C# class: TreeView
Namespace: UnityEngine.UIElements
Base class: BaseTreeView
This element inherits the following attributes from its base class:
| Name | Type | Description |
|---|---|---|
auto-expand |
boolean |
When true, items are automatically expanded when added to the TreeView. |
binding-path |
string |
Path of the target property to be bound. |
fixed-item-height |
int |
The height of a single item in the list, in pixels. This property must be set when using the virtualizationMethod is set to FixedHeight, for the collection view to function. If set when virtualizationMethod is DynamicHeight, it serves as the default height to help calculate the number of items necessary and the scrollable area, before items are laid out. It should be set to the minimum expected height of an item. |
focusable |
boolean |
True if the element can be focused. |
reorderable |
boolean |
Gets or sets a value that indicates whether the user can drag list items to reorder them. The default value is false which allows the user to drag items to and from other views when you implement canStartDrag, setupDragAndDrop, dragAndDropUpdate, and handleDrop. Set this value to true to allow the user to reorder items in the list. |
selection-type |
UIElements.SelectionType |
Controls the selection type. The default value is SelectionType.Single. When you set the collection view to disable selections, any current selection is cleared. |
show-alternating-row-backgrounds |
UIElements.AlternatingRowBackground |
This property controls whether the background colors of collection view rows alternate. Takes a value from the AlternatingRowBackground enum. |
show-border |
boolean |
Enable this property to display a border around the collection view. If set to true, a border appears around the ScrollView that the collection view uses internally. |
tabindex |
int |
An integer used to sort focusables in the focus ring. Must be greater than or equal to zero. |
virtualization-method |
UIElements.CollectionVirtualizationMethod |
The virtualization method to use for this collection when a scroll bar is visible. Takes a value from the CollectionVirtualizationMethod enum.The default value is FixedHeight. When using fixed height, specify the fixedItemHeight property. Fixed height is more performant but offers less flexibility on content. When using DynamicHeight, the collection will wait for the actual height to be computed. Dynamic height is more flexible but less performant. |
This element also inherits the following attributes from VisualElement:
| Name | Type | Description |
|---|---|---|
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(User Interface) Allows a user to interact with your application. Unity currently supports three UI systems. More info See in Glossary. |
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. |
The following table lists all the C# public property names and their related USS selector.
| C# property | USS selector | Description |
|---|---|---|
ussClassName |
.unity-tree-view |
The USS class name for TreeView elements. Unity adds this USS class to every instance of the TreeView element. Any styling applied to this class affects every TreeView located beside, or below the stylesheet in the visual tree. |
itemUssClassName |
.unity-tree-view__item |
The USS class name for TreeView item elements. Unity adds this USS class to every item element of the TreeView. Any styling applied to this class affects every item located beside, or below the stylesheet in the visual tree. |
itemToggleUssClassName |
.unity-tree-view__item-toggle |
The USS class name for TreeView item toggle elements. Unity adds this USS class to every item toggle element of the TreeView. Any styling applied to this class affects every item located beside, or below the stylesheet in the visual tree. |
itemIndentsContainerUssClassName |
.unity-tree-view__item-indents |
The USS class name for TreeView indent container elements. Unity adds this USS class to every indent container element of the TreeView. Any styling applied to this class affects every item located beside, or below the stylesheet in the visual tree. |
itemIndentUssClassName |
.unity-tree-view__item-indent |
The USS class name for TreeView indent element. Unity adds this USS class to every indent element of the TreeView. Any styling applied to this class affects every item located beside, or below the stylesheet in the visual tree. |
itemContentContainerUssClassName |
.unity-tree-view__item-content |
The USS class name for TreeView item container elements. Unity adds this USS class to every item container element of the TreeView. Any styling applied to this class affects every item located beside, or below the stylesheet in the visual tree. |
ussClassName |
.unity-collection-view |
The USS class name for BaseVerticalCollectionView elements. Unity adds this USS class to every instance of the BaseVerticalCollectionView element. Any styling applied to this class affects every BaseVerticalCollectionView located beside, or below the stylesheet in the visual tree. |
borderUssClassName |
.unity-collection-view--with-border |
The USS class name for BaseVerticalCollectionView elements with a border. Unity adds this USS class to an instance of the BaseVerticalCollectionView element if the instance’s BaseVerticalCollectionView.showBorder property is set to true. Any styling applied to this class affects every such BaseVerticalCollectionView located beside, or below the stylesheet in the visual tree. |
itemUssClassName |
.unity-collection-view__item |
The USS class name of item elements in BaseVerticalCollectionView elements. Unity adds this USS class to every item element the BaseVerticalCollectionView contains. Any styling applied to this class affects every item element located beside, or below the stylesheet in the visual tree. |
dragHoverBarUssClassName |
.unity-collection-view__drag-hover-bar |
The USS class name of the drag hover bar. Unity adds this USS class to the bar that appears when the user drags an item in the list. Any styling applied to this class affects every BaseVerticalCollectionView located beside, or below the stylesheet in the visual tree. |
dragHoverMarkerUssClassName |
.unity-collection-view__drag-hover-marker |
The USS class name of the drag hover circular marker used to indicate depth. Unity adds this USS class to the bar that appears when the user drags an item in the list. Any styling applied to this class affects every BaseVerticalCollectionView located beside, or below the stylesheet in the visual tree. |
itemDragHoverUssClassName |
.unity-collection-view__item--drag-hover |
The USS class name applied to an item element on drag hover. Unity adds this USS class to the item element when it’s being dragged. Any styling applied to this class affects every BaseVerticalCollectionView item located beside, or below the stylesheet in the visual tree. |
itemSelectedVariantUssClassName |
.unity-collection-view__item--selected |
The USS class name of selected item elements in the BaseVerticalCollectionView. Unity adds this USS class to every selected element in the BaseVerticalCollectionView. The BaseVerticalCollectionView.selectionType property decides if zero, one, or more elements can be selected. Any styling applied to this class affects every BaseVerticalCollectionView item located beside, or below the stylesheet in the visual tree. |
itemAlternativeBackgroundUssClassName |
.unity-collection-view__item--alternative-background |
The USS class name for odd rows in the BaseVerticalCollectionView. Unity adds this USS class to every odd-numbered item in the BaseVerticalCollectionView when the BaseVerticalCollectionView.showAlternatingRowBackgrounds property is set to ContentOnly or All. When the showAlternatingRowBackgrounds property is set to either of those values, odd-numbered items are displayed with a different background color than even-numbered items. This USS class is used to differentiate odd-numbered items from even-numbered items. When the showAlternatingRowBackgrounds property is set to None, the USS class is not added, and any styling or behavior that relies on it’s invalidated. |
listScrollViewUssClassName |
.unity-collection-view__scroll-view |
The USS class name of the scroll view in the BaseVerticalCollectionView. Unity adds this USS class to the BaseVerticalCollectionView’s scroll view. Any styling applied to this class affects every BaseVerticalCollectionView scroll view located beside, or below the stylesheet in the visual tree. |
disabledUssClassName |
.unity-disabled |
USS class name of local disabled elements. |