Class SfTreeView<TValue>

The TreeView component is used to represent hierarchical data in a tree like structure with advanced functions to edit, drag and drop, select with CheckBox and more. TreeView can be populated from a data source such as an array of data's or from DataManager.

Inheritance
System.Object
Syncfusion.Blazor.SfBaseComponent
SfTreeView<TValue>
Namespace: Syncfusion.Blazor.Navigations
Assembly: Syncfusion.Blazor.dll
Syntax
public class SfTreeView<TValue> : SfBaseComponent
Type Parameters
Name Description
TValue

Constructors

SfTreeView()

Declaration
public SfTreeView()

Properties

AllowDragAndDrop

Indicates whether the TreeView allows drag and drop of nodes. To drag and drop a node in desktop, hold the mouse on the node, drag it to the target node and drop the node by releasing the mouse. For touch devices, drag and drop operation is performed by touch, touch move and touch end.

Declaration
public bool AllowDragAndDrop { get; set; }
Property Value
Type Description
System.Boolean

AllowEditing

Enables or disables editing of the text in the TreeView node. When AllowEditing property is set to true, the TreeView allows you to edit the node by double clicking the node or by navigating to the node and pressing F2 key.

Declaration
public bool AllowEditing { get; set; }
Property Value
Type Description
System.Boolean

AllowMultiSelection

Enables or disables multi-selection of nodes. To select multiple nodes: Select the nodes by holding down the CTRL key while clicking on the nodes. Select consecutive nodes by clicking the first node to select and hold down the SHIFT key and click the last node to select.

Declaration
public bool AllowMultiSelection { get; set; }
Property Value
Type Description
System.Boolean

Animation

Specifies the type of animation applied on expanding and collapsing the nodes along with duration.

Declaration
public TreeViewNodeAnimationSettings Animation { get; set; }
Property Value
Type Description
TreeViewNodeAnimationSettings

AutoCheck

Allow us to specify the parent and child nodes to get auto check while we check or uncheck a node.

Declaration
public bool AutoCheck { get; set; }
Property Value
Type Description
System.Boolean

CheckedNodes

The CheckedNodes property is used to set the nodes that need to be checked or get the ID of nodes that are currently checked in the TreeView component. The checkedNodes property depends upon the value of showCheckBox property.

Declaration
public string[] CheckedNodes { get; set; }
Property Value
Type Description
System.String[]

CheckedNodesChanged

Specifies the callback to trigger when the checked nodes changes.

Declaration
public EventCallback<string[]> CheckedNodesChanged { get; set; }
Property Value
Type Description
Microsoft.AspNetCore.Components.EventCallback<System.String[]>

CssClass

Specifies the CSS classes to be added with root element of the TreeView to help customize the appearance of the component.

Declaration
public string CssClass { get; set; }
Property Value
Type Description
System.String

Disabled

Specifies a value that indicates whether the TreeView component is disabled or not. When set to true, user interaction will not be occurred in TreeView.

Declaration
public bool Disabled { get; set; }
Property Value
Type Description
System.Boolean

DropArea

Defines the area in which the draggable element movement will be occurring. Outside that area will be restricted for the draggable element movement. By default, the draggable element movement occurs in the entire page.

Declaration
public string DropArea { get; set; }
Property Value
Type Description
System.String

EnableHtmlSanitizer

Defines whether to allow the cross-scripting site or not.

Declaration
public bool EnableHtmlSanitizer { get; set; }
Property Value
Type Description
System.Boolean

EnablePersistence

Enables or disables persisting TreeView state between page reloads. If enabled, following APIs will persist.

  1. SelectedNodes - Represents the nodes that are selected in the TreeView component.
  2. checkedNodes - Represents the nodes that are checked in the TreeView component.
  3. expandedNodes - Represents the nodes that are expanded in the TreeView component.
Declaration
public bool EnablePersistence { get; set; }
Property Value
Type Description
System.Boolean

EnableRtl

Enable or disable rendering component in right to left direction.

Declaration
public bool EnableRtl { get; set; }
Property Value
Type Description
System.Boolean

ExpandedNodes

Represents the expanded nodes in the TreeView component. We can set the nodes that need to be expanded or get the ID of the nodes that are currently expanded by using this property.

Declaration
public string[] ExpandedNodes { get; set; }
Property Value
Type Description
System.String[]

ExpandedNodesChanged

Specifies the callback to trigger when the expanded nodes changes.

