Version: 2022.1
UXML element DoubleField
UXML element EnumField

UXML element DropdownField

A DropdownField lets users choose a value from a list. When clicking on the control, it opens a drawer that presents multiple options, allowing users to select one. If you want to always display all the choices, use RadioButtonGroup.

Respond to user actions

A DropdownField responds to Change events.

You can bind a DropdownField to a string variable that holds the selected choice value.

Add options for a DropdownField in UI Builder

To add options for a DropdownField, in the InspectorA Unity window that displays information about the currently selected GameObject, asset or project settings, allowing you to inspect and edit the values. More info
See in Glossary
of the DropdownField, enter the options separated by commas in Choices.

To set the default value, in the Inspector of the DropdownField, enter the numbering sequence of the option in Index, starting at 0.

Create a DropdownField in C# script

The following C# code snippets create a DropdownField with three options. The DropdownField selects the first option by default.

var dropdown = new DropdownField("Options", new List<string> { "Option 1", "Option 2", "Option 3" }, 0);
dropdown.RegisterValueChangedCallback(evt => Debug.Log(evt.newValue));
rootVisualElement.Add(dropdown);

Examples

The best way to learn how to use DropdownField is to try an example. To see a DropdownField example, in Unity, select Window > UI Toolkit > Samples > DropdownField.

C# base class and namespace

C# class: DropdownField
Namespace: UnityEngine.UIElements
Base class: PopupField_1

Inherited attributes

This element inherits the following attributes from its base class:

Name Type Description
binding-path string Path of the target property to be bound.
choices string The list of choices to display in the popup menu.
focusable boolean True if the element can be focused.
index int The currently selected index in the popup menu.
label string The string representing the label that will appear beside the field.
tabindex int An integer used to sort focusables in the focus ring. Must be greater than or equal to zero.

This element also inherits the following attributes from VisualElement:

Name Type Description
content-container string child elements are added to this element, usually this
name string The name of this VisualElement.

Use this property to write USS selectors that target a specific element. The standard practice is to give an element a unique name.
picking-mode UIElements.PickingMode Determines if this element can be pick during mouseEvents or IPanel.Pick queries.
style string Reference to the style object of this element.

Contains data computed from USS files or inline styles written to this object in C#.
tooltip string Text to display inside an information box after the user hovers the element for a small amount of time.
usage-hints UIElements.UsageHints A combination of hint values that specify high-level intended usage patterns for the VisualElement. This property can only be set when the VisualElement is not yet part of a Panel. Once part of a Panel, this property becomes effectively read-only, and attempts to change it will throw an exception. The specification of proper UsageHints drives the system to make better decisions on how to process or accelerate certain operations based on the anticipated usage pattern. Note that those hints do not affect behavioral or visual results, but only affect the overall performance of the panel and the elements within. It’s advised to always consider specifying the proper UsageHints, but keep in mind that some UsageHints might be internally ignored under certain conditions (e.g. due to hardware limitations on the target platform).
view-data-key string Used for view data persistence (ie. tree expanded states, scroll position, zoom level).

This is the key used to save/load the view data from the view data store. Not setting this key will disable persistence for this VisualElement.

USS classes

The following table lists all the C# public property names and their related USS selector.

C# property USS selector Description
ussClassName .unity-popup-field USS class name of elements of this type.
labelUssClassName .unity-popup-field__label USS class name of labels in elements of this type.
inputUssClassName .unity-popup-field__input USS class name of input elements in elements of this type.
ussClassName .unity-base-popup-field USS class name of elements of this type.
textUssClassName .unity-base-popup-field__text USS class name of text elements in elements of this type.
arrowUssClassName .unity-base-popup-field__arrow USS class name of arrow indicators in elements of this type.
labelUssClassName .unity-base-popup-field__label USS class name of labels in elements of this type.
inputUssClassName .unity-base-popup-field__input USS class name of input elements in elements of this type.
ussClassName .unity-base-field USS class name of elements of this type.
labelUssClassName .unity-base-field__label USS class name of labels in elements of this type.
inputUssClassName .unity-base-field__input USS class name of input elements in elements of this type.
noLabelVariantUssClassName .unity-base-field--no-label USS class name of elements of this type, when there is no label.
labelDraggerVariantUssClassName .unity-base-field__label--with-dragger USS class name of labels in elements of this type, when there is a dragger attached on them.
mixedValueLabelUssClassName .unity-base-field__label--mixed-value USS class name of elements that show mixed values
alignedFieldUssClassName .unity-base-field__aligned USS class name of elements that are aligned in a inspector element
disabledUssClassName .unity-disabled USS class name of local disabled elements.

Additional resources

UXML element DoubleField
UXML element EnumField