syncfusion-aspnetcore-tree-view

name	syncfusion-aspnetcore-tree-view
description	Implement the Syncfusion ASP.NET Core TreeView component for hierarchical data visualization. Use this when working with tree structures, node selection, checkboxes, or drag-and-drop operations. This skill covers data binding, node editing, and advanced tree configurations.
metadata	{"author":"Syncfusion Inc","version":"34.1.29","category":"Navigation Components"}

Implementing Syncfusion Core TreeView

When to Use This Skill

Use this skill when you need to:

• Display hierarchical data structures - Render organizational charts, file systems, category trees, or any nested data in a tree format
• Enable user selection - Implement single or multi-select functionality with keyboard and mouse interactions
• Build interactive trees - Add drag-and-drop, node editing, checkboxes, and dynamic node manipulation
• Customize appearance - Apply templates, icons, animations, and styling to match your application design
• Handle tree events - Respond to node interactions with expand/collapse, selection, and editing events
• Implement load-on-demand - Optimize performance for large datasets by loading child nodes only when parent nodes expand
• Create accessibility-compliant interfaces - Ensure keyboard navigation and screen reader support for users with accessibility needs

Component Overview

The Syncfusion TreeView is an enterprise-grade component that displays hierarchical data in a tree structure with powerful interactive features. It supports local and remote data binding, multiple selection modes, drag-and-drop operations, node editing, checkboxes, and comprehensive event handling.

Key Capabilities

• Data Binding: Support for hierarchical data, self-referential data, local arrays, and remote data services (OData, Web API, DataManager)
• Node Interactions: Single selection, multi-selection (Ctrl/Shift keys), keyboard navigation (arrow keys, F2, Delete)
• Selection Types: Full row selection, node text selection, checkbox selection, independent node states
• Dynamic Operations: Add, remove, update, refresh, and move nodes programmatically
• Editing: In-place editing with double-click or F2 key, with validation support
• Drag-and-Drop: Full drag-and-drop support with visual indicators and multi-node dragging
• Checkboxes: Parent-child dependency, auto-check propagation, independent states
• Customization: Node templates, custom icons, CSS styling, animation effects
• Performance: Load-on-demand rendering for large datasets, lazy loading of child nodes
• Accessibility: Full keyboard support, ARIA attributes, screen reader compatibility

Documentation and Navigation Guide

Use this guide to navigate to the specific TreeView feature you need to implement:

Getting Started

📄 Read: references/getting-started.md

When you need to:

• Set up TreeView in your application for the first time
• Understand basic component initialization and configuration
• Learn prerequisite setup and installation steps
• See your first working TreeView example

Data Binding and Field Configuration

📄 Read: references/data-binding-and-fields.md

When you need to:

• Bind data from local arrays or remote services
• Configure hierarchical or self-referential data structures
• Map data source fields to TreeView properties
• Implement remote data binding with DataManager
• Handle load-on-demand scenarios

Node Selection (Single and Multi-Select)

📄 Read: references/node-selection.md

When you need to:

• Enable single node selection
• Implement multi-selection with Ctrl and Shift keys
• Track selected nodes programmatically
• Respond to selection events
• Prevent selection for specific nodes

Node Expansion and Collapsing

📄 Read: references/node-expansion.md

When you need to:

• Control node expand/collapse behavior
• Configure expand-on-click or double-click
• Handle expand/collapse events
• Manage expanded nodes state
• Implement load-on-demand expansion

Checkboxes and Checked Nodes

📄 Read: references/checkboxes-and-checked-nodes.md

When you need to:

• Enable checkboxes in TreeView nodes
• Track checked nodes and their states
• Implement auto-check for parent-child relationships
• Configure independent node check states
• Handle checkbox change events

Drag and Drop Operations

📄 Read: references/drag-and-drop.md

When you need to:

• Enable drag-and-drop functionality
• Handle single and multi-node dragging
• Control drop zones and restrictions
• Respond to drag-drop lifecycle events
• Prevent dragging for specific nodes

Node Editing and Validation

📄 Read: references/node-editing.md

When you need to:

• Enable in-place node text editing
• Implement edit mode with double-click or F2
• Validate node text during editing
• Prevent editing for specific nodes
• Save or cancel edit operations

Templates and Styling

📄 Read: references/templates-and-styling.md

When you need to:

• Customize node appearance with templates
• Apply custom icons and images
• Configure animations and transitions
• Implement full-row selection styling
• Use CSS classes for TreeView customization

Node Manipulation and Dynamic Operations

📄 Read: references/node-manipulation.md

When you need to:

• Add new nodes programmatically
• Remove existing nodes
• Update node text or properties
• Refresh node content
• Move nodes to different positions
• Get tree data programmatically

Events and Keyboard Navigation

📄 Read: references/events-and-keyboard-navigation.md

When you need to:

• Handle all TreeView events (expand, select, check, drag, edit)
• Implement keyboard navigation support
• Respond to user interactions
• Prevent default behavior for specific actions
• Track component lifecycle events

Complete API Reference

📄 Read: references/api-reference.md

When you need to:

• Look up specific property definitions and default values
• Find method signatures with parameter descriptions
• Understand event handler parameters and structure
• Reference FieldsSettings configuration options
• Check AnimationSettings for expand/collapse effects
• Get complete API documentation with code examples for all properties, methods, and events

Quick Start Example

Here's a minimal example to get TreeView running immediately:

