React
import dxMenu from "devextreme/ui/menu"; import Menu from "devextreme-react/menu"; dxMenu.defaultOptions({ device: { deviceType: "desktop" }, options: { // Here go the Menu properties } }); export default function App() { return ( <div> <Menu id="menu1" /> <Menu id="menu2" /> </div> ) }
You can also set rules for multiple device types:
jQuery
const devicesConfig = [ { deviceType: 'desktop' }, { deviceType: 'tablet' }, { deviceType: 'phone' }, ]; devicesConfig.forEach(deviceConfig => { DevExpress.ui.dxMenu.defaultOptions({ device: deviceConfig, options: { // Here go the Menu properties } }); });
Angular
import Menu, { Properties } from "devextreme/ui/menu"; // ... export class AppComponent { constructor () { const devicesConfig = [ { deviceType: 'desktop' }, { deviceType: 'tablet' }, { deviceType: 'phone' }, ]; devicesConfig.forEach(deviceConfig => { Menu.defaultOptions<Properties>({ device: deviceConfig, options: { // Here go the Menu properties } }); }); } }
Vue
<template> <div> <DxMenu /> </div> </template> <script> import DxMenu from "devextreme-vue/menu"; import Menu from "devextreme/ui/menu"; const devicesConfig = [ { deviceType: 'desktop' }, { deviceType: 'tablet' }, { deviceType: 'phone' }, ]; devicesConfig.forEach(deviceConfig => { Menu.defaultOptions({ device: deviceConfig, options: { // Here go the Menu properties } }); }); export default { components: { DxMenu } } </script>
React
import dxMenu from "devextreme/ui/menu"; import Menu from "devextreme-react/menu"; const devicesConfig = [ { deviceType: 'desktop' }, { deviceType: 'tablet' }, { deviceType: 'phone' }, ]; devicesConfig.forEach(deviceConfig => { dxMenu.defaultOptions({ device: deviceConfig, options: { // Here go the Menu properties } }); }); export default function App() { return ( <div> <Menu /> </div> ) }
dispose()
jQuery
After calling this method, remove the DOM element associated with the UI component:
$("#myMenu").dxMenu("dispose"); $("#myMenu").remove();
Angular
Use conditional rendering instead of this method:
<dx-menu ... *ngIf="condition"> </dx-menu>
Vue
Use conditional rendering instead of this method:
<template> <DxMenu ... v-if="condition"> </DxMenu> </template> <script> import DxMenu from 'devextreme-vue/menu'; export default { components: { DxMenu } } </script>
React
Use conditional rendering instead of this method:
import React from 'react'; import Menu from 'devextreme-react/menu'; function DxMenu(props) { if (!props.shouldRender) { return null; } return ( <Menu ... > </Menu> ); } class App extends React.Component { render() { return ( <DxMenu shouldRender="condition" /> ); } } export default App;
endUpdate()
Refreshes the UI component after a call of the beginUpdate() method.
The beginUpdate() and endUpdate() methods reduce the number of renders in cases where extra rendering can negatively affect performance.
See Also
getDataSource()
Gets the DataSource instance.
See Also
getInstance(element)
getInstance is a static method that the UI component class supports. The following code demonstrates how to get the Menu instance found in an element with the myMenu
ID:
// Modular approach import Menu from "devextreme/ui/menu"; ... let element = document.getElementById("myMenu"); let instance = Menu.getInstance(element) as Menu; // Non-modular approach let element = document.getElementById("myMenu"); let instance = DevExpress.ui.dxMenu.getInstance(element);
See Also
on(eventName, eventHandler)
Use this method to subscribe to one of the events listed in the Events section.
See Also
on(events)
Use this method to subscribe to several events with one method call. Available events are listed in the Events section.
See Also
registerKeyHandler(key, handler)
A handler. Accepts the keydown event as the argument. It is a EventObject 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
repaint()
Renders the component again without reloading data. Use the method to update the component's markup and appearance dynamically.
The repaint()
method re-initializes the component with new settings, resetting its state and history.
See Also
- reload() in DataSource | List
- refresh() in DataGrid | TreeList