# TreeView Namespace: **Wisej.Web** Assembly: **Wisej.Framework** (4.0.0.0) * [Control](https://docs.wisej.com/api/wisej.web/general/control) * [TreeView](https://docs.wisej.com/api/wisej.web/lists-and-grids/treeview) Displays a hierarchical collection of labeled items, each represented by a [TreeNode](https://docs.wisej.com/api/wisej.web/lists-and-grids/treeview/wisej.web.treenode). {% tabs %} {% tab title="C#" %} ```csharp public class TreeView : Control ``` {% endtab %} {% tab title="VB.NET" %} ```visual-basic Public Class TreeView Inherits Control ``` {% endtab %} {% endtabs %} ## Constructors ### ![](https://1075938901-files.gitbook.io/~/files/v0/b/gitbook-x-prod.appspot.com/o/spaces%2F2HvlWXJQMV7DxhGzw7Y1%2Fuploads%2Fgit-blob-2389c55cd19719a73a5ae98e1528c8dc8525cc35%2Finstance.png?alt=media) TreeView() Initializes a new instance of the [TreeView](https://docs.wisej.com/api/wisej.web/lists-and-grids/treeview) class. ## Properties ### ![](https://1075938901-files.gitbook.io/~/files/v0/b/gitbook-x-prod.appspot.com/o/spaces%2F2HvlWXJQMV7DxhGzw7Y1%2Fuploads%2Fgit-blob-2389c55cd19719a73a5ae98e1528c8dc8525cc35%2Finstance.png?alt=media) BorderStyle [BorderStyle](https://docs.wisej.com/api/wisej.web/enumerations/wisej.web.borderstyle): Gets or sets the border style of the tree view control. (Default: `Solid`) ### ![](https://1075938901-files.gitbook.io/~/files/v0/b/gitbook-x-prod.appspot.com/o/spaces%2F2HvlWXJQMV7DxhGzw7Y1%2Fuploads%2Fgit-blob-2389c55cd19719a73a5ae98e1528c8dc8525cc35%2Finstance.png?alt=media) CheckBoxes [Boolean](https://docs.microsoft.com/dotnet/api/system.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](https://docs.wisej.com/api/wisej.web/lists-and-grids/wisej.web.treenode#checkbox) property. (Default: `False`) ### ![](https://1075938901-files.gitbook.io/~/files/v0/b/gitbook-x-prod.appspot.com/o/spaces%2F2HvlWXJQMV7DxhGzw7Y1%2Fuploads%2Fgit-blob-2389c55cd19719a73a5ae98e1528c8dc8525cc35%2Finstance.png?alt=media) HideNodeImages [Boolean](https://docs.microsoft.com/dotnet/api/system.boolean): Returns or sets whether all the node images are hidden. Tree nodes may override this property setting the [HideNodeImage](https://docs.wisej.com/api/wisej.web/lists-and-grids/wisej.web.treenode#hidenodeimage) property. (Default: `False`) ### ![](https://1075938901-files.gitbook.io/~/files/v0/b/gitbook-x-prod.appspot.com/o/spaces%2F2HvlWXJQMV7DxhGzw7Y1%2Fuploads%2Fgit-blob-2389c55cd19719a73a5ae98e1528c8dc8525cc35%2Finstance.png?alt=media) ImageIndex [Int32](https://docs.microsoft.com/dotnet/api/system.int32): Returns or sets the image-list index value of the default image that is displayed by the tree nodes. (Default: `-1`) **Throws:** * [ArgumentOutOfRangeException](https://docs.microsoft.com/dotnet/api/system.argumentoutofrangeexception)\ The specified index is less than -1. ### ![](https://1075938901-files.gitbook.io/~/files/v0/b/gitbook-x-prod.appspot.com/o/spaces%2F2HvlWXJQMV7DxhGzw7Y1%2Fuploads%2Fgit-blob-2389c55cd19719a73a5ae98e1528c8dc8525cc35%2Finstance.png?alt=media) ImageKey [String](https://docs.microsoft.com/dotnet/api/system.string): Returns or sets the key of the default image for each node in the [TreeView](https://docs.wisej.com/api/wisej.web/lists-and-grids/treeview) control when it is in an unselected state. (Default: `""`) ### ![](https://1075938901-files.gitbook.io/~/files/v0/b/gitbook-x-prod.appspot.com/o/spaces%2F2HvlWXJQMV7DxhGzw7Y1%2Fuploads%2Fgit-blob-2389c55cd19719a73a5ae98e1528c8dc8525cc35%2Finstance.png?alt=media) ImageList [ImageList](https://docs.wisej.com/api/wisej.web/content/imagelist): Returns or sets the [ImageList](https://docs.wisej.com/api/wisej.web/content/imagelist) that contains the [Image](https://docs.microsoft.com/dotnet/api/system.drawing.image) objects that are used by the tree nodes. (Default: `null`) ### ![](https://1075938901-files.gitbook.io/~/files/v0/b/gitbook-x-prod.appspot.com/o/spaces%2F2HvlWXJQMV7DxhGzw7Y1%2Fuploads%2Fgit-blob-2389c55cd19719a73a5ae98e1528c8dc8525cc35%2Finstance.png?alt=media) Indent [Int32](https://docs.microsoft.com/dotnet/api/system.int32): Returns or sets the distance in pixels to indent each child tree node level. (Default: `-1`) **Throws:** * [ArgumentOutOfRangeException](https://docs.microsoft.com/dotnet/api/system.argumentoutofrangeexception)\ The assigned value is less than -1; or the assigned value is greater than 500. ### ![](https://1075938901-files.gitbook.io/~/files/v0/b/gitbook-x-prod.appspot.com/o/spaces%2F2HvlWXJQMV7DxhGzw7Y1%2Fuploads%2Fgit-blob-2389c55cd19719a73a5ae98e1528c8dc8525cc35%2Finstance.png?alt=media) ItemHeight [Int32](https://docs.microsoft.com/dotnet/api/system.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`) **Throws:** * [ArgumentOutOfRangeException](https://docs.microsoft.com/dotnet/api/system.argumentoutofrangeexception)\ The assigned value is less than -1; or the assigned value is greater than 500. ### ![](https://1075938901-files.gitbook.io/~/files/v0/b/gitbook-x-prod.appspot.com/o/spaces%2F2HvlWXJQMV7DxhGzw7Y1%2Fuploads%2Fgit-blob-2389c55cd19719a73a5ae98e1528c8dc8525cc35%2Finstance.png?alt=media) LabelEdit [Boolean](https://docs.microsoft.com/dotnet/api/system.boolean): Returns or sets whether the label text of the tree nodes can be edited. (Default: `False`) ### ![](https://1075938901-files.gitbook.io/~/files/v0/b/gitbook-x-prod.appspot.com/o/spaces%2F2HvlWXJQMV7DxhGzw7Y1%2Fuploads%2Fgit-blob-2389c55cd19719a73a5ae98e1528c8dc8525cc35%2Finstance.png?alt=media) Nodes [TreeNodeCollection](https://docs.wisej.com/api/wisej.web/lists-and-grids/treeview/wisej.web.treenodecollection): Returns the collection of tree nodes that are assigned to the tree view control. ### ![](https://1075938901-files.gitbook.io/~/files/v0/b/gitbook-x-prod.appspot.com/o/spaces%2F2HvlWXJQMV7DxhGzw7Y1%2Fuploads%2Fgit-blob-2389c55cd19719a73a5ae98e1528c8dc8525cc35%2Finstance.png?alt=media) OpenedImageIndex [Int32](https://docs.microsoft.com/dotnet/api/system.int32): Returns