Declaration
public EventCallback<string[]> ExpandedNodesChanged { get; set; }
Property Value
Type Description
Microsoft.AspNetCore.Components.EventCallback<System.String[]>

ExpandOn

Specifies the action on which the node expands or collapses. The available actions are, Click - The expand/collapse operation happens when you single-click the node in both desktop and mobile devices. DblClick - The expand/collapse operation happens when you double-click the node in both desktop and mobile devices. None - The expand/collapse operation will not happen when you single-click or double-click the node in both desktop and mobile devices.

Declaration
public ExpandAction ExpandOn { get; set; }
Property Value
Type Description
ExpandAction

Fields

Specifies the data source and mapping fields to render TreeView nodes.

Declaration
public TreeViewFieldsSettings<TValue> Fields { get; set; }
Property Value
Type Description
TreeViewFieldsSettings<TValue>

FullRowNavigable

If this property is set to true, then the entire TreeView node will be navigate-able instead of text element.

Declaration
public bool FullRowNavigable { get; set; }
Property Value
Type Description
System.Boolean

FullRowSelect

On enabling this property, the entire row of the TreeView node gets selected by clicking a node. When disabled only the corresponding node's text gets selected.

Declaration
public bool FullRowSelect { get; set; }
Property Value
Type Description
System.Boolean

HtmlAttributes

Specify the HtmlAttributes for TreeView.

Declaration
public Dictionary<string, object> HtmlAttributes { get; set; }
Property Value
Type Description
System.Collections.Generic.Dictionary<System.String, System.Object>

ID

Sets id attribute for the treeview element.

Declaration
public string ID { get; set; }
Property Value
Type Description
System.String

LoadOnDemand

By default, the load on demand (Lazy load) is set to true. By disabling this property, all the tree nodes are rendered at the beginning itself.

Declaration
public bool LoadOnDemand { get; set; }
Property Value
Type Description
System.Boolean

SelectedNodes

Represents the selected nodes in the TreeView component. We can set the nodes that need to be selected or get the ID of the nodes that are currently selected by using this property. On enabling AllowMultiSelection property we can select multiple nodes and on disabling it we can select only a single node.

Declaration
public string[] SelectedNodes { get; set; }
Property Value
Type Description
System.String[]

SelectedNodesChanged

Specifies the callback to trigger when the selected nodes changes.

Declaration
public EventCallback<string[]> SelectedNodesChanged { get; set; }
Property Value
Type Description
Microsoft.AspNetCore.Components.EventCallback<System.String[]>

ShowCheckBox

Indicates that the nodes will display CheckBoxes in the TreeView. The CheckBox will be displayed next to the expand/collapse icon of the node.

Declaration
public bool ShowCheckBox { get; set; }
Property Value
Type Description
System.Boolean

sortOrder

Declaration
public SortOrder sortOrder { get; set; }
Property Value
Type Description
SortOrder

SortOrder

Specifies a value that indicates whether the nodes are sorted in the ascending or descending order, or are not sorted at all. The available types of sort order are, None - The nodes are not sorted. Ascending - The nodes are sorted in the ascending order. Descending - The nodes are sorted in the ascending order.

Declaration
public SortOrder SortOrder { get; set; }
Property Value
Type Description
SortOrder

TreeViewTemplates

Specifies the custom item template of TreeView Node item.

Declaration
public TreeViewTemplates<TValue> TreeViewTemplates { get; set; }
Property Value
Type Description
TreeViewTemplates<TValue>

Methods

AddNodes(List<TValue>, String)

Adds the collection of TreeView nodes based on target and index position. If target node is not specified, then the nodes are added as children of the given parentID or in the root level of TreeView.

Declaration
public Task AddNodes(List<TValue> nodes, string target = null)
Parameters
Type Name Description
System.Collections.Generic.List<TValue> nodes

A list of nodes to be added to the TreeView.
System.String target

Based on target nodes are added as children of the given parentID or in the root level of TreeView
Returns
Type Description
System.Threading.Tasks.Task

BeginEdit(String)

Instead of clicking on the TreeView node for editing, we can enable it by using BeginEdit property. On passing the node ID or element through this property, the edit textBox will be created for the particular node thus allowing us to edit it.

Declaration
public Task BeginEdit(string node)
Parameters
Type Name Description
System.String node

Specifies ID of TreeView node.
Returns
Type Description
System.Threading.Tasks.Task

BuildRenderTree(RenderTreeBuilder)

Declaration
protected override void BuildRenderTree(RenderTreeBuilder __builder)
Parameters
Type Name Description
Microsoft.AspNetCore.Components.Rendering.RenderTreeBuilder __builder

CheckAll(String[])

Checks all the unchecked nodes. You can also check specific nodes by passing array of unchecked nodes as argument to this method.

