# Class yii\bootstrap\Dropdown

Inheritance | yii\bootstrap\Dropdown » yii\bootstrap\Widget » yii\base\Widget » yii\base\Component » yii\base\BaseObject
Implements | yii\base\Configurable, yii\base\ViewContextInterface
Uses Traits | yii\bootstrap\BootstrapWidgetTrait
Available since version | 2.0
Source Code | https://github.com/yiisoft/yii2-bootstrap/blob/master/Dropdown.php

Dropdown renders a Bootstrap dropdown menu component.

For example,

    <div class="dropdown">
        <a href="#" data-toggle="dropdown" class="dropdown-toggle">Label <b class="caret"></b></a>
        <?php
            echo Dropdown::widget([
                'items' => [
                    ['label' => 'DropdownA', 'url' => '/'],
                    ['label' => 'DropdownB', 'url' => '#'],
                ],
            ]);
        ?>
    </div>

See also http://getbootstrap.com/javascript/#dropdowns.

## Public Properties

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Property | Type | Description | Defined By
--- | --- | --- | ---
$autoIdPrefix | string | The prefix to the automatically generated widget IDs. | yii\base\Widget
$behaviors | yii\base\Behavior[] | List of behaviors attached to this component. This property is read-only. | yii\base\Component
$clientEvents | array | The event handlers for the underlying Bootstrap JS plugin. | yii\bootstrap\BootstrapWidgetTrait
$clientOptions | array | The options for the underlying Bootstrap JS plugin. | yii\bootstrap\BootstrapWidgetTrait
$counter | integer | A counter used to generate $id for widgets. | yii\base\Widget
$encodeLabels | boolean | Whether the labels for header items should be HTML-encoded. | yii\bootstrap\Dropdown
$id | string|null | ID of the widget. Note that the type of this property differs in getter and setter. See getId() and setId() for details. | yii\base\Widget
$items | array | List of menu items in the dropdown. | yii\bootstrap\Dropdown
$options | array | The HTML attributes for the widget container tag. | yii\bootstrap\Widget
$stack | yii\base\Widget[] | The widgets that are currently being rendered (not ended). | yii\base\Widget
$submenuOptions | array|null | The HTML attributes for sub-menu container tags. | yii\bootstrap\Dropdown
$view | yii\web\View | The view object that can be used to render views or view files. Note that the type of this property differs in getter and setter. See getView() and setView() for details. | yii\base\Widget
$viewPath | string | The directory containing the view files for this widget. This property is read-only. | yii\base\Widget

## Public Methods

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Method | Description | Defined By
--- | --- | ---
__call() | Calls the named method which is not a class method. | yii\base\Component
__clone() | This method is called after the object is created by cloning an existing one. | yii\base\Component
__construct() | Constructor. | yii\base\BaseObject
__get() | Returns the value of a component property. | yii\base\Component
__isset() | Checks if a property is set, i.e. defined and not null. | yii\base\Component
__set() | Sets the value of a component property. | yii\base\Component
__unset() | Sets a component property to be null. | yii\base\Component
afterRun() | This method is invoked right after a widget is executed. | yii\base\Widget
attachBehavior() | Attaches a behavior to this component. | yii\base\Component
attachBehaviors() | Attaches a list of behaviors to the component. | yii\base\Component
beforeRun() | This method is invoked right before the widget is executed. | yii\base\Widget
begin() | Begins a widget. | yii\base\Widget
behaviors() | Returns a list of behaviors that this component should behave as. | yii\base\Component
canGetProperty() | Returns a value indicating whether a property can be read. | yii\base\Component
canSetProperty() | Returns a value indicating whether a property can be set. | yii\base\Component
className() | Returns the fully qualified name of this class. | yii\base\BaseObject
detachBehavior() | Detaches a behavior from the component. | yii\base\Component
detachBehaviors() | Detaches all behaviors from the component. | yii\base\Component
end() | Ends a widget. | yii\base\Widget
ensureBehaviors() | Makes sure that the behaviors declared in behaviors() are attached to this component. | yii\base\Component
getBehavior() | Returns the named behavior object. | yii\base\Component
getBehaviors() | Returns all behaviors attached to this component. | yii\base\Component
getId() | Returns the ID of the widget. | yii\base\Widget
getView() |  | yii\bootstrap\BootstrapWidgetTrait
getViewPath() | Returns the directory containing the view files for this widget. | yii\base\Widget
hasEventHandlers() | Returns a value indicating whether there is any handler attached to the named event. | yii\base\Component
hasMethod() | Returns a value indicating whether a method is defined. | yii\base\Component
hasProperty() | Returns a value indicating whether a property is defined for this component. | yii\base\Component
init() | Initializes the widget. | yii\bootstrap\Dropdown
off() | Detaches an existing event handler from this component. | yii\base\Component
on() | Attaches an event handler to an event. | yii\base\Component
render() | Renders a view. | yii\base\Widget
renderFile() | Renders a view file. | yii\base\Widget
run() | Renders the widget. | yii\bootstrap\Dropdown
setId() | Sets the ID of the widget. | yii\base\Widget
setView() | Sets the view object to be used by this widget. | yii\base\Widget
trigger() | Triggers an event. | yii\base\Component
widget() | Creates a widget instance and runs it. | yii\base\Widget