or sets the image list index value of the image that is displayed when a [TreeNode](https://docs.wisej.com/api/wisej.web/lists-and-grids/treeview/wisej.web.treenode) is expanded. (Default: `-1`) **Throws:** * [ArgumentException](https://docs.microsoft.com/dotnet/api/system.argumentexception)\ The index assigned value is less than -1. ### ![](https://1075938901-files.gitbook.io/~/files/v0/b/gitbook-x-prod.appspot.com/o/spaces%2F2HvlWXJQMV7DxhGzw7Y1%2Fuploads%2Fgit-blob-2389c55cd19719a73a5ae98e1528c8dc8525cc35%2Finstance.png?alt=media) OpenedImageKey [String](https://docs.microsoft.com/dotnet/api/system.string): Returns or sets the key of the default image shown when a [TreeNode](https://docs.wisej.com/api/wisej.web/lists-and-grids/treeview/wisej.web.treenode) is expanded. (Default: `""`) ### ![](https://1075938901-files.gitbook.io/~/files/v0/b/gitbook-x-prod.appspot.com/o/spaces%2F2HvlWXJQMV7DxhGzw7Y1%2Fuploads%2Fgit-blob-2389c55cd19719a73a5ae98e1528c8dc8525cc35%2Finstance.png?alt=media) PathSeparator [String](https://docs.microsoft.com/dotnet/api/system.string): Returns or sets the delimiter string that the tree node path uses. (Default: `"\"`) ### ![](https://1075938901-files.gitbook.io/~/files/v0/b/gitbook-x-prod.appspot.com/o/spaces%2F2HvlWXJQMV7DxhGzw7Y1%2Fuploads%2Fgit-blob-2389c55cd19719a73a5ae98e1528c8dc8525cc35%2Finstance.png?alt=media) PrefetchItems [Int32](https://docs.microsoft.com/dotnet/api/system.int32): Returns or sets the number of items to prefetch outside of the visible area when [VirtualScroll](#virtualscroll) is set to true. The default is 0 (disabled). (Default: `0`) ### ![](https://1075938901-files.gitbook.io/~/files/v0/b/gitbook-x-prod.appspot.com/o/spaces%2F2HvlWXJQMV7DxhGzw7Y1%2Fuploads%2Fgit-blob-2389c55cd19719a73a5ae98e1528c8dc8525cc35%2Finstance.png?alt=media) RightClickSelection [Boolean](https://docs.microsoft.com/dotnet/api/system.boolean): Returns or sets whether the [TreeNode](https://docs.wisej.com/api/wisej.web/lists-and-grids/treeview/wisej.web.treenode) under the pointer gets selected on a right click. (Default: `False`) When the right click lands outside of a selected area the selection is not changed regardless of the value of [RightClickSelection](#rightclickselection). ### ![](https://1075938901-files.gitbook.io/~/files/v0/b/gitbook-x-prod.appspot.com/o/spaces%2F2HvlWXJQMV7DxhGzw7Y1%2Fuploads%2Fgit-blob-2389c55cd19719a73a5ae98e1528c8dc8525cc35%2Finstance.png?alt=media) Scrollable [Boolean](https://docs.microsoft.com/dotnet/api/system.boolean): Returns or sets whether the tree view control displays scroll bars when they are needed. (Default: `True`) ### ![](https://1075938901-files.gitbook.io/~/files/v0/b/gitbook-x-prod.appspot.com/o/spaces%2F2HvlWXJQMV7DxhGzw7Y1%2Fuploads%2Fgit-blob-2389c55cd19719a73a5ae98e1528c8dc8525cc35%2Finstance.png?alt=media) SelectedImageIndex [Int32](https://docs.microsoft.com/dotnet/api/system.int32): Returns or sets the image list index value of the image that is displayed when a [TreeNode](https://docs.wisej.com/api/wisej.web/lists-and-grids/treeview/wisej.web.treenode) is selected. (Default: `-1`) **Throws:** * [ArgumentException](https://docs.microsoft.com/dotnet/api/system.argumentexception)\ The index assigned value is less than -1. ### ![](https://1075938901-files.gitbook.io/~/files/v0/b/gitbook-x-prod.appspot.com/o/spaces%2F2HvlWXJQMV7DxhGzw7Y1%2Fuploads%2Fgit-blob-2389c55cd19719a73a5ae98e1528c8dc8525cc35%2Finstance.png?alt=media) SelectedImageKey [String](https://docs.microsoft.com/dotnet/api/system.string): Returns or sets the key of the default image shown when a [TreeNode](https://docs.wisej.com/api/wisej.web/lists-and-grids/treeview/wisej.web.treenode) is selected. (Default: `""`) ### ![](https://1075938901-files.gitbook.io/~/files/v0/b/gitbook-x-prod.appspot.com/o/spaces%2F2HvlWXJQMV7DxhGzw7Y1%2Fuploads%2Fgit-blob-2389c55cd19719a73a5ae98e1528c8dc8525cc35%2Finstance.png?alt=media) SelectedNode [TreeNode](https://docs.wisej.com/api/wisej.web/lists-and-grids/treeview/wisej.web.treenode): Returns or sets the tree node that is currently selected in the tree view control. ### ![](https://1075938901-files.gitbook.io/~/files/v0/b/gitbook-x-prod.appspot.com/o/spaces%2F2HvlWXJQMV7DxhGzw7Y1%2Fuploads%2Fgit-blob-2389c55cd19719a73a5ae98e1528c8dc8525cc35%2Finstance.png?alt=media) SelectedNodes [TreeNode\[\]](https://docs.wisej.com/api/wisej.web/lists-and-grids/treeview/wisej.web.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. ### ![](https://1075938901-files.gitbook.io/~/files/v0/b/gitbook-x-prod.appspot.com/o/spaces%2F2HvlWXJQMV7DxhGzw7Y1%2Fuploads%2Fgit-blob-2389c55cd19719a73a5ae98e1528c8dc8525cc35%2Finstance.png?alt=media) SelectionMode [SelectionMode](https://docs.wisej.com/api/wisej.web/enumerations/wisej.web.selectionmode): Returns or sets the method in which items are selected in the [TreeView](https://docs.wisej.com/api/wisej.web/lists-and-grids/treeview). (Default: `One`) ### ![](https://1075938901-files.gitbook.io/~/files/v0/b/gitbook-x-prod.appspot.com/o/spaces%2F2HvlWXJQMV7DxhGzw7Y1%2Fuploads%2Fgit-blob-2389c55cd19719a73a5ae98e1528c8dc8525cc35%2Finstance.png?alt=media) ShowNodeToolTips [Boolean](https://docs.microsoft.com/dotnet/api/system.boolean): Returns or sets a value indicating ToolTips are shown when the mouse pointer hovers over a [TreeNode](https://docs.wisej.com/api/wisej.web/lists-and-grids/treeview/wisej.web.treenode). (Default: `False`) ### ![](https://1075938901-files.gitbook.io/~/files/v0/b/gitbook-x-prod.appspot.com/o/spaces%2F2HvlWXJQMV7DxhGzw7Y1%2Fuploads%2Fgit-blob-2389c55cd19719a73a5ae98e1528c8dc8525cc35%2Finstance.png?alt=media) ShowPlusMinus [Boolean](https://docs.microsoft.com/dotnet/api/system.boolean): Returns or sets whether plus-sign (+) and minus-sign (-) buttons are displayed next to tree nodes that contain child tree nodes. (Default: `True`) ### ![](https://1075938901-files.gitbook.io/~/files/v0/b/gitbook-x-prod.appspot.com/o/spaces%2F2HvlWXJQMV7DxhGzw7Y1%2Fuploads%2Fgit-blob-2389c55cd19719a73a5ae98e1528c8dc8525cc35%2Finstance.png?alt=media) ShowRootLines [Boolean](https://docs.microsoft.com/dotnet/api/system.boolean): Returns or sets whether the expand/collapse icon is displayed for the root nodes (the firs level nodes). (Default: `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. ### ![](https://1075938901-files.gitbook.io/~/files/v0/b/gitbook-x-prod.appspot.com/o/spaces%2F2HvlWXJQMV7DxhGzw7Y1%2Fuploads%2Fgit-blob-2389c55cd19719a73a5ae98e1528c8dc8525cc35%2Finstance.png?alt=media) Sorted [Boolean](https://docs.microsoft.com/dotnet/api/system.boolean): Returns or sets whether the tree nodes in the tree view are sorted. (Default: `False`) ### ![](https://1075938901-files.gitbook.io/~/files/v0/b/gitbook-x-prod.appspot.com/o/spaces%2F2HvlWXJQMV7DxhGzw7Y1%2Fuploads%2Fgit-blob-2389c55cd19719a73a5ae98e1528c8dc8525cc35%2Finstance.png?alt=media) StateImageList [ImageList](https://docs.wisej.com/api/wisej.web/content/imagelist): Returns or sets the image list that is used to indicate the state of the [TreeView](https://docs.wisej.com/api/wisej.web/lists-and-grids/treeview) and its nodes. (Default: `null`) ### ![](https://1075938901-files.gitbook.io/~/files/v0/b/gitbook-x-prod.appspot.com/o/spaces%2F2HvlWXJQMV7DxhGzw7Y1%2Fuploads%2Fgit-blob-2389c55cd19719a73a5ae98e1528c8dc8525cc35%2Finstance.png?alt=media) Tools [ComponentToolCollection](https://docs.wisej.com/api/wisej.web/editors/wisej.web.componenttoolcollection): Returns the instance of [ComponentToolCollection](https://docs.wisej.com/api/wisej.web/editors/wisej.web.componenttoolcollection) associated with this control. ### ![](https://1075938901-files.gitbook.io/~/files/v0/b/gitbook-x-prod.appspot.com/o/spaces%2F2HvlWXJQMV7DxhGzw7Y1%2Fuploads%2Fgit-blob-2389c55cd19719a73a5ae98e1528c8dc8525cc35%2Finstance.png?alt=media) TopNode [TreeNode](https://docs.wisej.com/api/wisej.web/lists-and-grids/treeview/wisej.web.treenode): Returns or sets the first fully-visible tree node in the tree view control. ### ![](https://1075938901-files.gitbook.io/~/files/v0/b/gitbook-x-prod.appspot.com/o/spaces%2F2HvlWXJQMV7DxhGzw7Y1%2Fuploads%2Fgit-blob-2389c55cd19719a73a5ae98e1528c8dc8525cc35%2Finstance.png?alt=media) TreeViewNodeSorter [IComparer\](https://docs.microsoft.com/dotnet/api/system.collections.generic.icomparer-1): Returns or sets the implementation of [IComparer](https://docs.microsoft.com/dotnet/api/system.collections.icomparer) to perform a custom sort of the [TreeView](https://docs.wisej.com/api/wisej.web/lists-and-grids/treeview) nodes. ### ![](https://1075938901-files.gitbook.io/~/files/v0/b/gitbook-x-prod.appspot.com/o/spaces%2F2HvlWXJQMV7DxhGzw7Y1%2Fuploads%2Fgit-blob-2389c55cd19719a73a5ae98e1528c8dc8525cc35%2Finstance.png?alt=media) VirtualScroll [Boolean](https://docs.microsoft.com/dotnet/api/system.boolean): Enables or disables virtual scrolling for the [TreeView](https://docs.wisej.com/api/wisej.web/lists-and-grids/treeview). When virtual scrolling is enabled, only the visible nodes are rendered in the browser allowing the [TreeView](https://docs.wisej.com/api/wisej.web/lists-and-grids/treeview) to host virtually unlimited nodes without any performance loss. (Default: `False`) When [VirtualScroll](#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](#virtualscroll) is off (default).\ Setting the property [PrefetchItems](#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 ### ![](https://1075938901-files.gitbook.io/~/files/v0/b/gitbook-x-prod.appspot.com/o/spaces%2F2HvlWXJQMV7DxhGzw7Y1%2Fuploads%2Fgit-blob-2389c55cd19719a73a5ae98e1528c8dc8525cc35%2Finstance.png?alt=media) BeginUpdate() This method has no effect on this control. ### ![](https://1075938901-files.gitbook.io/~/files/v0/b/gitbook-x-prod.appspot.com/o/spaces%2F2HvlWXJQMV7DxhGzw7Y1%2Fuploads%2Fgit-blob-2389c55cd19719a73a5ae98e1528c8dc8525cc35%2Finstance.png?alt=media) ClearSelected() Unselects all nodes in the [TreeView](https://docs.wisej.com/api/wisej.web/lists-and-grids/treeview). ### ![](https://1075938901-files.gitbook.io/~/files/v0/b/gitbook-x-prod.appspot.com/o/spaces%2F2HvlWXJQMV7DxhGzw7Y1%2Fuploads%2Fgit-blob-2389c55cd19719a73a5ae98e1528c8dc8525cc35%2Finstance.png?alt=media) CollapseAll() Collapses all the tree nodes. ### ![](https://1075938901-files.gitbook.io/~/files/v0/b/gitbook-x-prod.appspot.com/o/spaces%2F2HvlWXJQMV7DxhGzw7Y1%2Fuploads%2Fgit-blob-9bf7fa01e02f4da0f9ef90d3b049ae43e664919e%2Fprotected.png?alt=media) Dispose(disposing) Disposes the control. | Parameter | Type | Description | | ------------- | --------------------------------------------------------------- | --------------------------------------------------------------------------- | | **disposing** | [Boolean](https://docs.microsoft.com/dotnet/api/system.boolean) | true when this method is called by the application rather than a finalizer. | ### ![](https://1075938901-files.gitbook.io/~/files/v0/b/gitbook-x-prod.appspot.com/o/spaces%2F2HvlWXJQMV7DxhGzw7Y1%2Fuploads%2Fgit-blob-2389c55cd19719a73a5ae98e1528c8dc8525cc35%2Finstance.png?alt=media) EndUpdate() This method has no effect on this control. ### ![](https://1075938901-files.gitbook.io/~/files/v0/b/gitbook-x-prod.appspot.com/o/spaces%2F2HvlWXJQMV7DxhGzw7Y1%2Fuploads%2Fgit-blob-2389c55cd19719a73a5ae98e1528c8dc8525cc35%2Finstance.png?alt=media) ExpandAll() Expands all the tree nodes. ### ![](https://1075938901-files.gitbook.io/~/files/v0/b/gitbook-x-prod.appspot.com/o/spaces%2F2HvlWXJQMV7DxhGzw7Y1%2Fuploads%2Fgit-blob-2389c55cd19719a73a5ae98e1528c8dc8525cc35%2Finstance.png?alt=media) 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](https://docs.microsoft.com/dotnet/api/system.boolean) | true to count the [TreeNode](https://docs.wisej.com/api/wisej.web/lists-and-grids/treeview/wisej.web.treenode) items that the subtrees contain; otherwise, false. | **Returns:** [Int32](https://docs.microsoft.com/dotnet/api/system.int32). The number of tree