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.

clientHeight()

Returns the height of the widget in pixels.

Return Value: Number

The value of the widget height in pixels.

collapseGroup(groupIndex)

Collapses the specified group.

Parameters:
groupIndex: Number

The index of the group to be collapsed.

Return Value: jQuery.Promise

A Promise of the jQuery Deferred object resolved if the group is collapsed and rejected if it is not.

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:
device: Object|Array|function

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"
    }
});

deleteItem(itemElement)

Removes the specified item from the list.

Parameters:
itemElement: DOM Node

The item element node.

Return Value: jQuery.Promise

A Promise of the jQuery Deferred object resolved if the item is deleted and rejected if it is not.

deleteItem(itemIndex)

Removes the specified item from the list.

Parameters:
itemIndex: Number|Object

The index of the list item to delete. If the list is grouped, pass an object with the required group and item indexes, e.g., { group: 0, item: 0 }.

Return Value: jQuery.Promise

A Promise of the jQuery Deferred object resolved if the item is deleted and rejected if it is not.

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.

expandGroup(groupIndex)

Expands the specified group.

Parameters:
groupIndex: Number

The index of the group to be expanded.

Return Value: jQuery.Promise

A Promise of the jQuery Deferred object that is resolved if the group is expanded and rejected if it is not.

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.

isItemSelected(itemElement)

Returns a Boolean value that indicates whether or not the specified item is selected.

Parameters:
itemElement: DOM Node

The item element node.

Return Value: Boolean

A Boolean value specifying whether or not the requested item is selected.

To determine which items are currently selected, use the widget's option method, passing the selectedItems as a parameter.

isItemSelected(itemIndex)

Returns a Boolean value that indicates whether or not the specified item is selected.

Parameters:
itemIndex: Number|Object

The index number of the requested list item. If the list is grouped, pass an object with the required group and item indexes, e.g., { group: 0, item: 0 }.

Return Value: Boolean

A Boolean value specifying whether or not the requested item is selected.

To determine which items are currently selected, use the widget's option method, passing the selectedItems as a parameter.

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.

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.

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.

reload()

Reloads list data.

You can also reload list data using the "pull down" gesture if the pullRefreshEnabled option is set to true.

reorderItem(itemElement, toItemElement)

Moves the specified item to the specified position in the list.

Parameters:
itemElement: DOM Node

The DOM node of the item to be moved.

toItemElement: DOM Node

The DOM node of the item after which the specified item should be placed.

Return Value: jQuery.Promise

A Promise of the jQuery Deferred object resolved if the item is moved and rejected if it is not.

NOTE
This method reorders items in the items array, but it does not affect the dataSource.

reorderItem(itemIndex, toItemIndex)

Moves the specified item to the specified position in the list.

Parameters:
itemIndex: Number|Object

The index number of the item to be moved.

toItemIndex: Number|Object

The index of the item after which the specified item is placed.

Return Value: jQuery.Promise

A Promise of the jQuery Deferred object resolved if the item is moved and rejected if it is not.

If the widget displays a grouped list, the item index should be specified like the following.

JavaScript
{
    group: 1,
    index: 1
}

Where the group property specifies the group index, and the index property specifies the index of the required item within the group.

JavaScript
$("#myList").dxList("instance").reorderItem({
    group: 1,
    index: 4
},
{
    group: 3,
    index: 2
});

This code will move the 4th item of the 1st group to the 3rd position in the 3rd group.

NOTE
This method reorders items in the items array, but it does not affect the dataSource.

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.

scrollBy(distance)

Scrolls the list content by the specified number of pixels.

Parameters:
distance: Number

A distance to be scrolled in pixels.

scrollHeight()

Returns the height of the list content in pixels.

Return Value: Number

The value of the content height in pixels.

scrollTo(location)

Scrolls list content to the specified position.

Parameters:
location: Number

The position to scroll to (in pixels).

scrollToItem(itemElement)

Scrolls the list to the specified item.

Parameters:
itemElement: DOM Node

The target element node.

scrollToItem(itemIndex)

Scrolls the list to the specified item.

Parameters:
itemIndex: Number|Object

The target element index.

If the widget displays a grouped list, specify the target item index using an object containing the following fields.

  • group
    Specifies the index of the group containing the target item.

  • item
    Specifies the item index within the specified group.

JavaScript
var list = $("#myList").dxList("instance");
list.scrollToItem({
    group: 3,
    item: 8
});

scrollTop()

Returns how far the list content is scrolled from the top.

Return Value: Number

The value of the current scroll position from the top in pixels.

selectItem(itemElement)

Selects the specified item from the list.

Parameters:
itemElement: DOM Node

The DOM node of the item to be selected.

selectItem(itemIndex)

Selects the specified item from the list.

Parameters:
itemIndex: Number|Object

The index number of the list item to select. If the list is grouped, pass an object with the required group and item indexes, e.g., { group: 0, item: 0 }.

Note that the result of the method execution depends on the current value of the selectionMode option, which accepts the following values.

  • none
    The method does nothing.

  • single
    The method selects the specified item while the previously selected item becomes unselected.

  • multi and all The method adds the specified item to the list of currently selected items.

unselectItem(itemElement)

Cancels the selection of the specified item.

Parameters:
itemElement: DOM Node

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

unselectItem(itemIndex)

Unselects the specified item from the list.

Parameters:
itemIndex: Number|Object

The index number of the list item to unselect. If the list is grouped, pass an object with the required group and item indexes, e.g., { group: 0, index: 0 }.

updateDimensions()

Updates the widget scrollbar according to widget content size.

Return Value: jQuery.Promise

A Promise of the jQuery Deferred object resolved when the update process is complete.

Use this method to update the position of list items after the widget element was resized.