# GenericDropdownMenu

> GenericDropdownMenu allows you to display contextual menus with default textual options or any VisualElement.

## Definition

* **Type:** Class
* **Namespace:** [UnityEngine.UIElements](/engine/6000.3/script-reference/unityengine/uielements.md)
* **Assembly:** UnityEngine.UIElementsModule
* **Inherits from:** [AbstractGenericMenu](/engine/6000.3/script-reference/unityengine/uielements/abstractgenericmenu.md)

```csharp
public class GenericDropdownMenu : AbstractGenericMenu
```

## Remarks

The GenericDropdownMenu is a generic implementation of a dropdown menu that you can use in both Editor UI and runtime UI.

The following example creates a dropdown menu with three items. It displays the menu when the user clicks the button. The example also demonstrates how to set the width of the dropdown menu with the `DropDown` method.

## Examples

```csharp
using UnityEditor;
using UnityEngine;
using UnityEngine.UIElements;

public class MenuExample : EditorWindow
{

    [MenuItem("Window/UI Toolkit/MenuExample")]
    public static void ShowExample()
    {
        MenuExample wnd = GetWindow<MenuExample>();
        wnd.titleContent = new GUIContent("MenuExample");
    }
    public void CreateGUI()
    {
        VisualElement root = rootVisualElement;

        // Create a button.
        var button = new Button();
        button.text = "Button";
        button.style.width = 70;
        button.RegisterCallback<FocusInEvent>(OnFocusIn);
        button.RegisterCallback<FocusOutEvent>(OnFocusOut);

        // Create a dropdown menu with three items.
        var menu = new GenericDropdownMenu();
        menu.AddItem("Item 1", false, a => { Debug.Log("Item 1 was selected"); }, null);
        menu.AddItem("Item 2", false, a => { Debug.Log("Item 2 was selected"); }, null);
        menu.AddItem("Item 3 has a very very long label", false, a => { Debug.Log("Item 3 was selected"); }, null);

        // Return focus to the button when the menu is closed.
        menu.onClose += () =>
        {
            button.Focus();
        };

        // When the button is clicked, the dropdown menu is displayed aligned with the button's world boundaries.
        button.clicked += () =>
        {
            // The third and the fourth parameters of the DropDown set the width of the dropdown menu.
            // This sets the width of the dropdown menu to the width of the container.
            menu.DropDown(button.worldBound, button, false);
            // This sets the width of the dropdown menu to the width of the button.
            // menu.DropDown(button.worldBound, button, true, false);
            // This sets the width of the dropdown menu to the width of the longest item.
            // menu.DropDown(button.worldBound, button, true, true);
        };

        root.Add(button);
    }

    void OnFocusIn(FocusInEvent evt)
    {
        // When the button receives focus, set the background color to a lighter gray.
        var button = evt.currentTarget as Button;
        button.style.backgroundColor = Color.dimGray;
    }

    void OnFocusOut(FocusOutEvent evt)
    {
        // When the button loses focus, return its color to the default color.
        var button = evt.currentTarget as Button;

        // Menu also steals focus, but we don't want to reset the color in that case.
        if (evt.relatedTarget is VisualElement { userData: GenericDropdownMenu menu } && menu.targetElement == button)
        {
            return;
        }

        button.style.backgroundColor = StyleKeyword.Null;
    }
}
```