nodes, optionally including those in all subtrees, assigned to the tree view control. ### ![](https://1075938901-files.gitbook.io/~/files/v0/b/gitbook-x-prod.appspot.com/o/spaces%2F2HvlWXJQMV7DxhGzw7Y1%2Fuploads%2Fgit-blob-2389c55cd19719a73a5ae98e1528c8dc8525cc35%2Finstance.png?alt=media) GetSelected(node) Returns a value indicating whether the specified [TreeNode](https://docs.wisej.com/api/wisej.web/lists-and-grids/treeview/wisej.web.treenode) is selected. | Parameter | Type | Description | | --------- | -------------------------------------------------------------------------------------------- | ---------------------------------------------------------------------------------------------------------- | | **node** | [TreeNode](https://docs.wisej.com/api/wisej.web/lists-and-grids/treeview/wisej.web.treenode) | The [TreeNode](https://docs.wisej.com/api/wisej.web/lists-and-grids/treeview/wisej.web.treenode) to check. | **Returns:** [Boolean](https://docs.microsoft.com/dotnet/api/system.boolean). true if the specified [TreeNode](https://docs.wisej.com/api/wisej.web/lists-and-grids/treeview/wisej.web.treenode) is currently selected in the [TreeView](https://docs.wisej.com/api/wisej.web/lists-and-grids/treeview); otherwise, false. **Throws:** * [ArgumentNullException](https://docs.microsoft.com/dotnet/api/system.argumentnullexception)\ The specified *node* is null. * [ArgumentException](https://docs.microsoft.com/dotnet/api/system.argumentexception)\ The specified *node* is currently assigned to another [TreeView](https://docs.wisej.com/api/wisej.web/lists-and-grids/treeview). ### ![](https://1075938901-files.gitbook.io/~/files/v0/b/gitbook-x-prod.appspot.com/o/spaces%2F2HvlWXJQMV7DxhGzw7Y1%2Fuploads%2Fgit-blob-9bf7fa01e02f4da0f9ef90d3b049ae43e664919e%2Fprotected.png?alt=media) OnAddReferences(items) Returns a collection of referenced components or collection of components. | Parameter | Type | Description | | --------- | ----------------------------------------------------------------------- | ----------- | | **items** | [IList](https://docs.microsoft.com/dotnet/api/system.collections.ilist) | | ### ![](https://1075938901-files.gitbook.io/~/files/v0/b/gitbook-x-prod.appspot.com/o/spaces%2F2HvlWXJQMV7DxhGzw7Y1%2Fuploads%2Fgit-blob-9bf7fa01e02f4da0f9ef90d3b049ae43e664919e%2Fprotected.png?alt=media) OnAfterCheck(e) Fires the [AfterCheck](#aftercheck) event. | Parameter | Type | Description | | --------- | -------------------------------------------------------------------------------------------------------------- | ---------------------------------------------------------------------------------------------------------------------------------------------- | | **e** | [TreeViewEventArgs](https://docs.wisej.com/api/wisej.web/lists-and-grids/treeview/wisej.web.treevieweventargs) | A [TreeViewEventArgs](https://docs.wisej.com/api/wisej.web/lists-and-grids/treeview/wisej.web.treevieweventargs) that contains the event data. | ### ![](https://1075938901-files.gitbook.io/~/files/v0/b/gitbook-x-prod.appspot.com/o/spaces%2F2HvlWXJQMV7DxhGzw7Y1%2Fuploads%2Fgit-blob-9bf7fa01e02f4da0f9ef90d3b049ae43e664919e%2Fprotected.png?alt=media) OnAfterCollapse(e) Fires the [AfterCollapse](#aftercollapse) event. | Parameter | Type | Description | | --------- | -------------------------------------------------------------------------------------------------------------- | ---------------------------------------------------------------------------------------------------------------------------------------------- | | **e** | [TreeViewEventArgs](https://docs.wisej.com/api/wisej.web/lists-and-grids/treeview/wisej.web.treevieweventargs) | A [TreeViewEventArgs](https://docs.wisej.com/api/wisej.web/lists-and-grids/treeview/wisej.web.treevieweventargs) that contains the event data. | ### ![](https://1075938901-files.gitbook.io/~/files/v0/b/gitbook-x-prod.appspot.com/o/spaces%2F2HvlWXJQMV7DxhGzw7Y1%2Fuploads%2Fgit-blob-9bf7fa01e02f4da0f9ef90d3b049ae43e664919e%2Fprotected.png?alt=media) OnAfterExpand(e) Fires the [AfterExpand](#afterexpand) event. | Parameter | Type | Description | | --------- | -------------------------------------------------------------------------------------------------------------- | ---------------------------------------------------------------------------------------------------------------------------------------------- | | **e** | [TreeViewEventArgs](https://docs.wisej.com/api/wisej.web/lists-and-grids/treeview/wisej.web.treevieweventargs) | A [TreeViewEventArgs](https://docs.wisej.com/api/wisej.web/lists-and-grids/treeview/wisej.web.treevieweventargs) that contains the event data. | ### ![](https://1075938901-files.gitbook.io/~/files/v0/b/gitbook-x-prod.appspot.com/o/spaces%2F2HvlWXJQMV7DxhGzw7Y1%2Fuploads%2Fgit-blob-9bf7fa01e02f4da0f9ef90d3b049ae43e664919e%2Fprotected.png?alt=media) OnAfterLabelEdit(e) Fires the [AfterLabelEdit](#afterlabeledit) event. | Parameter | Type | Description | | --------- | ------------------------------------------------------------------------------------------------------------------------ | -------------------------------------------------------------------------------------------------------------------------------------------------------- | | **e** | [NodeLabelEditEventArgs](https://docs.wisej.com/api/wisej.web/lists-and-grids/treeview/wisej.web.nodelabelediteventargs) | A [NodeLabelEditEventArgs](https://docs.wisej.com/api/wisej.web/lists-and-grids/treeview/wisej.web.nodelabelediteventargs) that contains the event data. | ### ![](https://1075938901-files.gitbook.io/~/files/v0/b/gitbook-x-prod.appspot.com/o/spaces%2F2HvlWXJQMV7DxhGzw7Y1%2Fuploads%2Fgit-blob-9bf7fa01e02f4da0f9ef90d3b049ae43e664919e%2Fprotected.png?alt=media) OnAfterSelect(e) Fires the [AfterSelect](#afterselect) event. | Parameter | Type | Description | | --------- | -------------------------------------------------------------------------------------------------------------- | ---------------------------------------------------------------------------------------------------------------------------------------------- | | **e** | [TreeViewEventArgs](https://docs.wisej.com/api/wisej.web/lists-and-grids/treeview/wisej.web.treevieweventargs) | A [TreeViewEventArgs](https://docs.wisej.com/api/wisej.web/lists-and-grids/treeview/wisej.web.treevieweventargs) that contains the event data. | ### ![](https://1075938901-files.gitbook.io/~/files/v0/b/gitbook-x-prod.appspot.com/o/spaces%2F2HvlWXJQMV7DxhGzw7Y1%2Fuploads%2Fgit-blob-9bf7fa01e02f4da0f9ef90d3b049ae43e664919e%2Fprotected.png?alt=media) OnBeforeCheck(e) Fires the [BeforeCheck](#beforecheck) event. | Parameter | Type | Description | | --------- | -------------------------------------------------------------------------------------------------------------------------- | ---------------------------------------------------------------------------------------------------------------------------------------------------------- | | **e** | [TreeViewCancelEventArgs](https://docs.wisej.com/api/wisej.web/lists-and-grids/treeview/wisej.web.treeviewcanceleventargs) | A [TreeViewCancelEventArgs](https://docs.wisej.com/api/wisej.web/lists-and-grids/treeview/wisej.web.treeviewcanceleventargs) that contains the event data. | ### ![](https://1075938901-files.gitbook.io/~/files/v0/b/gitbook-x-prod.appspot.com/o/spaces%2F2HvlWXJQMV7DxhGzw7Y1%2Fuploads%2Fgit-blob-9bf7fa01e02f4da0f9ef90d3b049ae43e664919e%2Fprotected.png?alt=media) OnBeforeCollapse(e) Fires the [BeforeCollapse](#beforecollapse) event. | Parameter | Type | Description | | --------- | -------------------------------------------------------------------------------------------------------------------------- | ---------------------------------------------------------------------------------------------------------------------------------------------------------- | | **e** | [TreeViewCancelEventArgs](https://docs.wisej.com/api/wisej.web/lists-and-grids/treeview/wisej.web.treeviewcanceleventargs) | A [TreeViewCancelEventArgs](https://docs.wisej.com/api/wisej.web/lists-and-grids/treeview/wisej.web.treeviewcanceleventargs) that contains the event data. | ### ![](https://1075938901-files.gitbook.io/~/files/v0/b/gitbook-x-prod.appspot.com/o/spaces%2F2HvlWXJQMV7DxhGzw7Y1%2Fuploads%2Fgit-blob-9bf7fa01e02f4da0f9ef90d3b049ae43e664919e%2Fprotected.png?alt=media) OnBeforeExpand(e) Fires the [BeforeExpand](#beforeexpand) event. | Parameter | Type | Description | | --------- | -------------------------------------------------------------------------------------------------------------------------- | ---------------------------------------------------------------------------------------------------------------------------------------------------------- | | **e** | [TreeViewCancelEventArgs](https://docs.wisej.com/api/wisej.web/lists-and-grids/treeview/wisej.web.treeviewcanceleventargs) | A [TreeViewCancelEventArgs](https://docs.wisej.com/api/wisej.web/lists-and-grids/treeview/wisej.web.treeviewcanceleventargs) that contains the event data. | ### ![](https://1075938901-files.gitbook.io/~/files/v0/b/gitbook-x-prod.appspot.com/o/spaces%2F2HvlWXJQMV7DxhGzw7Y1%2Fuploads%2Fgit-blob-9bf7fa01e02f4da0f9ef90d3b049ae43e664919e%2Fprotected.png?alt=media) OnBeforeLabelEdit(e) Fires the [BeforeLabelEdit](#beforelabeledit) event. | Parameter | Type | Description | | --------- | ------------------------------------------------------------------------------------------------------------------------ | -------------------------------------------------------------------------------------------------------------------------------------------------------- | | **e** | [NodeLabelEditEventArgs](https://docs.wisej.com/api/wisej.web/lists-and-grids/treeview/wisej.web.nodelabelediteventargs) | A [NodeLabelEditEventArgs](https://docs.wisej.com/api/wisej.web/lists-and-grids/treeview/wisej.web.nodelabelediteventargs) that contains the event data. | ### ![](https://1075938901-files.gitbook.io/~/files/v0/b/gitbook-x-prod.appspot.com/o/spaces%2F2HvlWXJQMV7DxhGzw7Y1%2Fuploads%2Fgit-blob-9bf7fa01e02f4da0f9ef90d3b049ae43e664919e%2Fprotected.png?alt=media) OnBeforeSelect(e) Fires the [BeforeSelect](#beforeselect) event. | Parameter | Type | Description | | --------- | -------------------------------------------------------------------------------------------------------------------------- | ---------------------------------------------------------------------------------------------------------------------------------------------------------- | | **e** | [TreeViewCancelEventArgs](https://docs.wisej.com/api/wisej.web/lists-and-grids/treeview/wisej.web.treeviewcanceleventargs) | A [TreeViewCancelEventArgs](https://docs.wisej.com/api/wisej.web/lists-and-grids/treeview/wisej.web.treeviewcanceleventargs) that contains the event data. | ### ![](https://1075938901-files.gitbook.io/~/files/v0/b/gitbook-x-prod.appspot.com/o/spaces%2F2HvlWXJQMV7DxhGzw7Y1%2Fuploads%2Fgit-blob-9bf7fa01e02f4da0f9ef90d3b049ae43e664919e%2Fprotected.png?alt=media) OnCreateControl() Creates and register this control and all its children. ### ![](https://1075938901-files.gitbook.io/~/files/v0/b/gitbook-x-prod.appspot.com/o/spaces%2F2HvlWXJQMV7DxhGzw7Y1%2Fuploads%2Fgit-blob-9bf7fa01e02f4da0f9ef90d3b049ae43e664919e%2Fprotected.png?alt=media) OnItemDrag(e) ![](https://1075938901-files.gitbook.io/~/files/v0/b/gitbook-x-prod.appspot.com/o/spaces%2F2HvlWXJQMV7DxhGzw7Y1%2Fuploads%2Fgit-blob-72ee9aade2e798319ef8cd025a59345103436978%2Fdeprecated.png?alt=media)**Deprecated**: This method is deprecated. Use OnNodeDrag instead.\ Fires the [ItemDrag](#itemdrag) event. | Parameter | Type | Description | | --------- | -------------------------------------------------------------------------------------------------------------- | ----------------------------------------------------------------------------------------------------------------------------------------------- | | **e** | [ItemDragEventArgs](https://docs.wisej.com/api/wisej.web/lists-and-grids/treeview/wisej.web.itemdrageventargs) | An [ItemDragEventArgs](https://docs.wisej.com/api/wisej.web/lists-and-grids/treeview/wisej.web.itemdrageventargs) that contains the event data. | ### ![](https://1075938901-files.gitbook.io/~/files/v0/b/gitbook-x-prod.appspot.com/o/spaces%2F2HvlWXJQMV7DxhGzw7Y1%2Fuploads%2Fgit-blob-9bf7fa01e02f4da0f9ef90d3b049ae43e664919e%2Fprotected.png?alt=media) OnNodeDrag(e) Fires the [NodeDrag](#nodedrag) event. | Parameter | Type | Description | | --------- | ------------------------------------------------------------------------------------------------------------------------------ | --------------------------------------------------------------------------------------------------------------------------------------------------------------- | | **e** | [TreeViewNodeDragEventArgs](https://docs.wisej.com/api/wisej.web/lists-and-grids/treeview/wisej.web.treeviewnodedrageventargs) | An [TreeViewNodeDragEventArgs](https://docs.wisej.com/api/wisej.web/lists-and-grids/treeview/wisej.web.treeviewnodedrageventargs) that contains the event data. | ### ![](https://1075938901-files.gitbook.io/~/files/v0/b/gitbook-x-prod.appspot.com/o/spaces%2F2HvlWXJQMV7DxhGzw7Y1%2Fuploads%2Fgit-blob-9bf7fa01e02f4da0f9ef90d3b049ae43e664919e%2Fprotected.png?alt=media) OnNodeMouseClick(e) Fires the [NodeMouseClick](#nodemouseclick) event. | Parameter | Type | Description | | --------- | ---------------------------------------------------------------------------------------------------------------------------------- | ------------------------------------------------------------------------------------------------------------------------------------------------------------------ | | **e** | [TreeNodeMouseClickEventArgs](https://docs.wisej.com/api/wisej.web/lists-and-grids/treeview/wisej.web.treenodemouseclickeventargs) | A [TreeNodeMouseClickEventArgs](https://docs.wisej.com/api/wisej.web/lists-and-grids/treeview/wisej.web.treenodemouseclickeventargs) that contains the event data. | ### ![](https://1075938901-files.gitbook.io/~/files/v0/b/gitbook-x-prod.appspot.com/o/spaces%2F2HvlWXJQMV7DxhGzw7Y1%2Fuploads%2Fgit-blob-9bf7fa01e02f4da0f9ef90d3b049ae43e664919e%2Fprotected.png?alt=media) OnNodeMouseDoubleClick(e) Fires the [NodeMouseDoubleClick](#nodemousedoubleclick) event. | Parameter | Type | Description | | --------- | ---------------------------------------------------------------------------------------------------------------------------------- | ------------------------------------------------------------------------------------------------------------------------------------------------------------------ | | **e** | [TreeNodeMouseClickEventArgs](https://docs.wisej.com/api/wisej.web/lists-and-grids/treeview/wisej.web.treenodemouseclickeventargs) | A [TreeNodeMouseClickEventArgs](https://docs.wisej.com/api/wisej.web/lists-and-grids/treeview/wisej.web.treenodemouseclickeventargs) that contains the event data. | ### ![](https://1075938901-files.gitbook.io/~/files/v0/b/gitbook-x-prod.appspot.com/o/spaces%2F2HvlWXJQMV7DxhGzw7Y1%2Fuploads%2Fgit-blob-9bf7fa01e02f4da0f9ef90d3b049ae43e664919e%2Fprotected.png?alt=media) OnNodeMouseHover(e) Fires the [NodeMouseHover](#nodemousehover) event. | Parameter | Type | Description | | --------- | ---------------------------------------------------------------------------------------------------------------------------------- | -------------------------------------------------------------------------------------------------------------------------------------------------------------------- | | **e** | [TreeNodeMouseHoverEventArgs](https://docs.wisej.com/api/wisej.web/lists-and-grids/treeview/wisej.web.treenodemousehovereventargs) | The [TreeNodeMouseHoverEventArgs](https://docs.wisej.com/api/wisej.web/lists-and-grids/treeview/wisej.web.treenodemousehovereventargs) that contains the event data. | ### ![](https://1075938901-files.gitbook.io/~/files/v0/b/gitbook-x-prod.appspot.com/o/spaces%2F2HvlWXJQMV7DxhGzw7Y1%2Fuploads%2Fgit-blob-9bf7fa01e02f4da0f9ef90d3b049ae43e664919e%2Fprotected.png?alt=media) OnNodeMouseLeave(e) Fires the [NodeMouseLeave](#nodemouseleave) event. | Parameter | Type | Description | | --------- | ---------------------------------------------------------------------------------------------------------------------------------- | -------------------------------------------------------------------------------------------------------------------------------------------------------------------- | | **e** | [TreeNodeMouseHoverEventArgs](https://docs.wisej.com/api/wisej.web/lists-and-grids/treeview/wisej.web.treenodemousehovereventargs) | The [TreeNodeMouseHoverEventArgs](https://docs.wisej.com/api/wisej.web/lists-and-grids/treeview/wisej.web.treenodemousehovereventargs) that contains the event data. | ### ![](https://1075938901-files.gitbook.io/~/files/v0/b/gitbook-x-prod.appspot.com/o/spaces%2F2HvlWXJQMV7DxhGzw7Y1%2Fuploads%2Fgit-blob-9bf7fa01e02f4da0f9ef90d3b049ae43e664919e%2Fprotected.png?alt=media) OnToolClick(e) Fires the ToolClick event. | Parameter | Type | Description | | --------- | ----------------------------------------------------------------------------------------------- | ------------------------------------------------------------------------------------------------------------------------------- | | **e** | [ToolClickEventArgs](https://docs.wisej.com/api/wisej.web/editors/wisej.web.toolclickeventargs) | A [ToolClickEventArgs](https://docs.wisej.com/api/wisej.web/editors/wisej.web.toolclickeventargs) that contains the event data. | ### ![](https://1075938901-files.gitbook.io/~/files/v0/b/gitbook-x-prod.appspot.com/o/spaces%2F2HvlWXJQMV7DxhGzw7Y1%2Fuploads%2Fgit-blob-9bf7fa01e02f4da0f9ef90d3b049ae43e664919e%2Fprotected.png?alt=media) OnWebEvent(e) Processes the event from the client. | Parameter | Type | Description | | --------- | ------------------------------------------------------------------------------ | ---------------- | | **e** | [WisejEventArgs](https://docs.wisej.com/api/wisej.core/general/wisejeventargs) | Event arguments. | ### ![](https://1075938901-files.gitbook.io/~/files/v0/b/gitbook-x-prod.appspot.com/o/spaces%2F2HvlWXJQMV7DxhGzw7Y1%2Fuploads%2Fgit-blob-9bf7fa01e02f4da0f9ef90d3b049ae43e664919e%2Fprotected.png?alt=media) OnWebRender(config) Renders the client component. | Parameter | Type | Description | | ---------- | ------------------------------------------------------------- | ----------------------------- | | **config** | [Object](https://docs.microsoft.com/dotnet/api/system.object) | Dynamic configuration object. | ### ![](https://1075938901-files.gitbook.io/~/files/v0/b/gitbook-x-prod.appspot.com/o/spaces%2F2HvlWXJQMV7DxhGzw7Y1%2Fuploads%2Fgit-blob-9bf7fa01e02f4da0f9ef90d3b049ae43e664919e%2Fprotected.png?alt=media) OnWebUpdate(state) Updates the client component using the state information. | Parameter | Type | Description | | --------- | ------------------------------------------------------------- | --------------------- | | **state** | [Object](https://docs.microsoft.com/dotnet/api/system.object) | Dynamic state object. | ### ![](https://1075938901-files.gitbook.io/~/files/v0/b/gitbook-x-prod.appspot.com/o/spaces%2F2HvlWXJQMV7DxhGzw7Y1%2Fuploads%2Fgit-blob-2389c55cd19719a73a5ae98e1528c8dc8525cc35%2Finstance.png?alt=media) SetSelected(node, selected) Selects or clears the selection for the specified [TreeNode](https://docs.wisej.com/api/wisej.web/lists-and-grids/treeview/wisej.web.treenode) in a [TreeView](https://docs.wisej.com/api/wisej.web/lists-and-grids/treeview). | Parameter | Type | Description | | ------------ | -------------------------------------------------------------------------------------------- | ---------------------------------------------------------------------------------------------------------------------------------------------------------- | | **node** | [TreeNode](https://docs.wisej.com/api/wisej.web/lists-and-grids/treeview/wisej.web.treenode) | The [TreeNode](https://docs.wisej.com/api/wisej.web/lists-and-grids/treeview/wisej.web.treenode) to select. | | **selected** | [Boolean](https://docs.microsoft.com/dotnet/api/system.boolean) | True to select the specified [TreeNode](https://docs.wisej.com/api/wisej.web/lists-and-grids/treeview/wisej.web.treenode), otherwise false to deselect it. | **Throws:** * [ArgumentNullException](https://docs.microsoft.com/dotnet/api/system.argumentnullexception)\ The specified *node* is null. * [ArgumentException](https://docs.microsoft.com/dotnet/api/system.argumentexception)\ The specified *node* is currently assigned to another [TreeView](https://docs.wisej.com/api/wisej.web/lists-and-grids/treeview). * [InvalidOperationException](https://docs.microsoft.com/dotnet/api/system.invalidoperationexception)\ The [SelectionMode](#selectionmode) property is set to None. ### ![](https://1075938901-files.gitbook.io/~/files/v0/b/gitbook-x-prod.appspot.com/o/spaces%2F2HvlWXJQMV7DxhGzw7Y1%2Fuploads%2Fgit-blob-2389c55cd19719a73a5ae98e1528c8dc8525cc35%2Finstance.png?alt=media) Sort() Sorts the items in [TreeView](https://docs.wisej.com/api/wisej.web/lists-and-grids/treeview) control. ## Events ### ![](https://1075938901-files.gitbook.io/~/files/v0/b/gitbook-x-prod.appspot.com/o/spaces%2F2HvlWXJQMV7DxhGzw7Y1%2Fuploads%2Fgit-blob-2389c55cd19719a73a5ae98e1528c8dc8525cc35%2Finstance.png?alt=media) AfterCheck [TreeViewEventHandler](https://docs.wisej.com/api/wisej.web/lists-and-grids/treeview/wisej.web.treevieweventhandler) Occurs after the tree node check box is checked. ### ![](https://1075938901-files.gitbook.io/~/files/v0/b/gitbook-x-prod.appspot.com/o/spaces%2F2HvlWXJQMV7DxhGzw7Y1%2Fuploads%2Fgit-blob-2389c55cd19719a73a5ae98e1528c8dc8525cc35%2Finstance.png?alt=media) AfterCollapse [TreeViewEventHandler](https://docs.wisej.com/api/wisej.web/lists-and-grids/treeview/wisej.web.treevieweventhandler) Occurs after the tree node is collapsed. ### ![](https://1075938901-files.gitbook.io/~/files/v0/b/gitbook-x-prod.appspot.com/o/spaces%2F2HvlWXJQMV7DxhGzw7Y1%2Fuploads%2Fgit-blob-2389c55cd19719a73a5ae98e1528c8dc8525cc35%2Finstance.png?alt=media) AfterExpand [TreeViewEventHandler](https://docs.wisej.com/api/wisej.web/lists-and-grids/treeview/wisej.web.treevieweventhandler) Occurs after the tree node is expanded. ### ![](https://1075938901-files.gitbook.io/~/files/v0/b/gitbook-x-prod.appspot.com/o/spaces%2F2HvlWXJQMV7DxhGzw7Y1%2Fuploads%2Fgit-blob-2389c55cd19719a73a5ae98e1528c8dc8525cc35%2Finstance.png?alt=media) AfterLabelEdit [NodeLabelEditEventHandler](https://docs.wisej.com/api/wisej.web/lists-and-grids/treeview/wisej.web.nodelabelediteventhandler) Occurs after the tree node label text is edited. ### ![](https://1075938901-files.gitbook.io/~/files/v0/b/gitbook-x-prod.appspot.com/o/spaces%2F2HvlWXJQMV7DxhGzw7Y1%2Fuploads%2Fgit-blob-2389c55cd19719a73a5ae98e1528c8dc8525cc35%2Finstance.png?alt=media) AfterSelect [TreeViewEventHandler](https://docs.wisej.com/api/wisej.web/lists-and-grids/treeview/wisej.web.treevieweventhandler) Occurs after the tree node is selected. ### ![](https://1075938901-files.gitbook.io/~/files/v0/b/gitbook-x-prod.appspot.com/o/spaces%2F2HvlWXJQMV7DxhGzw7Y1%2Fuploads%2Fgit-blob-2389c55cd19719a73a5ae98e1528c8dc8525cc35%2Finstance.png?alt=media) BeforeCheck [TreeViewCancelEventHandler](https://docs.wisej.com/api/wisej.web/lists-and-grids/treeview/wisej.web.treeviewcanceleventhandler) Occurs before the tree node check box is checked. ### ![](https://1075938901-files.gitbook.io/~/files/v0/b/gitbook-x-prod.appspot.com/o/spaces%2F2HvlWXJQMV7DxhGzw7Y1%2Fuploads%2Fgit-blob-2389c55cd19719a73a5ae98e1528c8dc8525cc35%2Finstance.png?alt=media) BeforeCollapse [TreeViewCancelEventHandler](https://docs.wisej.com/api/wisej.web/lists-and-grids/treeview/wisej.web.treeviewcanceleventhandler) Occurs