TreeListBox Class

[TemplatePart(Name = "PART_ScrollViewer", Type = typeof(ScrollViewer))]
public class TreeListBox : ItemsControl

public TreeListBox()

[Browsable(false)]
protected virtual UIAssemblyInfoBase? AssemblyInfo { get; }

Property Value

UIAssemblyInfoBase

public bool AutoExpandItemsOnFilter { get; set; }

Property Value

bool:

true if items that are included by a filter will be made visible; otherwise, false. The default value is false.

public bool CanDragItems { get; set; }

Property Value

bool:

true if dragging of selected items is allowed; otherwise, false.

protected virtual bool CanExpandAll { get; }

Property Value

bool:

true if any expand all operations can occur; otherwise, false. The default value is true.

public bool CanSelectItemOnFocus { get; set; }

Property Value

bool:

true if an item is selected when it receives focus; otherwise, false. The default value is false.

public IDataFilter? DataFilter { get; set; }

Property Value

IDataFilter

public object? EmptyContent { get; set; }

Property Value

object

public DataTemplate? EmptyContentTemplate { get; set; }

Property Value

DataTemplate

public bool HasTreeLines { get; set; }

Property Value

bool:

true if tree lines should be rendered; otherwise, false. The default value is false.

Remarks

Tree lines can't render in PropertyGrid controls.

public double IndentIncrement { get; set; }

Property Value

double:

The default value is 20.0.

public bool IsDataVirtualizationEnabled { get; set; }

Property Value

bool:

true if data virtualization is enabled; otherwise, false. The default value is false.

Remarks

Only set this property to true when using virtualized collections that implement IList. In most scenarios, this data virtualization feature is not needed since UI virtualization is always active in the control.

When the data virtualization feature is enabled, as a query for child items is made, an ITreeItemVirtualPlaceholder will be created for each child item. The only property initially touched on the virtualized collection is Count. Then when an item's UI container is first requested, the ITreeItemVirtualPlaceholder will be used to call into the virtualized collection's indexer and retrieve the real item. This allows for virtualized data retrieval of paged sections as needed, instead of the entire collection at once.

public bool IsEmpty { get; }

Property Value

bool:

true if the control is currently empty (doesn't contain any visible items); otherwise, false. The default value is true.

public bool IsFilterActive { get; set; }

Property Value

bool:

true if a filter is currently active; otherwise, false. The default value is false.

protected virtual bool IsKeyboardFocusWithinContent { get; }

Property Value

bool:

true if keyboard focus is within the content area; otherwise, false.

public bool IsRootItemVisible { get; set; }

Property Value

bool:

true if the RootItem is the sole top-level node item; otherwise, false. The default value is false.

Remarks

When true, the RootItem itself will be the sole top-level node item. When false, the RootItem's children will be the top-level node items.

public TreeListBoxItemAdapter? ItemAdapter { get; set; }

Property Value

TreeListBoxItemAdapter

public TreeMultiDragKind MultiDragKind { get; set; }

Property Value

TreeMultiDragKind:

The default value is None, meaning only single item selections can be dragged when CanDragItems is true.

public TreeMultiSelectionKind MultiSelectionKind { get; set; }

Property Value

TreeMultiSelectionKind:

The default value is Any.

public string PathSeparator { get; set; }

Property Value

string:

The default value is </code>.

public object? RootItem { get; set; }

Property Value

object

Remarks

Set this property instead of ItemsSource.

public object? SelectedItem { get; set; }

Property Value

object

Remarks

This property's setter can be a bottleneck in very large trees where the specified node hasn't yet been exposed to the control by its ancestor nodes all being expanded. In that scenario, a full tree search is required to locate the node.

public ISelectedTreeItemCollection SelectedItems { get; }

Property Value

ISelectedTreeItemCollection

public SelectionMode SelectionMode { get; set; }

Property Value

SelectionMode:

The default value is Single.

public double TopLevelIndent { get; set; }

Property Value

double:

The default value is 20.0.

Remarks

When top-level items aren't expandable, set this property to 0 to reclaim the space that would have been used by the expander.

protected override Size ArrangeOverride(Size finalSize)

Parameter	Type	Description
finalSize	Size

Returns

Size:

The size of the control.

public bool BringItemIntoView(object item)

Parameter	Type	Description
item	object	The node whose container needs to scroll into view.