Declaration
public Task CheckAll(string[] nodesId = null)
Parameters
Type Name Description
System.String[] nodesId
Returns
Type Description
System.Threading.Tasks.Task

CollapseAll(String[])

Collapses all the expanded TreeView nodes. You can collapse specific nodes by passing array of nodes as argument to this method.

Declaration
public Task CollapseAll(string[] nodesId = null)
Parameters
Type Name Description
System.String[] nodesId
Returns
Type Description
System.Threading.Tasks.Task

DisableNodes(String[])

Disables the collection of nodes by passing the ID of nodes or node elements in the array.

Declaration
public Task DisableNodes(string[] nodes)
Parameters
Type Name Description
System.String[] nodes

Specifies the array of TreeView nodes ID.
Returns
Type Description
System.Threading.Tasks.Task

DropNodeAsChild(String, String, String)

Declaration
public Task DropNodeAsChild(string dragLi, string dropLi, string dragParentLi = null)
Parameters
Type Name Description
System.String dragLi
System.String dropLi
System.String dragParentLi
Returns
Type Description
System.Threading.Tasks.Task

DropNodeAsSibling(String, String, String, Nullable<Boolean>, String)

Declaration
public Task DropNodeAsSibling(string dragLi, string dropLi, string dropParentLi, Nullable<bool> pre, string dragParentLi)
Parameters
Type Name Description
System.String dragLi
System.String dropLi
System.String dropParentLi
System.Nullable<System.Boolean> pre
System.String dragParentLi
Returns
Type Description
System.Threading.Tasks.Task

EnableNodes(String[])

Enables the collection of disabled nodes by passing the ID of nodes or node elements in the array.

Declaration
public Task EnableNodes(string[] nodes)
Parameters
Type Name Description
System.String[] nodes

Specifies the array of TreeView nodes ID.
Returns
Type Description
System.Threading.Tasks.Task

EnsureVisible(String)

Ensures visibility of the TreeView node by using node ID or node element. When many TreeView nodes are present and we need to find a particular node, EnsureVisible property helps bring the node to visibility by expanding the TreeView and scrolling to the specific node.

Declaration
public Task EnsureVisible(string node)
Parameters
Type Name Description
System.String node

Specifies ID of TreeView node.
Returns
Type Description
System.Threading.Tasks.Task

ExpandAll(String[])

Expands all the collapsed TreeView nodes. You can expand the specific nodes by passing the array of collapsed nodes

Declaration
public Task ExpandAll(string[] nodesId = null)
Parameters
Type Name Description
System.String[] nodesId
Returns
Type Description
System.Threading.Tasks.Task

GetAllCheckedNodes()

Gets all the checked nodes including child, whether it is loaded or not.

Declaration
public Task<List<string>> GetAllCheckedNodes()
Returns
Type Description
System.Threading.Tasks.Task<System.Collections.Generic.List<System.String>>

GetDisabledNodes()

Gets all the disabled nodes including child, whether it is loaded or not.

Declaration
public Task<List<string>> GetDisabledNodes()
Returns
Type Description
System.Threading.Tasks.Task<System.Collections.Generic.List<System.String>>

GetNode(String)

Get the node's data such as id, text, parentID, selected, isChecked, and expanded by passing the node element or it's ID.

Declaration
public NodeData GetNode(string node)
Parameters
Type Name Description
System.String node

Specifies ID of TreeView node.
Returns
Type Description
NodeData

GetPropertyChanges()

Declaration
protected IDictionary<string, object> GetPropertyChanges()
Returns
Type Description
System.Collections.Generic.IDictionary<System.String, System.Object>

GetRootElement()

Returns the route element reference of the component

Declaration
public ElementReference GetRootElement()
Returns
Type Description
Microsoft.AspNetCore.Components.ElementReference

GetTreeData(String)

To get the updated data source of TreeView after performing some operation like drag and drop, node editing, node selecting/unSelecting, node expanding/collapsing, node checking/unChecking, adding and removing node. If you pass the ID of TreeView node as arguments for this method then it will return the updated data source of the corresponding node otherwise it will return the entire updated data source of TreeView. The updated data source also contains custom attributes if you specified in data source.

Declaration
public List<TValue> GetTreeData(string node = null)
Parameters
Type Name Description
System.String node

Specifies ID of TreeView node.
Returns
Type Description
System.Collections.Generic.List<TValue>

MoveNodes(String[], String, Int32, Nullable<Boolean>)

Replaces the text of the TreeView node with the given text.