before the tree node is collapsed. ### ![](https://1075938901-files.gitbook.io/~/files/v0/b/gitbook-x-prod.appspot.com/o/spaces%2F2HvlWXJQMV7DxhGzw7Y1%2Fuploads%2Fgit-blob-2389c55cd19719a73a5ae98e1528c8dc8525cc35%2Finstance.png?alt=media) BeforeExpand [TreeViewCancelEventHandler](https://docs.wisej.com/api/wisej.web/lists-and-grids/treeview/wisej.web.treeviewcanceleventhandler) Occurs before the tree node is expanded. ### ![](https://1075938901-files.gitbook.io/~/files/v0/b/gitbook-x-prod.appspot.com/o/spaces%2F2HvlWXJQMV7DxhGzw7Y1%2Fuploads%2Fgit-blob-2389c55cd19719a73a5ae98e1528c8dc8525cc35%2Finstance.png?alt=media) BeforeLabelEdit [NodeLabelEditEventHandler](https://docs.wisej.com/api/wisej.web/lists-and-grids/treeview/wisej.web.nodelabelediteventhandler) Occurs before the tree node label text is edited. ### ![](https://1075938901-files.gitbook.io/~/files/v0/b/gitbook-x-prod.appspot.com/o/spaces%2F2HvlWXJQMV7DxhGzw7Y1%2Fuploads%2Fgit-blob-2389c55cd19719a73a5ae98e1528c8dc8525cc35%2Finstance.png?alt=media) BeforeSelect [TreeViewCancelEventHandler](https://docs.wisej.com/api/wisej.web/lists-and-grids/treeview/wisej.web.treeviewcanceleventhandler) Occurs before the tree node is selected. ### ![](https://1075938901-files.gitbook.io/~/files/v0/b/gitbook-x-prod.appspot.com/o/spaces%2F2HvlWXJQMV7DxhGzw7Y1%2Fuploads%2Fgit-blob-2389c55cd19719a73a5ae98e1528c8dc8525cc35%2Finstance.png?alt=media) ItemDrag ![](https://1075938901-files.gitbook.io/~/files/v0/b/gitbook-x-prod.appspot.com/o/spaces%2F2HvlWXJQMV7DxhGzw7Y1%2Fuploads%2Fgit-blob-72ee9aade2e798319ef8cd025a59345103436978%2Fdeprecated.png?alt=media)**Deprecated**: This event is deprecated. Use NodeDrag instead.[ItemDragEventHandler](https://docs.wisej.com/api/wisej.web/lists-and-grids/treeview/wisej.web.itemdrageventhandler) Fired when the user begins dragging a node. ### ![](https://1075938901-files.gitbook.io/~/files/v0/b/gitbook-x-prod.appspot.com/o/spaces%2F2HvlWXJQMV7DxhGzw7Y1%2Fuploads%2Fgit-blob-2389c55cd19719a73a5ae98e1528c8dc8525cc35%2Finstance.png?alt=media) NodeDrag [TreeViewNodeDragEventHandler](https://docs.wisej.com/api/wisej.web/lists-and-grids/treeview/wisej.web.treeviewnodedrageventhandler) Fired when the user begins dragging a node. ### ![](https://1075938901-files.gitbook.io/~/files/v0/b/gitbook-x-prod.appspot.com/o/spaces%2F2HvlWXJQMV7DxhGzw7Y1%2Fuploads%2Fgit-blob-2389c55cd19719a73a5ae98e1528c8dc8525cc35%2Finstance.png?alt=media) NodeMouseClick [TreeNodeMouseClickEventHandler](https://docs.wisej.com/api/wisej.web/lists-and-grids/treeview/wisej.web.treenodemouseclickeventhandler) Fired when the user clicks a [TreeNode](https://docs.wisej.com/api/wisej.web/lists-and-grids/treeview/wisej.web.treenode) with the mouse. ### ![](https://1075938901-files.gitbook.io/~/files/v0/b/gitbook-x-prod.appspot.com/o/spaces%2F2HvlWXJQMV7DxhGzw7Y1%2Fuploads%2Fgit-blob-2389c55cd19719a73a5ae98e1528c8dc8525cc35%2Finstance.png?alt=media) NodeMouseDoubleClick [TreeNodeMouseClickEventHandler](https://docs.wisej.com/api/wisej.web/lists-and-grids/treeview/wisej.web.treenodemouseclickeventhandler) Fired when the user double-clicks a [TreeNode](https://docs.wisej.com/api/wisej.web/lists-and-grids/treeview/wisej.web.treenode) with the mouse. ### ![](https://1075938901-files.gitbook.io/~/files/v0/b/gitbook-x-prod.appspot.com/o/spaces%2F2HvlWXJQMV7DxhGzw7Y1%2Fuploads%2Fgit-blob-2389c55cd19719a73a5ae98e1528c8dc8525cc35%2Finstance.png?alt=media) NodeMouseHover [TreeNodeMouseHoverEventHandler](https://docs.wisej.com/api/wisej.web/lists-and-grids/treeview/wisej.web.treenodemousehovereventhandler) Fired when the mouse hovers over a [TreeNode](https://docs.wisej.com/api/wisej.web/lists-and-grids/treeview/wisej.web.treenode). ### ![](https://1075938901-files.gitbook.io/~/files/v0/b/gitbook-x-prod.appspot.com/o/spaces%2F2HvlWXJQMV7DxhGzw7Y1%2Fuploads%2Fgit-blob-2389c55cd19719a73a5ae98e1528c8dc8525cc35%2Finstance.png?alt=media) NodeMouseLeave [TreeNodeMouseHoverEventHandler](https://docs.wisej.com/api/wisej.web/lists-and-grids/treeview/wisej.web.treenodemousehovereventhandler) Fired when the mouse leaves the [TreeNode](https://docs.wisej.com/api/wisej.web/lists-and-grids/treeview/wisej.web.treenode). ### ![](https://1075938901-files.gitbook.io/~/files/v0/b/gitbook-x-prod.appspot.com/o/spaces%2F2HvlWXJQMV7DxhGzw7Y1%2Fuploads%2Fgit-blob-2389c55cd19719a73a5ae98e1528c8dc8525cc35%2Finstance.png?alt=media) ToolClick [ToolClickEventHandler](https://docs.wisej.com/api/wisej.web/editors/wisej.web.toolclickeventhandler) Fired when a [ComponentTool](https://docs.wisej.com/api/wisej.web/editors/wisej.web.componenttool) is clicked. ## Implements | Name | Description | | ---------------------------------------------------------------------------------------------------- | ---------------------------------------------------------------------------------------------------------------------------------------- | | [IUserData](https://docs.wisej.com/api/wisej.web/interfaces/wisej.web.iuserdata) | Provides access to the `UserData` and `Tag` properties associated to the component implementing this interface. | | [IBindableComponent](https://docs.wisej.com/api/wisej.web/data-binding/wisej.web.ibindablecomponent) | Bindable components implement this interface. | | [IDropTarget](https://docs.wisej.com/api/wisej.web/interfaces/wisej.web.idroptarget) | Controls that support drag & drop operations implement this interface. | | [IWisejComponent](https://docs.wisej.com/api/wisej.core/interfaces/wisej.core.iwisejcomponent) | All wisej components implement this interface. | | [IWisejControl](https://docs.wisej.com/api/wisej.core/interfaces/wisej.core.iwisejcontrol) | All wisej controls derived from the [Control](https://docs.wisej.com/api/wisej.web/general/control) class must implement this interface. | | [IWisejSerializable](https://docs.wisej.com/api/wisej.core/interfaces/wisej.core.iwisejserializable) | Allows an object to serialize itself. |