Returns

bool:

true if the node's container was brought into view; otherwise, false.

Remarks

This method can be a bottleneck in very large trees where the specified node hasn't yet been exposed to the control by its ancestor nodes all being expanded. In that scenario, a full tree search is required to locate the node. For that case, it is recommended to use the BringItemIntoViewByFullPath(string) method that searches by full path instead, since that can be much faster.

public bool BringItemIntoViewByFullPath(string fullPath)

Parameter	Type	Description
fullPath	string	The full path to the item whose container needs to scroll into view.

Returns

bool:

true if the item's container was brought into view; otherwise, false.

Remarks

This method requires that the ItemAdapter supplies a path for each item.

protected override void ClearContainerForItemOverride(DependencyObject element, object item)

Parameter	Type	Description
element	DependencyObject	The container element.
item	object	The item.

public void CollapseAll()

public IDisposable CreateSelectionBatch()

Returns

IDisposable:

The IDisposable that was created.

public void ExpandAll()

public void FocusItem(object item)

Parameter	Type	Description
item	object	The node whose container should be focused.

Remarks

This method can be a bottleneck in very large trees where the specified node hasn't yet been exposed to the control by its ancestor nodes all being expanded. In that scenario, a full tree search is required to locate the node. For that case, it is recommended to use the FocusItemByFullPath(string) method that searches by full path instead, since that can be much faster.

public void FocusItemByFullPath(string fullPath)

Parameter	Type	Description
fullPath	string	The full path to the node whose container should be focused.

Remarks

This method requires that the ItemAdapter supplies a path for each item.

protected override DependencyObject GetContainerForItemOverride()

Returns

DependencyObject:

The element that is used to display the given item.

public string? GetFullPath(object item)

Parameter	Type	Description
item	object	The item to examine.

Returns

string

public static bool GetIsSelectionActive(TreeListBox obj)

Parameter	Type	Description
obj	TreeListBox	The object from which the property value is read.

Returns

bool

public object? GetItemByFullPath(string fullPath)

Parameter	Type	Description
fullPath	string	The full path to the item.

Returns

object

public ITreeItemNavigator? GetItemNavigator(object item)

Parameter	Type	Description
item	object	The visible item to examine.

Returns

ITreeItemNavigator

Remarks

This navigator can be used to navigate the item tree. No navigator will be returned if the item is not a visible item in this control.

public void InvalidateChildren(object item)

Parameter	Type	Description
item	object	The item to examine.

protected override bool IsItemItsOwnContainerOverride(object item)

Parameter	Type	Description
item	object	The item to check.

Returns

bool:

true if the item is (or is eligible to be) its own container; otherwise, false.

public override void OnApplyTemplate()

protected override AutomationPeer OnCreateAutomationPeer()

Returns

AutomationPeer:

The type-specific AutomationPeer implementation.

protected override void OnDragEnter(DragEventArgs e)

Parameter	Type	Description
e	DragEventArgs	The DragEventArgs that contains the event data.

protected override void OnDragLeave(DragEventArgs e)

Parameter	Type	Description
e	DragEventArgs	The DragEventArgs that contains the event data.

protected override void OnDragOver(DragEventArgs e)

Parameter	Type	Description
e	DragEventArgs	The DragEventArgs that contains the event data.

protected override void OnDrop(DragEventArgs e)

Parameter	Type	Description
e	DragEventArgs	The DragEventArgs that contains the event data.

protected virtual void OnFilterApplied(RoutedEventArgs e)

Parameter	Type	Description
e	RoutedEventArgs	The event data.

Remarks

This method has no default implementation. Because an intermediate class in the inheritance might implement this method, we recommend that you call the base implementation in your implementation.

protected override void OnGotKeyboardFocus(KeyboardFocusChangedEventArgs e)

Parameter	Type	Description
e	KeyboardFocusChangedEventArgs	The KeyboardFocusChangedEventArgs that contains the event data.

protected override void OnIsKeyboardFocusWithinChanged(DependencyPropertyChangedEventArgs e)

Parameter	Type	Description
e	DependencyPropertyChangedEventArgs	A System.Windows.DependencyPropertyChangedEventArgs that contains the event data.

protected virtual void OnIsRootItemVisibleChanged(RoutedEventArgs e)

Parameter	Type	Description
e	RoutedEventArgs	The event data.