Declaration
public Task MoveNodes(string[] sourceNodes, string target, int index, Nullable<bool> preventTargetExpand)
Parameters
Type Name Description
System.String[] sourceNodes

Specifies the array of TreeView nodes ID.
System.String target

Specifies ID of TreeView node.
System.Int32 index

Specifies the index to place the moved nodes in the target element.
System.Nullable<System.Boolean> preventTargetExpand

If set to true, the target parent node will be prevented from auto expanding.
Returns
Type Description
System.Threading.Tasks.Task

OnAfterRenderAsync(Boolean)

Declaration
protected override Task OnAfterRenderAsync(bool firstRender)
Parameters
Type Name Description
System.Boolean firstRender
Returns
Type Description
System.Threading.Tasks.Task
Overrides
Syncfusion.Blazor.SfBaseComponent.OnAfterRenderAsync(System.Boolean)

OnInitializedAsync()

Declaration
protected override Task OnInitializedAsync()
Returns
Type Description
System.Threading.Tasks.Task
Overrides
Syncfusion.Blazor.SfBaseComponent.OnInitializedAsync()

OnParametersSetAsync()

Declaration
protected override Task OnParametersSetAsync()
Returns
Type Description
System.Threading.Tasks.Task

Refresh()

Applies all the pending property changes and render the component again.

Declaration
public Task Refresh()
Returns
Type Description
System.Threading.Tasks.Task

RefreshNode(String, List<TValue>)

Replaces the text of the TreeView node with the given text.

Declaration
public Task RefreshNode(string target, List<TValue> newData)
Parameters
Type Name Description
System.String target

Specifies ID of TreeView node.
System.Collections.Generic.List<TValue> newData

Specifies the new Data of TreeView node.
Returns
Type Description
System.Threading.Tasks.Task

RemoveNodes(String[])

Removes the collection of TreeView nodes by passing the array of node details as argument to this method.

Declaration
public Task RemoveNodes(string[] nodes)
Parameters
Type Name Description
System.String[] nodes

Specifies the array of TreeView nodes ID.
Returns
Type Description
System.Threading.Tasks.Task

TriggerKeyboardEvent(NodeKeyPressEventArgs, String, String, String)

Collapsed Action for TreeView

Declaration
public Task TriggerKeyboardEvent(NodeKeyPressEventArgs args, string id, string keyAction, string keyValue)
Parameters
Type Name Description
NodeKeyPressEventArgs args
System.String id
System.String keyAction
System.String keyValue
Returns
Type Description
System.Threading.Tasks.Task

TriggerNodeCollapsedEvent(NodeExpandEventArgs)

Collapsed Action for TreeView

Declaration
public Task TriggerNodeCollapsedEvent(NodeExpandEventArgs args)
Parameters
Type Name Description
NodeExpandEventArgs args
Returns
Type Description
System.Threading.Tasks.Task

TriggerNodeCollapsingEvent(NodeExpandEventArgs)

Collapse Action for TreeView

Declaration
public Task TriggerNodeCollapsingEvent(NodeExpandEventArgs args)
Parameters
Type Name Description
NodeExpandEventArgs args
Returns
Type Description
System.Threading.Tasks.Task

UncheckAll(String[])

Unchecks all the checked nodes. You can also uncheck the specific nodes by passing array of checked nodes as argument to this method.

Declaration
public Task UncheckAll(string[] nodesId = null)
Parameters
Type Name Description
System.String[] nodesId
Returns
Type Description
System.Threading.Tasks.Task

UpdateChildProperties(String, Object)

Declaration
public void UpdateChildProperties(string key, object details)
Parameters
Type Name Description
System.String key
System.Object details

UpdateData(List<TValue>, Boolean)

Update the latest data source values to TreeView component (Drag and drop)

Declaration
public Task UpdateData(List<TValue> dataSource, bool IsUpdateChecked = false)
Parameters
Type Name Description
System.Collections.Generic.List<TValue> dataSource
System.Boolean IsUpdateChecked
Returns
Type Description
System.Threading.Tasks.Task

UpdateNode(String, String)

Replaces the text of the TreeView node with the given text.

Declaration
public Task UpdateNode(string target, string newText)
Parameters
Type Name Description
System.String target

Specifies ID of TreeView node.
System.String newText

Specifies the new text of TreeView node.
Returns
Type Description
System.Threading.Tasks.Task