Methods

This section describes methods that control the DropDownButton UI component.

See Also

beginUpdate()

Prevents the UI component from refreshing until the endUpdate() method is called.

The beginUpdate() and endUpdate() methods prevent the UI component from excessive updates when you are changing multiple UI component settings at once. After the beginUpdate() method is called, the UI component 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 properties for this component.

Parameters:
rule:

Object

The component's default device properties.

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 properties should be applied to the device.

options

Object

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 DropDownButton UI component in an application executed on the desktop.

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

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 properties
            }
        })
        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 UI component:

JavaScript
$("#myDropDownButton").dxDropDownButton("dispose");
$("#myDropDownButton").remove();

Use this method only if the UI component was created with jQuery or pure JavaScript. In Angular, Vue, and React, use conditional rendering:

Angular
app.component.html
<dx-drop-down-button ...
    *ngIf="condition">
</dx-drop-down-button>
Vue
App.vue
<template>
    <DxDropDownButton ...
        v-if="condition">
    </DxDropDownButton>
</template>

<script>
import DxDropDownButton from 'devextreme-vue/drop-down-button';

export default {
    components: {
        DxDropDownButton
    }
}
</script>
React
App.js
import React from 'react';

import DropDownButton from 'devextreme-react/drop-down-button';

function DxDropDownButton(props) {
    if (!props.shouldRender) {
        return null;
    }

    return (
        <DropDownButton ... >    
        </DropDownButton>
    );
}

class App extends React.Component {
    render() {
        return (
            <DxDropDownButton shouldRender="condition" />
        );
    }
}
export default App;
See Also

element()

Gets the root UI component element.

Return Value:

HTMLElement | jQuery

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

See Also

endUpdate()

Refreshes the UI component after a call of the beginUpdate() method.

Main article: beginUpdate()

See Also

focus()

Sets focus on the UI component.

See Also

getDataSource()

Gets the DataSource instance.

Return Value:

DataSource

The DataSource instance.

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

getInstance(element)

Gets the instance of a UI component found using its DOM node.

Parameters:
element:

Element

|

jQuery

The UI component's container.

Return Value:

Object

The UI component's instance.

getInstance is a static method that the UI component 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 UI component's instance. Use it to access other methods of the UI component.

Return Value:

DropDownButton

This UI component'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()

Return Value:

Object

The UI component's properties.

option(optionName)

Gets the value of a single property.

Parameters:
optionName:

String

The property's name or full path.

Return Value: any

This property's value.

option(optionName, optionValue)

Updates the value of a single property.

Parameters:
optionName:

String

The property's name or full path.

optionValue: any

This property's new value.

option(options)

Updates the values of several properties.

Parameters:
options:

Object

Options with their new values.

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 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()

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

See Also

resetOption(optionName)

Resets an property to its default value.

Parameters:
optionName:

String

An property'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.