Remarks

This method has no default implementation. Because an intermediate class in the inheritance might implement this method, we recommend that you call the base implementation in your implementation.

protected virtual void OnItemCollapsed(TreeListBoxItemExpansionEventArgs e)

Parameter	Type	Description
e	TreeListBoxItemExpansionEventArgs	The event data.

Remarks

This method has no default implementation. Because an intermediate class in the inheritance might implement this method, we recommend that you call the base implementation in your implementation.

protected virtual void OnItemCollapsing(TreeListBoxItemExpansionEventArgs e)

Parameter	Type	Description
e	TreeListBoxItemExpansionEventArgs	The event data.

Remarks

This method has no default implementation. Because an intermediate class in the inheritance might implement this method, we recommend that you call the base implementation in your implementation.

protected virtual void OnItemDefaultActionExecuting(TreeListBoxItemEventArgs e)

Parameter	Type	Description
e	TreeListBoxItemEventArgs	The event data.

Remarks

This method has no default implementation. Because an intermediate class in the inheritance might implement this method, we recommend that you call the base implementation in your implementation.

protected virtual void OnItemExpanded(TreeListBoxItemExpansionEventArgs e)

Parameter	Type	Description
e	TreeListBoxItemExpansionEventArgs	The event data.

Remarks

This method has no default implementation. Because an intermediate class in the inheritance might implement this method, we recommend that you call the base implementation in your implementation.

protected virtual void OnItemExpanding(TreeListBoxItemExpansionEventArgs e)

Parameter	Type	Description
e	TreeListBoxItemExpansionEventArgs	The event data.

Remarks

This method has no default implementation. Because an intermediate class in the inheritance might implement this method, we recommend that you call the base implementation in your implementation.

protected virtual void OnItemMenuRequested(TreeListBoxItemMenuEventArgs e)

Parameter	Type	Description
e	TreeListBoxItemMenuEventArgs	The event data.

Remarks

This method has no default implementation. Because an intermediate class in the inheritance might implement this method, we recommend that you call the base implementation in your implementation.

protected virtual void OnItemSelecting(TreeListBoxItemEventArgs e)

Parameter	Type	Description
e	TreeListBoxItemEventArgs	The event data.

Remarks

This method has no default implementation. Because an intermediate class in the inheritance might implement this method, we recommend that you call the base implementation in your implementation.

protected override void OnItemsSourceChanged(IEnumerable oldValue, IEnumerable newValue)

Parameter	Type	Description
oldValue	IEnumerable	Old value of the ItemsSource property.
newValue	IEnumerable	New value of the ItemsSource property.

protected override void OnKeyDown(KeyEventArgs e)

Parameter	Type	Description
e	KeyEventArgs	Information about the event.

protected virtual void OnRootItemChanged(RoutedEventArgs e)

Parameter	Type	Description
e	RoutedEventArgs	The event data.

Remarks

This method has no default implementation. Because an intermediate class in the inheritance might implement this method, we recommend that you call the base implementation in your implementation.

protected virtual void OnScrollViewerScrollChanged(ScrollChangedEventArgs e)

Parameter	Type	Description
e	ScrollChangedEventArgs	The event data.

protected virtual void OnSelectionChanged(SelectionChangedEventArgs e)

Parameter	Type	Description
e	SelectionChangedEventArgs	The event data.

Remarks

This method has no default implementation. Because an intermediate class in the inheritance might implement this method, we recommend that you call the base implementation in your implementation.

protected override void PrepareContainerForItemOverride(DependencyObject element, object item)

Parameter	Type	Description
element	DependencyObject	Element used to display the specified item.
item	object	Specified item.

protected virtual void ProcessKeyDown(KeyEventArgs e)

Parameter	Type	Description
e	KeyEventArgs	The event data.

public virtual bool SelectItemByFullPath(string fullPath)

Parameter	Type	Description
fullPath	string	The full path to the node whose container should be selected.

