Methods

This section describes members used to manipulate the widget.

beginUpdate()

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

The beginUpdate() and endUpdate() methods allow you to apply several modifications to the component. After the beginUpdate() method is called, the component does not update the UI until the endUpdate() method is called. The usage of these methods prevents excessive component updating when you are changing multiple component settings at once.

defaultOptions(rule)

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

Parameters:
rule: Object

An object specifying default options for the component and the device for which the options must be applied.

Object structure:

An object representing device parameters, or an array of objects representing device parameters, or a function that provides information on the current device as an input parameter and returning a Boolean value.

options: Object

A configuration object with specified options.

The defaultOptions method is a static method supported by the widget class. The following code demonstrates how to specify default options for all buttons in the application executed on the iOS platform.

JavaScript
DevExpress.ui.dxButton.defaultOptions({ 
    device: { platform: "ios" },
    options: {
        text: "Click me"
    }
});

element()

Returns the root HTML element of the widget.

Return Value: jQuery

The root element of the widget.

endUpdate()

Enables the component to refresh after the beginUpdate() method call.

The beginUpdate() and endUpdate() methods allow you to apply several modifications to the component. After the beginUpdate() method is called, the component does not update the UI until the endUpdate() method is called. The usage of these methods prevents excessive component updating when you change multiple component setting at once.

focus()

Sets focus on the widget.

instance()

Returns an instance of this component class.

Return Value: Object

An instance of this component class

Use this method to access other methods of the component.

off(eventName)

Detaches all event handlers from the specified event.

Parameters:
eventName: String

The name of the event to unsubscribe from.

Return Value: Object

The object for which this method is called.

off(eventName, eventHandler)

Detaches a particular event handler from the specified event.

Parameters:
eventName: String

The name of the event to unsubscribe from.

eventHandler: function

The handler to be detached from the specified event.

Return Value: Object

The object for which this method is called.

on(eventName, eventHandler)

Subscribes to a specified event.

Parameters:
eventName: String

The name of the event to be subscribed.

eventHandler: function

An event handler for the specified event.

Return Value: Object

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 the specified events.

Parameters:
events: Object

An object of the following structure: { "eventName1": handler1, "eventName2": handler2, ...}

Return Value: Object

The object for which this method is called.

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

See Also

option()

Returns the configuration options of this component.

Return Value: Object

An object representing the configuration options of this component.

option(optionName)

Gets the value of the specified configuration option of this component.

Parameters:
optionName: String

The name of the option to get.

Return Value: any

The value of the specified option.

If you need to get the value of a configuration option field, specify the path to the required field.

option(optionName, optionValue)

Sets a value to the specified configuration option of this component.

Parameters:
optionName: String

The name of the required option.

optionValue: any

The value you wish to assign to the required option.

To set a value to the configuration option field, specify the path to the required field.

option(options)

Sets one or more options of this component.

Parameters:
options: Object

An object containing the required configuration options.

registerKeyHandler(key, handler)

Registers a handler when a specified key is pressed.

Parameters:
key: String

Specifies the key for which to register a handler.

handler: function

A handler function.

The handler function is called when the specified key is pressed if the widget is focused.

The key argument accepts the following values.

  • "backspace"
  • "tab"
  • "enter"
  • "escape"
  • "pageUp"
  • "pageDown"
  • "end"
  • "home"
  • "leftArrow"
  • "upArrow"
  • "rightArrow"
  • "downArrow"
  • "del"
  • "space"
  • "F"
  • "A"
  • "asterisk"
  • "minus"
NOTE
If you specify a custom handler for a key, the default handler for this key is canceled.

repaint()

Redraws the widget.

After performing some external modifications that lead to a change of the widget container's size or visibility, the widget's state may become invalid. In this instance, use the repaint() method to redraw the widget.

selectItem(itemElement)

Selects the specified item.

Parameters:
itemElement: DOM Node

The DOM node of the item to be selected.

unselectItem(itemElement)

Unselects the specified item.

Parameters:
itemElement: DOM Node

The DOM node of the item whose selection should be cancelled.