<ejs-treeview id="treeAdvanced" showCheckBox="true" 
    allowMultiSelection="true" allowDragAndDrop="true" allowEditing="true">
    <e-treeview-fields dataSource="ViewBag.dataSource" id="id" parentId="pid" text="name" hasChildren="hasChild"></e-treeview-fields>
</ejs-treeview>

Common Patterns

Pattern 1: Single Selection with Event Handling

<ejs-treeview id="treeAdvanced" allowMultiSelection="false">
    <e-treeview-fields dataSource="ViewBag.dataSource" id="id" parentId="pid" text="name" hasChildren="hasChild"></e-treeview-fields>
</ejs-treeview>

Pattern 2: Multi-Select with Checkboxes

<ejs-treeview id="treeAdvanced" showCheckBox="true" 
    allowMultiSelection="true">
    <e-treeview-fields dataSource="ViewBag.dataSource" id="id" parentId="pid" text="name" hasChildren="hasChild"></e-treeview-fields>
</ejs-treeview>

Pattern 3: Lazy Loading with Load-on-Demand

<ejs-treeview id="treeAdvanced" loadOnDemand="true">
    <e-treeview-fields dataSource="ViewBag.dataSource" id="id" parentId="pid" text="name" hasChildren="hasChild"></e-treeview-fields>
</ejs-treeview>

Pattern 4: Editable Tree with Validation

<ejs-treeview id="treeRestricted" allowEditing="true" nodeEditing="nodeEditing" nodeEdited="nodeEdited">
    <e-treeview-fields dataSource="ViewBag.dataSource" id="id" text="name"></e-treeview-fields>
</ejs-treeview>

<script>
    function nodeEditing(args) {
        if (args.newText.length < 3) {
          args.cancel = true;
        }
    }
    function nodeEdited(args) {
      console.log('Node text updated to:', args.newText);
    }
</script>

Pattern 5: Drag-Drop with Restrictions

<ejs-treeview id="treeNodeDrag" allowDragAndDrop="true" 
    nodeDragStart="onDragStart" 
    nodeDropped="nodeDropped">
    <e-treeview-fields dataSource="ViewBag.dataSource" id="id" text="name"></e-treeview-fields>
</ejs-treeview>

<script>
    function onDragStart(args) {
      if (!args.nodeData.pid) {
          args.cancel = true;
      }
    }
    
    function nodeDropped(args) {
        console.log('Node dropped successfully');
    }
</script>

Key Props Reference

Property	Type	Default	Purpose
fields	FieldsSettings	-	Configure data source and field mappings
dataSource	array | DataManager	[]	Data source for TreeView nodes
showCheckBox	boolean	false	Show checkboxes for node selection
allowMultiSelection	boolean	false	Enable multi-node selection
allowDragAndDrop	boolean	false	Enable drag-and-drop operations
allowEditing	boolean	false	Enable in-place node editing
allowTextWrap	boolean	false	Wrap node text for overflow
loadOnDemand	boolean	true	Load child nodes on parent expand
fullRowSelect	boolean	false	Select entire row instead of text
fullRowNavigable	boolean	false	Navigate entire row with keyboard
expandOn	string	'Click'	Action to expand/collapse (Click, DblClick, None)
sortOrder	string	'None'	Sort nodes (None, Ascending, Descending)
selectedNodes	string[]	[]	Selected node IDs
checkedNodes	string[]	[]	Checked node IDs
expandedNodes	string[]	[]	Expanded node IDs
cssClass	string	''	Custom CSS classes
disabled	boolean	false

Common Use Cases

Use Case 1: File Manager Tree

Display a hierarchical file system with folders and files, enabling users to browse, select, and manage files.

Key Features: Hierarchical data, icons for file/folder types, multi-select, drag-drop for moving files, context menu for operations.

Related References: data-binding-and-fields.md, templates-and-styling.md, drag-and-drop.md

Use Case 2: Organizational Chart

Show company hierarchy with employees organized by departments and teams.

Key Features: Hierarchical data, node templates for employee details, search/filter, single selection, expand/collapse.

Related References: data-binding-and-fields.md, templates-and-styling.md, node-selection.md

Use Case 3: Permission/Role Management

Display hierarchical permissions or roles where users select multiple permissions for roles.

Key Features: Checkboxes, multi-select, parent-child dependency, auto-check propagation, checkbox events.

Related References: checkboxes-and-checked-nodes.md, node-selection.md

Use Case 4: Product Category Browser

Browse product categories with filtering and search capability.

Key Features: Large dataset with load-on-demand, single selection, keyboard navigation, expand-on-click.

Related References: data-binding-and-fields.md, node-expansion.md, events-and-keyboard-navigation.md

Use Case 5: Menu Structure Editor

Allow administrators to create and edit hierarchical menu structures.

Key Features: Node editing, add/remove/move nodes, templates, drag-drop, in-place editing with validation.

Related References: node-manipulation.md, node-editing.md, templates-and-styling.md

Summary

The Syncfusion TreeView component provides a complete solution for displaying and interacting with hierarchical data. It combines powerful data binding capabilities with rich interactive features like multi-selection, drag-and-drop, editing, and checkboxes. With extensive customization options through templates and styling, you can create sophisticated tree-based interfaces that meet any business requirement.

Start with the Getting Started reference to set up your first TreeView, then explore specific features using the documentation guide above based on your requirements.

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Next Steps: Choose your first task from the Documentation and Navigation Guide section and follow the reference guide to implement your TreeView feature.