TreeView

Namespace: Wisej.Web

Assembly: Wisej.Framework (4.1.0.0)

• Control
  • TreeView

Displays a hierarchical collection of labeled items, each represented by a TreeNode.

C#

public class TreeView : Control

VB.NET

Public Class TreeView
    Inherits Control

Constructors

TreeView()

Initializes a new instance of the TreeView class.

Properties

BorderStyle

BorderStyle: Gets or sets the border style of the tree view control. (Default: Solid)

Value: One of the BorderStyle values. The default is Solid.

ButtonAlign 4.1.7+

Nullable<LeftRightAlignment>: Returns or sets the alignment of the plus-sign (+) and minus-sign (-) buttons. (Default: null)

Value: One of the LeftRightAlignment values, or null to use the value defined in the theme. The default is null.

CheckBoxes

Boolean: Returns or sets whether check boxes are displayed next to the tree nodes in the tree view control. Tree nodes may override this property setting the CheckBox property. (Default: False)

Value: true if a check box is displayed next to each tree node in the tree view control; otherwise, false. The default is false.

HideNodeImages

Boolean: Returns or sets whether all the node images are hidden. Tree nodes may override this property setting the HideNodeImage property. (Default: False)

ImageIndex

Int32: Returns or sets the image-list index value of the default image that is displayed by the tree nodes. (Default: -1)

Value: A zero-based index that represents the position of an Image in an ImageList. The default is zero.

Throws:

• ArgumentOutOfRangeException The specified index is less than -1.

ImageKey

String: Returns or sets the key of the default image for each node in the TreeView control when it is in an unselected state. (Default: "")

Value: The key of the default image shown for each node TreeView control when the node is in an unselected state.

ImageList

ImageList: Returns or sets the ImageList that contains the Image objects that are used by the tree nodes. (Default: null)

Value: The ImageList that contains the Image objects that are used by the tree nodes. The default value is null.

Indent

Int32: Returns or sets the distance in pixels to indent each child tree node level. (Default: -1)

Value: The distance, in pixels, to indent each child tree node level. The default value is -1 (uses the value set in the theme.)

Throws:

• ArgumentOutOfRangeException The assigned value is less than -1; or the assigned value is greater than 500.

ItemHeight

Int32: Gets or sets the height of each tree node in the tree view control. When the value is -1, uses the value set in the theme. (Default: -1)

Value: The height, in pixels, of each tree node in the tree view. The default value is -1 (uses the value set in the theme.)

Throws:

• ArgumentOutOfRangeException The assigned value is less than -1; or the assigned value is greater than 500.

LabelEdit

Boolean: Returns or sets whether the label text of the tree nodes can be edited. (Default: False)

Value: true if the label text of the tree nodes can be edited; otherwise, false. The default is false.

Nodes

TreeNodeCollection: Returns the collection of tree nodes that are assigned to the tree view control.

Value: A TreeNodeCollection that represents the tree nodes assigned to the tree view control.

OpenedImageIndex

Int32: Returns or sets the image list index value of the image that is displayed when a TreeNode is expanded. (Default: -1)

Value: A zero-based index value that represents the position of an Image in an ImageList.

Throws:

• ArgumentException The index assigned value is less than -1.

OpenedImageKey

String: Returns or sets the key of the default image shown when a TreeNode is expanded. (Default: "")

Value: The key of the default image shown when a TreeNode is in a selected state.

PathSeparator

String: Returns or sets the delimiter string that the tree node path uses. (Default: "\")

Value: The delimiter string that the tree node FullPath property uses. The default is the backslash character ().

PrefetchItems

Int32: Returns or sets the number of items to prefetch outside of the visible area when VirtualScroll is set to true. The default is 0 (disabled). (Default: 0)

RightClickSelection

Boolean: Returns or sets whether the TreeNode under the pointer gets selected on a right click. (Default: False)

Value: true if a right click selects the target node; otherwise, false. The default is false.

When the right click lands outside of a selected area the selection is not changed regardless of the value of RightClickSelection.

Scrollable

Boolean: Returns or sets whether the tree view control displays scroll bars when they are needed. (Default: True)

Value: true if the tree view control displays scroll bars when they are needed; otherwise, false. The default is true.

SelectedImageIndex

Int32: Returns or sets the image list index value of the image that is displayed when a TreeNode is selected. (Default: -1)

Value: A zero-based index value that represents the position of an Image in an ImageList.

Throws:

• ArgumentException The index assigned value is less than -1.

SelectedImageKey

String: Returns or sets the key of the default image shown when a TreeNode is selected. (Default: "")

Value: The key of the default image shown when a TreeNode is selected.

SelectedNode

TreeNode: Returns or sets the tree node that is currently selected in the tree view control.

Value: The TreeNode that is currently selected in the tree view control.

SelectedNodes

TreeNode[]: Returns or sets the tree nodes that are currently selected in the tree view control. Use this property when the SelectionMode is MultiSimple or MultiExtended.