## Static Fields

| Value                                                                                                                                  | Description                                                                             |
| -------------------------------------------------------------------------------------------------------------------------------------- | --------------------------------------------------------------------------------------- |
| [checkmarkUssClassName](/engine/6000.3/script-reference/unityengine/uielements/genericdropdownmenu/checkmarkussclassname.md)           | USS class name of separators in elements of this type.                                  |
| [containerInnerUssClassName](/engine/6000.3/script-reference/unityengine/uielements/genericdropdownmenu/containerinnerussclassname.md) | USS class name of inner containers in elements of this type.                            |
| [containerOuterUssClassName](/engine/6000.3/script-reference/unityengine/uielements/genericdropdownmenu/containerouterussclassname.md) | USS class name of outer containers in elements of this type.                            |
| [contentWidthUssClassName](/engine/6000.3/script-reference/unityengine/uielements/genericdropdownmenu/contentwidthussclassname.md)     | USS class name that's added when the GenericDropdownMenu fits the width of its content. |
| [itemContentUssClassName](/engine/6000.3/script-reference/unityengine/uielements/genericdropdownmenu/itemcontentussclassname.md)       | USS class name of labels in elements of this type.                                      |
| [itemUssClassName](/engine/6000.3/script-reference/unityengine/uielements/genericdropdownmenu/itemussclassname.md)                     | USS class name of labels in elements of this type.                                      |
| [labelUssClassName](/engine/6000.3/script-reference/unityengine/uielements/genericdropdownmenu/labelussclassname.md)                   | USS class name of labels in elements of this type.                                      |
| [separatorUssClassName](/engine/6000.3/script-reference/unityengine/uielements/genericdropdownmenu/separatorussclassname.md)           | USS class name of separators in elements of this type.                                  |
| [ussClassName](/engine/6000.3/script-reference/unityengine/uielements/genericdropdownmenu/ussclassname.md)                             | USS class name of elements of this type.                                                |

## Constructors

| Constructor                                                                                                 | Description                                                 |
| ----------------------------------------------------------------------------------------------------------- | ----------------------------------------------------------- |
| [GenericDropdownMenu()](/engine/6000.3/script-reference/unityengine/uielements/genericdropdownmenu/ctor.md) | Initializes and returns an instance of GenericDropdownMenu. |

## Properties

| Property                                                                                                           | Description                                                                                                                                                                                                                                                                                                                                                                                             |
| ------------------------------------------------------------------------------------------------------------------ | ------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------- |
| [contentContainer](/engine/6000.3/script-reference/unityengine/uielements/genericdropdownmenu/contentcontainer.md) | Returns the content container for the [GenericDropdownMenu](/engine/6000.3/script-reference/unityengine/uielements/genericdropdownmenu.md). Allows users to create their own dropdown menu if they don't want to use the default implementation. It contains a reference to the menu in its [VisualElement.userData](/engine/6000.3/script-reference/unityengine/uielements/visualelement/userdata.md). |
| [targetElement](/engine/6000.3/script-reference/unityengine/uielements/genericdropdownmenu/targetelement.md)       | Returns the element that determines which root to use as the menu's parent.                                                                                                                                                                                                                                                                                                                             |

## Methods

| Method                                                                                                           | Description                                                            |
| ---------------------------------------------------------------------------------------------------------------- | ---------------------------------------------------------------------- |
| [AddDisabledItem](/engine/6000.3/script-reference/unityengine/uielements/genericdropdownmenu/adddisableditem.md) | Adds a disabled item to this menu using a default VisualElement.       |
| [AddItem](/engine/6000.3/script-reference/unityengine/uielements/genericdropdownmenu/additem.md)                 | Adds an item to this menu using a default VisualElement.               |
| [AddSeparator](/engine/6000.3/script-reference/unityengine/uielements/genericdropdownmenu/addseparator.md)       | Adds a visual separator after the previously added items in this menu. |
| [DropDown](/engine/6000.3/script-reference/unityengine/uielements/genericdropdownmenu/dropdown.md)               | Displays the menu at the specified position.                           |

## Events

| Member                                                                                           | Description                                          |
| ------------------------------------------------------------------------------------------------ | ---------------------------------------------------- |
| [onClose](/engine/6000.3/script-reference/unityengine/uielements/genericdropdownmenu/onclose.md) | An action that is invoked after the menu is closed.  |
| [onOpen](/engine/6000.3/script-reference/unityengine/uielements/genericdropdownmenu/onopen.md)   | An action that is invoked before the menu is opened. |