Version: 2022.1
UXML element FloatField
UXML element GradientField

UXML element Foldout

C# class: Foldout
Namespace: UnityEngine.UIElements
Base class: BindableElement

Member attributes

This element has the following member attributes:

Name Type Description
text string This is the text of the toggle’s label.
value boolean This is the state of the Foldout’s toggle. It is true if the Foldout is open and its contents are visible, and false if the Foldout is closed, and its contents are hidden.

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.
focusable boolean True if the element can be focused.
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-foldout The USS class name for Foldout elements.

Unity adds this USS class to every instance of a Foldout. Any styling applied to this class affects every Foldout located beside, or below the stylesheet in the visual tree.
toggleUssClassName .unity-foldout__toggle The USS class name of Toggle sub-elements in Foldout elements.

Unity adds this USS class to the Toggle sub-element of every Foldout. Any styling applied to this class affects every Toggle sub-element located beside, or below the stylesheet in the visual tree.
contentUssClassName .unity-foldout__content The USS class name for the content element in a Foldout.

Unity adds this USS class to the VisualElement that contains the elements to be shown or hidden. Any styling applied to this class affects every foldout container located beside, or below the stylesheet in the visual tree.
inputUssClassName .unity-foldout__input The USS class name for the Label element in a Foldout.

Unity adds this USS class to the VisualElement that contains the Toggle input elements. Any styling applied to this class affects every foldout container located beside, or below the stylesheet in the visual tree.
checkmarkUssClassName .unity-foldout__checkmark The USS class name for the Label element in a Foldout.

Unity adds this USS class to the VisualElement that represents the checkmark of the Toggle sub-element of every Foldout. Any styling applied to this class affects every foldout container located beside, or below the stylesheet in the visual tree.
textUssClassName .unity-foldout__text The USS class name for the Label element in a Foldout.

Unity adds this USS class to the Label in the Toggle sub-element of every Foldout. Any styling applied to this class affects every foldout container located beside, or below the stylesheet in the visual tree.
disabledUssClassName .unity-disabled USS class name of local disabled elements.

You can also use the Matching Selectors section in the Inspector or the UI Toolkit Debugger to see which USS selectors affect the components of the visual elementA node of a visual tree that instantiates or derives from the C# VisualElement class. You can style the look, define the behaviour, and display it on screen as part of the UI. More info
See in Glossary
at every level of its hierarchy.

Create a Foldout

A Foldout has the following elements:

  • Label: A label you can use as the name of the Foldout.
  • Toggle: Click the toggle to expand or collapse the container sub-element. It is styled to look like an arrow rather than the default checkbox. When the container is collapsed, the arrow points right. When the container is expanded, the arrow points down.
  • Container: A container contains the visual elements that you want to show or hide when you toggle the Foldout.

You can add elements to a Foldout’s container, and the show or hide function works automatically.

The following UI(User Interface) Allows a user to interact with your application. Unity currently supports three UI systems. More info
See in Glossary
Document creates a Foldout with two buttons in its container. The two buttons show or hide when you toggle the Foldout.

<ui:UXML xmlns:ui="UnityEngine.UIElements" xmlns:uie="UnityEditor.UIElements" xsi="http://www.w3.org/2001/XMLSchema-instance" engine="UnityEngine.UIElements" editor="UnityEditor.UIElements" noNamespaceSchemaLocation="../../UIElementsSchema/UIElements.xsd" editor-extension-mode="False">
    <ui:Foldout text="Foldout" name="MyFoldout" value="true">
        <ui:Button text="First item" />
        <ui:Button text="Second item" />
    </ui:Foldout>
</ui:UXML>

You can bind a Foldout to a Boolean variable or access its value through the INotifyValueChanged<bool> interface.

Respond to user actions

A Foldout and its Toggle sub-element respond to Change events. The Toggle hides or shows the Foldout container.

Examples

The following C# code snippet creates a Foldout and checks whether the foldout is expanded:

// Create a new foldout, add two elements to it and add it to the container
var cSharpFoldout = new Foldout {text = "Elements"};
cSharpFoldout.Add(new Label("Indented Label"));
cSharpFoldout.Add(new Slider("Indented Slider", 0, 100));
container.Add(cSharpFoldout);

cSharpFoldout.RegisterValueChangedCallback(e =>
{
    // Check whether the foldout is expanded
    if (cSharpFoldout.value)
    {
        Debug.Log("Foldout is expanded");
    }
    else
    {
        Debug.Log("Foldout is collapsed");
    }
});

Additional resource

UXML element FloatField
UXML element GradientField