## Protected Methods

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Method | Description | Defined By
--- | --- | ---
registerClientEvents() | Registers JS event handlers that are listed in $clientEvents. | yii\bootstrap\BootstrapWidgetTrait
registerPlugin() | Registers a specific Bootstrap plugin and the related events | yii\bootstrap\BootstrapWidgetTrait
renderItems() | Renders menu items. | yii\bootstrap\Dropdown

## Events

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Event | Type | Description | Defined By
--- | --- | --- | ---
EVENT_AFTER_RUN | yii\base\WidgetEvent | An event raised right after executing a widget. (available since version 2.0.11) | yii\base\Widget
EVENT_BEFORE_RUN | yii\base\WidgetEvent | An event raised right before executing a widget. (available since version 2.0.11) | yii\base\Widget
EVENT_INIT | yii\base\Event | An event that is triggered when the widget is initialized via init(). (available since version 2.0.11) | yii\base\Widget

## Property Details

$encodeLabels public property

Whether the labels for header items should be HTML-encoded.

public boolean $encodeLabels = true
$items public property

List of menu items in the dropdown. Each array element can be either an HTML string, or an array representing a single menu with the following structure:

- label: string, required, the label of the item link.
- encode: bool, optional, whether to HTML-encode item label.
- url: string|array, optional, the URL of the item link. This will be processed by yii\helpers\Url::to(). If not set, the item will be treated as a menu header when the item has no sub-menu.
- visible: bool, optional, whether this menu item is visible. Defaults to true.
- linkOptions: array, optional, the HTML attributes of the item link.
- options: array, optional, the HTML attributes of the item.
- items: array, optional, the submenu items. The structure is the same as this property. Note that Bootstrap doesn't support dropdown submenu. You have to add your own CSS styles to support it.
- submenuOptions: array, optional, the HTML attributes for sub-menu container tag. If specified it will be merged with $submenuOptions.

To insert divider use `<li role="presentation" class="divider"></li>`.

public array $items = []
$submenuOptions public property (available since version 2.0.5)

The HTML attributes for sub-menu container tags. If not set - $options value will be used for it.

public array|null $submenuOptions = null

## Method Details

init() public method

Initializes the widget.

If you override this method, make sure you call the parent implementation first.

public void init ( )

renderItems() protected method

Renders menu items.

protected string renderItems ( $items, $options = [] )
$items | array | The menu items to be rendered
$options | array | The container HTML attributes
return | string | The rendering result.
throws | yii\base\InvalidConfigException | if the label option is not specified in one of the items.

run() public method

Renders the widget.

public void run ( )