Angular DropDownBox Methods

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.

Name

Type

Description

device

Device

|

Array<Device>

|

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

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 DropDownBox UI component in an application executed on the desktop.

jQuery

JavaScript

DevExpress.ui.dxDropDownBox.defaultOptions({ 
    device: { deviceType: "desktop" },
    options: {
        // Here go the DropDownBox properties
    }
});

Angular

TypeScript

import DropDownBox from "devextreme/ui/drop_down_box";
// ...
export class AppComponent {
    constructor () {
        DropDownBox.defaultOptions({
            device: { deviceType: "desktop" },
            options: {
                // Here go the DropDownBox properties
            }
        });
    }
}

Vue

<template>
    <div>
        <DxDropDownBox id="dropDownBox1" />
        <DxDropDownBox id="dropDownBox2" />
    </div>
</template>
<script>
import DxDropDownBox from "devextreme-vue/drop-down-box";
import DropDownBox from "devextreme/ui/drop_down_box";

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

export default {
    components: {
        DxDropDownBox
    }
}
</script>

React

import React, {useEffect} from "react";
import dxDropDownBox from "devextreme/ui/drop_down_box";
import DropDownBox from "devextreme-react/drop-down-box";

export default function App() {
    useEffect(() => { 
        dxDropDownBox.defaultOptions({
            device: { deviceType: "desktop" },
            options: {
                // Here go the DropDownBox properties
            }
        })
    });

    return (
        <div>
            <DropDownBox id="dropDownBox1" />
            <DropDownBox id="dropDownBox2" />
        </div>
    )
}

dispose()

Disposes of all the resources allocated to the DropDownBox instance.

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

JavaScript

$("#myDropDownBox").dxDropDownBox("dispose");
$("#myDropDownBox").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-box ...
    *ngIf="condition">
</dx-drop-down-box>

Vue

App.vue

<template>
    <DxDropDownBox ...
        v-if="condition">
    </DxDropDownBox>
</template>

<script>
import DxDropDownBox from 'devextreme-vue/drop-down-box';

export default {
    components: {
        DxDropDownBox
    }
}
</script>

React

App.js

import React from 'react';

import DropDownBox from 'devextreme-react/drop-down-box';

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

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

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

element()

Gets the root UI component element.

Return Value:

HTMLElement | jQuery

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

endUpdate()

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

Main article: beginUpdate()

field()

Gets the UI component's <input> element.

Return Value:

HTMLElement | jQuery

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

focus()

Sets focus to the input element representing the UI component.

getButton(name)

Gets an instance of a custom action button.

Parameters:

name:

The button's name.

Return Value:

Button

| undefined

The Button UI component's instance.

Use the returned button instance to call the Button UI component's methods, for example, focus():

jQuery

index.js

const myCustomButton = $("#dropDownBoxContainer").dxDropDownBox("getButton", "myCustomButton");
myCustomButton.focus();

Angular

app.component.ts

app.component.html

import { Component, ViewChild } from '@angular/core';
import { DxDropDownBoxComponent } from 'devextreme-angular';

@Component({
    selector: 'app-root',
    templateUrl: './app.component.html',
    styleUrls: ['./app.component.css']
})
export class AppComponent {
    @ViewChild('dropDownBoxRef', { static: false }) dropDownBox: DxDropDownBoxComponent;
    // Prior to Angular 8
    // @ViewChild('dropDownBoxRef') dropDownBox: DxDropDownBoxComponent;

    setFocus() {
        this.dropDownBox.instance.getButton('myCustomButton').focus();
    }
}

<dx-drop-down-box #dropDownBoxRef ... >
</dx-drop-down-box>

Vue

App.vue

<template>
    <DxDropDownBox ...
        :ref="dropDownBoxRef">
    </DxDropDownBox>
</template>

<script>
import 'devextreme/dist/css/dx.common.css';
import 'devextreme/dist/css/dx.light.css';

import DxDropDownBox from 'devextreme-vue/drop-down-box';

export default {
    components: {
        DxDropDownBox
    },

    data() {
        return {
            dropDownBoxRef
        }
    },

    methods: {
        setFocus() {
            this.dropDownBox.getButton('myCustomButton').focus();
        }
    },

    computed: {
        dropDownBox: function() {
            return this.$refs[dropDownBoxRef].instance;
        }
    }
}
</script>

React

App.js

import React from 'react';

import 'devextreme/dist/css/dx.common.css';
import 'devextreme/dist/css/dx.light.css';

import DropDownBox from 'devextreme-react/drop-down-box';

class App extends React.Component {
    constructor(props) {
        super(props);

        this.dropDownBoxRef = React.createRef();

        this.setFocus = () => {
            this.dropDownBox.getButton('myCustomButton').focus();
        };
    }

    get dropDownBox() {
        return this.dropDownBoxRef.current.instance;
    }

    render() {
        return (
            <DropDownBox ...
                ref={this.dropDownBoxRef}>
            </DropDownBox>
        );
    }
}
export default App;

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.

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:

The UI component's instance.

getInstance is a static method that the UI component class supports. The following code demonstrates how to get the DropDownBox instance found in an element with the myDropDownBox ID:

// Modular approach
import DropDownBox from "devextreme/ui/drop_down_box";
...
let element = document.getElementById("myDropDownBox");
let instance = DropDownBox.getInstance(element) as DropDownBox;

// Non-modular approach
let element = document.getElementById("myDropDownBox");
let instance = DevExpress.ui.dxDropDownBox.getInstance(element);

instance()

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

Return Value:

This UI component's instance.

off(eventName)

Detaches all event handlers from a single event.

Parameters:

eventName:

The event's name.

Return Value:

The object for which this method is called.

off(eventName, eventHandler)

Detaches a particular event handler from a single event.

Parameters:

eventName:

The event's name.

eventHandler:

The event's handler.

Return Value:

The object for which this method is called.

on(eventName, eventHandler)

Subscribes to an event.

Parameters:

eventName:

The event's name.

eventHandler:

The event's handler.

Return Value:

The object for which this method is called.

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

on(events)

Subscribes to events.

Parameters:

events:

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

Return Value:

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.

open()

Opens the drop-down editor.

option()

Gets all UI component properties.

Return Value:

The UI component's properties.

option(optionName)

Gets the value of a single property.

Parameters:

optionName:

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:

The property's name or full path.

optionValue: any

This property's new value.

option(options)

Updates the values of several properties.

Parameters:

options:

Options with their new values.

registerKeyHandler(key, handler)

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

Parameters:

key:

A key.

handler:

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.

repaint()

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

reset()

Resets the value property to the default value.

resetOption(optionName)

Resets a property to its default value.

Parameters:

optionName: