Class TextArea

A multi-line text input field that allows users to enter and edit longer text content.

Inheritance
object
CallbackEventHandler
Focusable
VisualElement
BaseVisualElement
ExVisualElement
TextArea
Implements
Inherited Members
VisualElement.Focus()
VisualElement.Overlaps(Rect)
VisualElement.ToString()
VisualElement.TryGetBinding(BindingId, out Binding)
VisualElement.TryGetDataSourceContext(BindingId, out DataSourceContext)
VisualElement.TryGetLastBindingToUIResult(in BindingId, out BindingResult)
VisualElement.TryGetLastBindingToSourceResult(in BindingId, out BindingResult)
VisualElement.GetFirstOfType<T>()
VisualElement.GetFirstAncestorOfType<T>()
VisualElement.canGrabFocus
VisualElement.focusController
VisualElement.cacheAsBitmap
CallbackEventHandler.RegisterCallback<TEventType>(EventCallback<TEventType>, TrickleDown)
CallbackEventHandler.RegisterCallbackOnce<TEventType>(EventCallback<TEventType>, TrickleDown)
CallbackEventHandler.RegisterCallback<TEventType, TUserArgsType>(EventCallback<TEventType, TUserArgsType>, TUserArgsType, TrickleDown)
CallbackEventHandler.RegisterCallbackOnce<TEventType, TUserArgsType>(EventCallback<TEventType, TUserArgsType>, TUserArgsType, TrickleDown)
CallbackEventHandler.RegisterCallback<TEventType>(EventCallback<TEventType>, CallbackOptions)
CallbackEventHandler.RegisterCallback<TEventType, TUserArgsType>(EventCallback<TEventType, TUserArgsType>, TUserArgsType, CallbackOptions)
CallbackEventHandler.UnregisterCallback<TEventType>(EventCallback<TEventType>, TrickleDown)
CallbackEventHandler.UnregisterCallback<TEventType>(EventCallback<TEventType>, CallbackOptions)
CallbackEventHandler.UnregisterCallback<TEventType, TUserArgsType>(EventCallback<TEventType, TUserArgsType>, TrickleDown)
CallbackEventHandler.UnregisterCallback<TEventType, TUserArgsType>(EventCallback<TEventType, TUserArgsType>, CallbackOptions)
CallbackEventHandler.NotifyPropertyChanged(in BindingId)
Namespace: Unity.AppUI.UI
Assembly: Unity.AppUI.dll
Syntax
[UxmlElement]
public class TextArea : ExVisualElement, IEventHandler, IResolvedStyle, ITransform, ITransitionAnimations, IExperimentalFeatures, IVisualElementScheduler, IContextOverrideElement, IAdditionalDataHolder, IInputElement<string>, IValidatableElement<string>, INotifyValueChanging<string>, INotifyValueChanged<string>
Remarks

TextArea is a versatile input component that enables users to enter and edit multiple lines of text. It's particularly useful for collecting longer form responses, comments, or any scenario requiring multi-line text input.

The component features a resizable input area, placeholder text support, and various customization options like auto-resize and validation capabilities.

Key features include:

  • Resizable text area with drag handle
  • Auto-resize capability based on content
  • Placeholder text support
  • Read-only mode
  • Maximum length restriction
  • Input validation
  • Submit on Enter functionality
  • Keyboard focus management
Examples

Basic TextArea with placeholder

Creates a simple TextArea with placeholder text and fixed dimensions.

<TextArea placeholder="Enter your message here..." style="height: 100px; width: 300px;" />

Auto-resizing TextArea with validation

Creates a TextArea that automatically resizes and validates input length.

var textArea = new TextArea {
    autoResize = true,
    autoShrink = true,
    placeholder = "Enter at least 10 characters",
    style = { minHeight = 50, width = 300 }
};

textArea.validateValue = (value) => value.Length >= 10;
textArea.RegisterValueChangedCallback(evt => {
Debug.Log($"Text is valid: {!textArea.invalid}");
});

Comment box with submission handling

Creates a comment box that submits on Shift+Enter with character limit.

<TextArea
    placeholder="Write your comment..."
    submit-on-enter="true"
    submit-modifiers="Shift"
    max-length="500"
    style="min-height: 100px; width: 100%" />

Constructors

TextArea()

Default constructor.

Declaration
public TextArea()

TextArea(string)

Construct a TextArea with a predefined text value.

Declaration
public TextArea(string value)
Parameters
Type Name Description
string value

A default text value.
Remarks

No event will be triggered when setting the text value during construction.

Fields

inputUssClassName

The TextArea input styling class.

Declaration
public const string inputUssClassName = "appui-textarea__input"
Field Value
Type Description
string

placeholderUssClassName

The TextArea placeholder styling class.

Declaration
public const string placeholderUssClassName = "appui-textarea__placeholder"
Field Value
Type Description
string

resizeHandleUssClassName

The TextArea resize handle styling class.

Declaration
public const string resizeHandleUssClassName = "appui-textarea__resize-handle"
Field Value
Type Description
string

scrollViewUssClassName

The TextArea input container styling class.

Declaration
public const string scrollViewUssClassName = "appui-textarea__scrollview"
Field Value
Type Description
string

ussClassName

The TextArea main styling class.

Declaration
public const string ussClassName = "appui-textarea"
Field Value
Type Description
string

Properties

autoResize

Automatically resize the TextArea if the content is larger than the current size.

Declaration
[CreateProperty]
[UxmlAttribute]
public bool autoResize { get; set; }
Property Value
Type Description
bool
Remarks

This will only grow the TextArea. It will not shrink it.

If the user manually resizes the TextArea, the auto resize will be disabled.

autoShrink

Whether the TextArea should automatically shrink if the content is smaller than the current size.

Declaration
[CreateProperty]
[UxmlAttribute]
public bool autoShrink { get; set; }
Property Value
Type Description
bool
Remarks

To enable this feature, autoResize must be set to true.

contentContainer

The content container of the TextArea.

Declaration
public override VisualElement contentContainer { get; }
Property Value
Type Description
VisualElement
Overrides

invalid

The invalid state of the TextArea.

Declaration
[CreateProperty]
[UxmlAttribute]
public bool invalid { get; set; }
Property Value
Type Description
bool

isReadOnly

Whether the TextArea is read-only.

Declaration
[CreateProperty]
[UxmlAttribute]
public bool isReadOnly { get; set; }
Property Value
Type Description
bool

maxLength

The maximum length of the TextArea.

Declaration
[CreateProperty]
[UxmlAttribute]
public int maxLength { get; set; }
Property Value
Type Description
int

placeholder

The TextArea placeholder text.

Declaration
[CreateProperty]
[UxmlAttribute]
public string placeholder { get; set; }
Property Value
Type Description
string

submitActionKeyModifier

Whether the submit action should be triggered by using the Action key (Ctrl on Windows, Cmd on Mac) modifier.

Declaration
[CreateProperty]
[UxmlAttribute]
public bool submitActionKeyModifier { get; set; }
Property Value
Type Description
bool

submitModifiers

The modifiers required to submit the TextArea.

Declaration
[CreateProperty]
[UxmlAttribute]
public EventModifiers submitModifiers { get; set; }
Property Value
Type Description
EventModifiers

submitOnEnter

Whether the TextArea should invoke the submitted event when the user presses the Enter key.

Declaration
[CreateProperty]
[UxmlAttribute]
public bool submitOnEnter { get; set; }
Property Value
Type Description
bool

validateValue

The validation function for the TextArea.

Declaration
[CreateProperty]
public Func<string, bool> validateValue { get; set; }
Property Value
Type Description
Func<string, bool>

value

The TextArea value.

Declaration
[CreateProperty]
[UxmlAttribute]
public string value { get; set; }
Property Value
Type Description
string

Methods

SetValueWithoutNotify(string)

Set the TextArea value without notifying the change.

Declaration
public void SetValueWithoutNotify(string newValue)
Parameters
Type Name Description
string newValue

The new value of the TextArea.

Events

submitted

Event triggered when the user presses the Enter key and submitOnEnter is true.

Declaration
public event Action submitted
Event Type
Type Description
Action

Implements

Extension Methods