Returns

bool:

true if a node was selected; otherwise, false.

Remarks

This method requires that the ItemAdapter supplies a path for each item.

public event RoutedEventHandler FilterApplied

Event Type

RoutedEventHandler

public event RoutedEventHandler IsRootItemVisibleChanged

Event Type

RoutedEventHandler

public event EventHandler<TreeListBoxItemExpansionEventArgs> ItemCollapsed

Event Type

EventHandler<TreeListBoxItemExpansionEventArgs>

public event EventHandler<TreeListBoxItemExpansionEventArgs> ItemCollapsing

Event Type

EventHandler<TreeListBoxItemExpansionEventArgs>

Remarks

Set the event argument's Cancel property to true to prevent the collapse.

public event EventHandler<TreeListBoxItemEventArgs> ItemDefaultActionExecuting

Event Type

EventHandler<TreeListBoxItemEventArgs>

Remarks

Set the event argument's Cancel property to true to prevent a default action from executing, which could be executing a DefaultActionCommand or toggling the item's expansion.

public event EventHandler<TreeListBoxItemExpansionEventArgs> ItemExpanded

Event Type

EventHandler<TreeListBoxItemExpansionEventArgs>

public event EventHandler<TreeListBoxItemExpansionEventArgs> ItemExpanding

Event Type

EventHandler<TreeListBoxItemExpansionEventArgs>

Remarks

Set the event argument's Cancel property to true to prevent the expansion.

public event EventHandler<TreeListBoxItemMenuEventArgs> ItemMenuRequested

Event Type

EventHandler<TreeListBoxItemMenuEventArgs>

public event EventHandler<TreeListBoxItemEventArgs> ItemSelecting

Event Type

EventHandler<TreeListBoxItemEventArgs>

Remarks

Set the event argument's Cancel property to true to prevent the selection.

public event RoutedEventHandler RootItemChanged

Event Type

RoutedEventHandler

public event SelectionChangedEventHandler SelectionChanged

Event Type

SelectionChangedEventHandler

public static readonly DependencyProperty AutoExpandItemsOnFilterProperty

public static readonly DependencyProperty CanDragItemsProperty

public static readonly DependencyProperty CanSelectItemOnFocusProperty

public static readonly DependencyProperty DataFilterProperty

public static readonly DependencyProperty EmptyContentProperty

public static readonly DependencyProperty EmptyContentTemplateProperty

public static readonly RoutedEvent FilterAppliedEvent

public static readonly DependencyProperty HasTreeLinesProperty

public static readonly DependencyProperty IndentIncrementProperty

public static readonly DependencyProperty IsDataVirtualizationEnabledProperty

public static readonly DependencyProperty IsEmptyProperty

public static readonly DependencyProperty IsFilterActiveProperty

public static readonly RoutedEvent IsRootItemVisibleChangedEvent

public static readonly DependencyProperty IsRootItemVisibleProperty

public static readonly DependencyProperty IsSelectionActiveProperty

public static readonly DependencyProperty ItemAdapterProperty

public static readonly RoutedEvent ItemCollapsedEvent

public static readonly RoutedEvent ItemCollapsingEvent

public const string ItemDataFormat = "ActiproSoftware.TreeListBox.Items"

public static readonly RoutedEvent ItemDefaultActionExecutingEvent

public static readonly RoutedEvent ItemExpandedEvent

public static readonly RoutedEvent ItemExpandingEvent

public static readonly RoutedEvent ItemMenuRequestedEvent

public static readonly RoutedEvent ItemSelectingEvent

public static readonly DependencyProperty MultiDragKindProperty

public static readonly DependencyProperty MultiSelectionKindProperty

public static readonly DependencyProperty PathSeparatorProperty

public static readonly RoutedEvent RootItemChangedEvent

public static readonly DependencyProperty RootItemProperty

public static readonly DependencyProperty SelectedItemProperty

public static readonly RoutedEvent SelectionChangedEvent

public static readonly DependencyProperty SelectionModeProperty

public static readonly DependencyProperty TopLevelIndentProperty