UXML element ListView

A ListView is a vertically scrollable area that links to and displays a list of items.

Note: The horizontal and vertical Scroller elements are standard UI Toolkit Scrollers.

Create a ListView

You can create a ListView with UI Builder, UXML, and C#. The following C# example creates a ListView:

var listView = new ListView();

ListView versus ScrollView

You can use a ScrollView control to create the same functionalities as using a ListView. However, a ListView is more efficient than a ScrollView when you do the following:

• Populate list items
• Manage item height
• Bind and unbind to objects
• Instantiate the number of visual elements required to fill a page
• Recycle visual elements to optimize memory handling

Refresh the collection view

To refresh the collection view, in general, call the RefreshItems or RefreshItem method. However, in the following cases, call Rebuild instead to refresh the collection view:

• You change the type of the data source, such as changing from a List<float> to a List<Vector3>.
• You make changes to makeItem or destroyItem.

Note: If you call Rebuild, the collection view is completely rebuilt, which can be expensive. If you call RefreshItems or RefreshItem, the collection view is only refreshed, which is less expensive.

Set item height

To change how item height is used to drive content, use the VirtualizationMethod:

• VirtualizationMethod.FixedHeight sets all items to the same height.
• VirtualizationMethod.DynamicHeight allows items to have varying heights.

Control the scroll speed

The ListView has a built-in child ScrollView element that lets users scroll through the list. You can control the speed of the scroll by overriding the mouseWheelScrollSize, horizontalPageSize, and verticalPageSize properties of the ScrollView with C#.

Implement drag-and-drop operations for ListView

Drag-and-drop is a common feature in UI design. To implement the drag-and-drop operations, override the following methods:

• To enable dragging items, override canStartDrag.
• To set which items are dragged, override setupDragAndDrop.
• To get item status changes, override dragAndDropUpdate. You can perform certain actions based on the drag position or other conditions.
• To control the drag-and-drop behavior, override handleDrop.

During the drag-and-drop operation, you can enable the reordering of items by dragging. To enable, set the reorderable attribute to true in UI Builder, UXML, and C#.

Refer to Create a drag-and-drop list and tree views between windows for an example.

示例

The following UXML example creates a ListView:

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

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

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

To try this example live in Unity, go to Window > UI Toolkit > Samples. ​ For more examples, refer to the following:

• Create list and tree views: Use ListView, TreeView, MultiColumnListView, and MultiColumnTreeView to create list and tree views.
• Create a complex list view: Use ListView to create a custom Editor window with a list of characters.
• Bind to a list with ListView: Create a list of toggles and bind the list to an underlying list of GameSwitch objects.
• Create a drag-and-drop list and tree views between windows: Use ListView, TreeView, and MultiColumnListView to create a drag-and-drop UI between windows.

C# base class and namespace

C# class: ListView
Namespace: UnityEngine.UIElements
Base class: BaseListView

Member UXML attributes

This element has the following member attributes:

名称	类型	描述
item-template	UIElements.VisualTreeAsset	A UXML template that constructs each recycled and rebound element within the list. This template is designed to replace the makeItem definition. You can use it along with BaseListView.bindingSourceSelectionMode and bindings to have a completely codeless workflow.

Inherited UXML attributes

This element inherits the following attributes from its base class:

名称	类型	描述
allow-add	boolean	This property allows the user to allow or block the addition of an item when clicking on the Add Button. It must return true or false. If the callback is not set to false, any Add operation will be allowed.
allow-remove	boolean	This property allows the user to allow or block the removal of an item when clicking on the Remove Button. It must return true or false. If the property is not set to false, any Remove operation will be allowed.
binding-path	string	Path of the target property to be bound.
binding-source-selection-mode	UIElements.BindingSourceSelectionMode	This property controls whether every element in the list will get its data source setup automatically to the correct item in the collection’s source. When set to AutoAssign, the bind callbacks don’t need to be specified, since bindings can be used to fill the elements.
fixed-item-height	float	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.
header-title	string	This property controls the text of the foldout header when using showFoldoutHeader. If the makeHeader callback is set, this property gets overridden and the title is not shown.
reorder-mode	UIElements.ListViewReorderMode	This property controls the drag and drop mode for the list view. The default value is Simple. When this property is set to Animated, Unity adds drag handles in front of every item and the drag and drop manipulation pushes items with an animation when the reordering happens. Multiple item reordering is only supported with the Simple drag mode.
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-add-remove-footer	boolean	This property controls whether a footer will be added to the list view. The default value is false. When this property is set to true, Unity adds a footer under the scroll view. This footer contains two buttons: A “+” button. When clicked, it adds a single item at the end of the list view. A “-” button. When clicked, it removes all selected items, or the last item if none are selected. If the makeFooter callback is set, it will override this property.
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.
show-bound-collection-size	boolean	This property controls whether the list view displays the collection size (number of items). The default value is true. When this property is set to true, Unity displays the collection size as the first item in the list, but does not make it an actual list item that is part of the list index. If you query for list index 0, Unity returns the first real list item, and not the collection size. If showFoldoutHeader is set to true, the collection size field is included in the header instead. You can use this property to debug a ListView because the property indicates whether the data source is linked correctly. In production, the collection size rarely displays as a line item in a ListView. SA: UnityEditor.UIElements.BindingExtensions.Bind
show-foldout-header	boolean	This property controls whether the list view displays a header, in the form of a foldout that can be expanded or collapsed. The default value is false. When this property is set to true, Unity adds a foldout in the hierarchy of the list view and moves the scroll view inside that newly created foldout. You can change the text of this foldout with headerTitle property on the ListView. If showBoundCollectionSize is set to true, the header includes a TextField to control the array size, instead of using the field as part of the list. If the makeHeader callback is set, no Foldout is shown.
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:

名称	类型	描述
content-container	string	Child elements are added to it, usually this is the same as the element itself.
data-source	Object	Assigns a data source to this VisualElement which overrides any inherited data source. This data source is inherited by all children.
data-source-path	string	Path from the data source to the value.
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, such as tree expanded states, scroll position, or zoom level. This key is used to save and load the view data from the view data store. If you don’t set this key, the persistence is disabled for the associated VisualElement. For more information, refer to View data persistence.

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-list-view	The USS class name for ListView elements. Unity adds this USS class to every instance of the ListView element. Any styling applied to this class affects every ListView located beside, or below the stylesheet in the visual tree.
itemUssClassName	.unity-list-view__item	The USS class name of item elements in ListView elements. Unity adds this USS class to every item element the ListView contains. Any styling applied to this class affects every item element located beside, or below the stylesheet in the visual tree.
emptyLabelUssClassName	.unity-list-view__empty-label	The USS class name for label displayed when ListView is empty. Unity adds this USS class to the label displayed if the ListView is empty. Any styling applied to this class affects every empty label located beside, or below the stylesheet in the visual tree.
reorderableUssClassName	.unity-list-view__reorderable	The USS class name for reorderable animated ListView elements. Unity adds this USS class to every instance of the ListView element when reorderMode is set to Animated. Any styling applied to this class affects every ListView located beside, or below the stylesheet in the visual tree.
reorderableItemUssClassName	.unity-list-view__reorderable-item	The USS class name for item elements in reorderable animated ListView. Unity adds this USS class to every element in the ListView when reorderMode is set to Animated. Any styling applied to this class affects every element located beside, or below the stylesheet in the visual tree.
reorderableItemContainerUssClassName	.unity-list-view__reorderable-item__container	The USS class name for item container in reorderable animated ListView. Unity adds this USS class to every item container in the ListView when reorderMode is set to Animated. Any styling applied to this class affects every item container located beside, or below the stylesheet in the visual tree.
reorderableItemHandleUssClassName	.unity-list-view__reorderable-handle	The USS class name for drag handle in reorderable animated ListView. Unity adds this USS class to drag handles in the ListView when reorderMode is set to Animated. Any styling applied to this class affects every drag handle located beside, or below the stylesheet in the visual tree.
reorderableItemHandleBarUssClassName	.unity-list-view__reorderable-handle-bar	The USS class name for drag handle bar in reorderable animated ListView. Unity adds this USS class to every drag handle bar in the ListView when reorderMode is set to Animated. Any styling applied to this class affects every drag handle bar located beside, or below the stylesheet in the visual tree.
footerUssClassName	.unity-list-view__footer	The USS class name for the footer of the ListView. Unity adds this USS class to the footer element in the ListView. Any styling applied to this class affects every ListView located beside, or below the stylesheet in the visual tree.
foldoutHeaderUssClassName	.unity-list-view__foldout-header	The USS class name for the foldout header of the ListView. Unity adds this USS class to the foldout element in the ListView. Any styling applied to this class affects every foldout located beside, or below the stylesheet in the visual tree.
arraySizeFieldUssClassName	.unity-list-view__size-field	The USS class name for the size field of the ListView when foldout header is enabled. Unity adds this USS class to the size field element in the ListView when showFoldoutHeader is set to true. Any styling applied to this class affects every size field located beside, or below the stylesheet in the visual tree.
listViewWithHeaderUssClassName	.unity-list-view--with-header	The USS class name for ListView when foldout header is enabled. Unity adds this USS class to ListView when showFoldoutHeader is set to true. Any styling applied to this class affects every list located beside, or below the stylesheet in the visual tree.
listViewWithFooterUssClassName	.unity-list-view--with-footer	The USS class name for ListView when add/remove footer is enabled. Unity adds this USS class to ListView when showAddRemoveFooter is set to true. Any styling applied to this class affects every list located beside, or below the stylesheet in the visual tree.
scrollViewWithFooterUssClassName	.unity-list-view__scroll-view--with-footer	The USS class name for scroll view when add/remove footer is enabled. Unity adds this USS class scroll view of BaseListViewwhen showAddRemoveFooter is set to true. Any styling applied to this class affects every list 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.

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

• MultiColumnListView
• MultiColumnTreeView
• ScrollView
• TreeView