UXML element HelpBox

A HelpBox displays a message to the user. You can set the type of message to display, such as a warning or an error. You can also set the message to display as rich text.

Create a HelpBox

You can create a HelpBox with UXML and C#. The following C# example creates a HelpBox with the message “Help text” and the information icon:

HelpBox helpBox = new HelpBox("Help text", HelpBoxMessageType.Info);

示例

The following UXML example creates a HelpBox with a warning message:

[!code-xml[(External/Resources/editor_resources/Assets/Editor Default Resources/UIPackageResources/Snippets/UXML/HelpBoxSnippet.uxml)]

The following C# example illustrates some of the customizable functionalities of the HelpBox:

[!code-cs[(Modules/UIElementsSamplesEditor/Snippets/HelpBoxSnippet.cs#sample)]

To try this example live in Unity, go to Window > UI Toolkit > Samples.

C# base class and namespace

C# class: HelpBox
Namespace: UnityEngine.UIElements
Base class: VisualElement

Member UXML attributes

This element has the following member attributes:

名称	类型	描述
message-type	UIElements.HelpBoxMessageType	The type of message.
text	string	The message text.

Inherited UXML attributes

This element inherits the following attributes from its base class:

名称	类型	描述
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:

名称	类型	描述
content-container	string	Child elements are added to it, usually this is the same as the element itself.
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. This is only supported in the Editor UI.
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	描述
ussClassName	.unity-help-box	The USS class name for Elements of this type.
labelUssClassName	.unity-help-box__label	The USS class name for labels in Elements of this type.
iconUssClassName	.unity-help-box__icon	The USS class name for images in Elements of this type.
iconInfoUssClassName	.unity-help-box__icon--info	The USS class name for the HelpBoxMessageType.Info state in Elements of this type.
iconwarningUssClassName	.unity-help-box__icon--warning	The USS class name for the HelpBoxMessageType.Warning state in Elements of this type.
iconErrorUssClassName	.unity-help-box__icon--error	The USS class name for the HelpBoxMessageType.Error state in Elements of this type.
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 VisualElement at every level of its hierarchy.

其他资源

• Work with text