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Methods

This section describes methods that control the DropDownButton widget.

See Also

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

close()

Closes the drop-down menu.

Return Value:

Promise<void> (jQuery or native)

A Promise that is resolved when the drop-down menu is closed. It is a native Promise or a jQuery.Promise when you use jQuery.

defaultOptions(rule)

Specifies the device-dependent default configuration options for this component.

Parameters:
rule:

Object

The component's default device options.

Object structure:
Name Type Description
device

Device

|

Array<Device>

|

Function

Device parameters.
When specifying a function, get information about the current device from the argument. Return true if the options should be applied to the device.
options

Object

Options to be applied.

defaultOptions is a static method that the widget class supports. The following code demonstrates how to specify default options for all instances of the DropDownButton widget in an application executed on the desktop.

jQuery
JavaScript
DevExpress.ui.dxDropDownButton.defaultOptions({ 
    device: { deviceType: "desktop" },
    options: {
        // Here go the DropDownButton options
    }
});
Angular
TypeScript
import DropDownButton from "devextreme/ui/drop_down_button";
// ...
export class AppComponent {
    constructor () {
        DropDownButton.defaultOptions({
            device: { deviceType: "desktop" },
            options: {
                // Here go the DropDownButton options
            }
        });
    }
}
Vue
<template>
    <div>
        <dx-drop-down-button id="dropDownButton1" />
        <dx-drop-down-button id="dropDownButton2" />
    </div>
</template>
<script>
import DxDropDownButton from "devextreme-vue/drop-down-button";
import DropDownButton from "devextreme/ui/drop_down_button";

DropDownButton.defaultOptions({
    device: { deviceType: "desktop" },
    options: {
        // Here go the DropDownButton options
    }
});

export default {
    components: {
        DxDropDownButton
    }
}
</script>
React
import React from "react";
import dxDropDownButton from "devextreme/ui/drop_down_button";
import DropDownButton from "devextreme-react/drop-down-button";

class App extends React.Component {
    render () {
        dxDropDownButton.defaultOptions({
            device: { deviceType: "desktop" },
            options: {
                // Here go the DropDownButton options
            }
        })
        return (
            <div>
                <DropDownButton id="dropDownButton1" />
                <DropDownButton id="dropDownButton2" />
            </div>
        )
    }
}

export default App;

dispose()

Disposes of all the resources allocated to the DropDownButton instance.

After calling this method, remove the DOM element associated with the widget:

jQuery
JavaScript
$("#myDropDownButton").dxDropDownButton("dispose");
$("#myDropDownButton").remove();
Angular
HTML
<dx-drop-down-button #dropDownButtonVar id="myDropDownButton"></dx-drop-down-button>
TypeScript
import { ..., ViewChild } from "@angular/core";
import { DxDropDownButtonComponent } from "devextreme-angular";
// ...
export class AppComponent {
    @ViewChild("dropDownButtonVar", { static: false }) dropDownButton: DxDropDownButtonComponent;
    // Prior to Angular 8
    // @ViewChild("dropDownButtonVar") dropDownButton: DxDropDownButtonComponent;

    removeDropDownButton (e) {
        this.dropDownButton.instance.dispose();
        document.getElementById("myDropDownButton").remove();
    }
}

element()

Gets the root widget element.

Return Value:

Element (jQuery or HTML)

An HTML element or a jQuery element when you use jQuery.

See Also

endUpdate()

Refreshes the widget after a call of the beginUpdate() method.

Main article: beginUpdate()

See Also

focus()

Sets focus on the widget.

See Also

getDataSource()

Gets the DataSource instance.

Return Value:

DataSource

The DataSource instance.

NOTE
This method returns the DataSource instance even if the widget's dataSource option was given a simple array.
See Also

getInstance(element)

Gets the instance of a widget found using its DOM node.

Parameters:
element:

DOM Node

|

jQuery

The widget's container.

Return Value:

Object

The widget's instance.

getInstance is a static method that the widget class supports. The following code demonstrates how to get the DropDownButton instance found in an element with the myDropDownButton ID:

// Modular approach
import DropDownButton from "devextreme/ui/drop_down_button";
...
let element = document.getElementById("myDropDownButton");
let instance = DropDownButton.getInstance(element) as DropDownButton;

// Non-modular approach
let element = document.getElementById("myDropDownButton");
let instance = DevExpress.ui.dxDropDownButton.getInstance(element);
See Also

instance()

Gets the widget's instance. Use it to access other methods of the widget.

Return Value:

DropDownButton

This widget's instance.

See Also

off(eventName)

Detaches all event handlers from a single event.

Parameters:
eventName:

String

The event's name.

Return Value:

DropDownButton

The object for which this method is called.

See Also

off(eventName, eventHandler)

Detaches a particular event handler from a single event.

Parameters:
eventName:

String

The event's name.

eventHandler:

Function

The event's handler.

Return Value:

DropDownButton

The object for which this method is called.

See Also

on(eventName, eventHandler)

Subscribes to an event.

Parameters:
eventName:

String

The event's name.

eventHandler:

Function

The event's handler.

Return Value:

DropDownButton

The object for which this method is called.

Use this method to subscribe to one of the events listed in the Events section.

See Also

on(events)

Subscribes to events.

Parameters:
events:

Object

Events with their handlers: { "eventName1": handler1, "eventName2": handler2, ...}

Return Value:

DropDownButton

The object for which this method is called.

Use this method to subscribe to several events with one method call. Available events are listed in the Events section.

See Also

open()

Opens the drop-down menu.

Return Value:

Promise<void> (jQuery or native)

A Promise that is resolved when the drop-down menu is opened. It is a native Promise or a jQuery.Promise when you use jQuery.

option()

Gets all widget options.

Return Value:

Object

The widget's options.

See Also

option(optionName)

Gets the value of a single option.

Parameters:
optionName:

String

The option's name or full path.

Return Value: any

This option's value.

See Also

option(optionName, optionValue)

Updates the value of a single option.

Parameters:
optionName:

String

The option's name or full path.

optionValue: any

This option's new value.

See Also

option(options)

Updates the values of several options.

Parameters:
options:

Object

Options with their new values.

See Also

registerKeyHandler(key, handler)

Registers a handler to be executed when a user presses a specific key.

Parameters:
key:

String

A key.

handler:

Function

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

repaint()

Repaints the widget without reloading data. Call it to update the widget's markup.

See Also

resetOption(optionName)

Resets an option to its default value.

Parameters:
optionName:

String

An option's name.

See Also

toggle()

Opens or closes the drop-down menu, reversing the current state.

Return Value:

Promise<void> (jQuery or native)

A Promise that is resolved when the drop-down menu is opened or closed. It is a native Promise or a jQuery.Promise when you use jQuery.

toggle(visibility)

Opens or closes the drop-down menu, depending on the argument.

Parameters:
visibility:

Boolean

Pass true to open the drop-down menu; false to close.

Return Value:

Promise<void> (jQuery or native)

A Promise that is resolved when the drop-down menu is opened or closed. It is a native Promise or a jQuery.Promise when you use jQuery.