Value: An array of TreeNode that are currently selected in the tree view control.

SelectionMode

SelectionMode: Returns or sets the method in which items are selected in the TreeView. (Default: One)

Value: One of the SelectionMode values. The default is SelectionMode.One.

ShowNodeToolTips

Boolean: Returns or sets a value indicating ToolTips are shown when the mouse pointer hovers over a TreeNode. (Default: False)

Value: true if ToolTips are shown when the mouse pointer hovers over a TreeNode; otherwise, false. The default is false.

ShowPlusMinus

Boolean: Returns or sets whether plus-sign (+) and minus-sign (-) buttons are displayed next to tree nodes that contain child tree nodes. (Default: True)

Value: true if plus sign and minus sign buttons are displayed next to tree nodes that contain child tree nodes; otherwise, false. The default is true.

ShowRootLines

Boolean: Returns or sets whether the expand/collapse icon is displayed for the root nodes (the firs level nodes). (Default: True)

Value: true to display the expand/collapse icon for the tree nodes that are at the root of the tree view; otherwise, false. The default is true.

The name of this property is kept as-is for compatibility reasons. When set to true (default) it doesn't show any line next to the root nodes or any other node. It shows or hide the expand/collapse icon next to the root nodes.

Sorted

Boolean: Returns or sets whether the tree nodes in the tree view are sorted. (Default: False)

Value: true if the tree nodes in the tree view are sorted; otherwise, false. The default is false.

StateImageList

ImageList: Returns or sets the image list that is used to indicate the state of the TreeView and its nodes. (Default: null)

Value: The ImageList used for indicating the state of the TreeView and its nodes.

Tools

ComponentToolCollection: Returns the instance of ComponentToolCollection associated with this control.

TopNode

TreeNode: Returns or sets the first fully-visible tree node in the tree view control.

Value: A TreeNode that represents the first fully-visible tree node in the tree view control.

TreeViewNodeSorter

IComparer<TreeNode>: Returns or sets the implementation of IComparer to perform a custom sort of the TreeView nodes.

Value: The IComparer to perform the custom sort.

VirtualScroll

Boolean: Enables or disables virtual scrolling for the TreeView. When virtual scrolling is enabled, only the visible nodes are rendered in the browser allowing the TreeView to host virtually unlimited nodes without any performance loss. (Default: False)

When VirtualScroll is set to true, all the nodes must be of the same height, limiting the more flexible HTML rendering in the nodes available when VirtualScroll is off (default).

Setting the property PrefetchItems to a value greater than 0 allows the virtual view to prefetch the specified number of items outside of the visible area to enable smoother scrolling.

Methods

BeginUpdate()

This method has no effect on this control.

ClearSelected()

Unselects all nodes in the TreeView.

CollapseAll()

Collapses all the tree nodes.

Dispose(disposing)

Disposes the control.

Parameter	Type	Description
disposing	Boolean	true when this method is called by the application rather than a finalizer.

EndUpdate()

This method has no effect on this control.

ExpandAll()

Expands all the tree nodes.

GetNodeCount(includeSubTrees)

Retrieves the number of tree nodes, optionally including those in all subtrees, assigned to the tree view control.

Parameter	Type	Description
includeSubTrees	Boolean	true to count the TreeNode items that the subtrees contain; otherwise, false.

Returns: Int32. The number of tree nodes, optionally including those in all subtrees, assigned to the tree view control.

GetSelected(node)

Returns a value indicating whether the specified TreeNode is selected.

Parameter	Type	Description
node	TreeNode	The TreeNode to check.

Returns: Boolean. true if the specified TreeNode is currently selected in the TreeView; otherwise, false.

Throws:

• ArgumentNullException The specified node is null.
• ArgumentException The specified node is currently assigned to another TreeView.

OnAddReferences(items)

Returns a collection of referenced components or collection of components.

Parameter	Type	Description
items	IList

OnAfterCheck(e)

Fires the AfterCheck event.

Parameter	Type	Description
e	TreeViewEventArgs	A TreeViewEventArgs that contains the event data.

OnAfterCollapse(e)

Fires the AfterCollapse event.

Parameter	Type	Description
e	TreeViewEventArgs	A TreeViewEventArgs that contains the event data.

OnAfterExpand(e)

Fires the AfterExpand event.

Parameter	Type	Description
e	TreeViewEventArgs	A TreeViewEventArgs that contains the event data.

OnAfterLabelEdit(e)

Fires the AfterLabelEdit event.

Parameter	Type	Description
e	NodeLabelEditEventArgs	A NodeLabelEditEventArgs that contains the event data.

OnAfterSelect(e)

Fires the AfterSelect event.

Parameter	Type	Description
e	TreeViewEventArgs	A TreeViewEventArgs that contains the event data.

OnBeforeCheck(e)

Fires the BeforeCheck event.

Parameter	Type	Description
e	TreeViewCancelEventArgs	A TreeViewCancelEventArgs that contains the event data.

