Angular DropDownButton Methods

This section describes methods that control the DropDownButton UI component.

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.

jQuery

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Angular

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Vue

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React

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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 \| Function	Device parameters. When you specify 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

|

Function

Device parameters.
When you specify 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, { Properties } from "devextreme/ui/drop_down_button";
// ...
export class AppComponent {
    constructor () {
        DropDownButton.defaultOptions<Properties>({
            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 dxDropDownButton from "devextreme/ui/drop_down_button";
import DropDownButton from "devextreme-react/drop-down-button";

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

export default function App() {
    return (
        <div>
            <DropDownButton id="dropDownButton1" />
            <DropDownButton id="dropDownButton2" />
        </div>
    )
}

dispose()

Disposes of all the resources allocated to the DropDownButton instance.

jQuery

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

JavaScript

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

Angular

Use conditional rendering instead of this method:

app.component.html

<dx-drop-down-button ...
    *ngIf="condition">
</dx-drop-down-button>

Vue

Use conditional rendering instead of this method:

App.vue

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

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

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

React

Use conditional rendering instead of this method:

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;

element()

Gets the root UI component element.

Return Value:

HTMLElement | jQuery

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

jQuery

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Angular

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Vue

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React

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endUpdate()

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

Main article: beginUpdate()

jQuery

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Vue

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React

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focus()

Sets focus on the UI component.

jQuery

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Vue

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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.

jQuery

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Angular

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Vue

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React

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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);