OnBeforeCollapse(e)

Fires the BeforeCollapse event.

Parameter	Type	Description
e	TreeViewCancelEventArgs	A TreeViewCancelEventArgs that contains the event data.

OnBeforeExpand(e)

Fires the BeforeExpand event.

Parameter	Type	Description
e	TreeViewCancelEventArgs	A TreeViewCancelEventArgs that contains the event data.

OnBeforeLabelEdit(e)

Fires the BeforeLabelEdit event.

Parameter	Type	Description
e	NodeLabelEditEventArgs	A NodeLabelEditEventArgs that contains the event data.

OnBeforeSelect(e)

Fires the BeforeSelect event.

Parameter	Type	Description
e	TreeViewCancelEventArgs	A TreeViewCancelEventArgs that contains the event data.

OnCreateControl()

Creates and register this control and all its children.

OnItemDrag(e)

Deprecated: This method is deprecated. Use OnNodeDrag instead. Fires the ItemDrag event.

Parameter	Type	Description
e	ItemDragEventArgs	An ItemDragEventArgs that contains the event data.

OnNodeDrag(e)

Fires the NodeDrag event.

Parameter	Type	Description
e	TreeViewNodeDragEventArgs	An TreeViewNodeDragEventArgs that contains the event data.

OnNodeMouseClick(e)

Fires the NodeMouseClick event.

Parameter	Type	Description
e	TreeNodeMouseClickEventArgs	A TreeNodeMouseClickEventArgs that contains the event data.

OnNodeMouseDoubleClick(e)

Fires the NodeMouseDoubleClick event.

Parameter	Type	Description
e	TreeNodeMouseClickEventArgs	A TreeNodeMouseClickEventArgs that contains the event data.

OnNodeMouseHover(e)

Fires the NodeMouseHover event.

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

OnNodeMouseLeave(e)

Fires the NodeMouseLeave event.

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

OnToolClick(e)

Fires the ToolClick event.

Parameter	Type	Description
e	ToolClickEventArgs	A ToolClickEventArgs that contains the event data.

OnWebEvent(e)

Processes the event from the client.

Parameter	Type	Description
e	WisejEventArgs	Event arguments.

OnWebRender(config)

Renders the client component.

Parameter	Type	Description
config	Object	Dynamic configuration object.

OnWebUpdate(state)

Updates the client component using the state information.

Parameter	Type	Description
state	Object	Dynamic state object.

SetSelected(node, selected)

Selects or clears the selection for the specified TreeNode in a TreeView.

Parameter	Type	Description
node	TreeNode	The TreeNode to select.
selected	Boolean	True to select the specified TreeNode, otherwise false to deselect it.

Throws:

• ArgumentNullException The specified node is null.
• ArgumentException The specified node is currently assigned to another TreeView.
• InvalidOperationException The SelectionMode property is set to None.

Sort()

Sorts the items in TreeView control.

Events

AfterCheck

TreeViewEventHandler Occurs after the tree node check box is checked.

AfterCollapse

TreeViewEventHandler Occurs after the tree node is collapsed.

AfterExpand

TreeViewEventHandler Occurs after the tree node is expanded.

AfterLabelEdit

NodeLabelEditEventHandler Occurs after the tree node label text is edited.

AfterSelect

TreeViewEventHandler Occurs after the tree node is selected.

BeforeCheck

TreeViewCancelEventHandler Occurs before the tree node check box is checked.

BeforeCollapse

TreeViewCancelEventHandler Occurs before the tree node is collapsed.

BeforeExpand

TreeViewCancelEventHandler Occurs before the tree node is expanded.

BeforeLabelEdit

NodeLabelEditEventHandler Occurs before the tree node label text is edited.

BeforeSelect

TreeViewCancelEventHandler Occurs before the tree node is selected.

ItemDrag

Deprecated: This event is deprecated. Use NodeDrag instead. ItemDragEventHandler Fired when the user begins dragging a node.

NodeDrag

TreeViewNodeDragEventHandler Fired when the user begins dragging a node.

NodeMouseClick

TreeNodeMouseClickEventHandler Fired when the user clicks a TreeNode with the mouse.

NodeMouseDoubleClick

TreeNodeMouseClickEventHandler Fired when the user double-clicks a TreeNode with the mouse.

NodeMouseHover

TreeNodeMouseHoverEventHandler Fired when the mouse hovers over a TreeNode.

NodeMouseLeave

TreeNodeMouseHoverEventHandler Fired when the mouse leaves the TreeNode.

ToolClick

ToolClickEventHandler Fired when a ComponentTool is clicked.

Implements

Name	Description
IUserData	Provides access to the UserData and Tag properties associated to the component implementing this interface.
IBindableComponent	Bindable components implement this interface.
IDropTarget	Controls that support drag & drop operations implement this interface.
IWisejComponent	All wisej components implement this interface.
IWisejControl	All wisej controls derived from the Control class must implement this interface.
IWisejSerializable	Allows an object to serialize itself.