Syncfusion ASP.NET Core Block Editor Control

Overview

A comprehensive skill for implementing Syncfusion EJ2 Block Editor in ASP.NET Core applications using Razor Tag Helpers. This skill covers setup, block configuration, content manipulation, events, and best practices for creating block-based document editors.

The Syncfusion Block Editor is a versatile, block-based content editor that allows users to create and edit structured documents using discrete content blocks. Key capabilities include:

• Multiple Block Types: Paragraph, Headings (1-4), Lists (Bullet, Numbered, Checklist), Code, Tables, Images, Quotes, Callouts, and more
• Nested Structures: Support for collapsible headings, quotes, and callouts with child blocks
• Rich Editor Menus: Slash commands, context menus, inline toolbars, and block action menus
• Drag-and-Drop: Reorder blocks seamlessly with visual feedback
• Content Sanitization: Built-in paste cleanup with configurable denied tags
• Keyboard Shortcuts: Comprehensive shortcuts for formatting, block creation, and management
• Undo/Redo: Configurable undo/redo stack (default 30 actions)
• Globalization: Multi-language support and RTL layout support
• Events: Rich event system for monitoring user interactions and content changes
• Responsive Design: Adaptive UI that works on desktop and mobile devices
• Collaborative Editing: Real-time multi-user document editing with Yjs CRDT framework, remote cursor awareness, user presence tracking, and version history management

Documentation and Navigation Guide

Getting Started

📄 Read: references/getting-started.md

• Installation and package setup
• Basic BlockEditor implementation
• CSS imports and theme selection
• Creating the first Block Editor instance
• Setting initial block content

Built-in Blocks

📄 Read: references/built-in-blocks.md

• Block types overview (Paragraph, Heading, Lists, Code, Table, Embed, etc.)
• Block properties (id, blockType, content, indent)
• Nested block types (CollapsibleHeading, CollapsibleParagraph, Quote, Callout)
• Parent-child relationships and hierarchy
• Expanded state control and placeholders
• CSS class customization and templates

Block Editor Menus

📄 Read: references/blockeditor-menus.md

• Inline toolbar configuration and events
• Block actions menu customization
• Slash commands (/) for quick block insertion
• Context menu configuration
• Toolbar buttons and formatting actions

Drag-Drop and Content

📄 Read: references/drag-drop-and-content.md

• Enable drag-and-drop functionality
• Reordering blocks by dragging
• Multiple block selection and movement
• Visual feedback during drag operations
• Content insertion and block positioning

Methods and API

📄 Read: references/methods-and-api.md

• Block Management: addBlock, removeBlock, moveBlock, updateBlock, getBlock, getBlockCount
• Selection & Cursor: setSelection, setCursorPosition, getSelectedBlocks, getRange, selectRange, selectBlock, selectAllBlocks
• Focus Management: focusIn, focusOut
• Formatting: executeToolbarAction, enableToolbarItems, disableToolbarItems
• Data Export: getDataAsJson, getDataAsHtml, renderBlocksFromJson, parseHtmlToBlocks, print
• Practical examples for each method category

Styling and Appearance

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

• CSS theming options (Material, Bootstrap, Fluent, Tailwind, Fabric themes)
• Block-level styling and cssClass property
• Typography options (bold, italic, underline, strikethrough)
• Indentation and nested block styling
• Placeholder text customization
• Dark mode support and custom themes

Advanced Features

📄 Read: references/advanced-features.md

• Paste cleanup and content sanitization (denied tags)
• Keep format and plain text modes
• Undo/Redo functionality and stack configuration
• Keyboard shortcuts and customization
• Read-only mode for view-only editors
• XSS protection and HTML sanitizer
• RTL (Right-to-Left) support
• Globalization and multi-language localization

Collaborative Editing

📄 Read: references/collaborative-editing.md

• Real-time multi-user document editing with Yjs provider integration
• Configuring collaboration adapters and providers (y-websocket, y-webrtc, Hocuspocus, Liveblocks, PartyKit)
• User presence and remote cursor visualization with enableAwareness
• Active user tracking and user configuration with avatarBgColor
• Version history management with snapshots, restore, compare, export, and import operations
• Snapshot lifecycle events (snapshotCreated, snapshotRestored)
• Best practices for development and production deployments
• Troubleshooting collaboration issues

Quick Start Example

Basic Block Editor Setup

Step 1: Install NuGet Package

Install-Package Syncfusion.EJ2.AspNet.Core

Step 2: Register in _ViewImports.cshtml

@addTagHelper *, Syncfusion.EJ2

Step 3: Add CSS and Scripts in _Layout.cshtml

<head>
    <link rel="stylesheet" href="https://cdn.syncfusion.com/ej2/dist/ej2.min.css" />
</head>
<body>
    @RenderBody()
    
    <script src="https://cdn.syncfusion.com/ej2/dist/ej2.min.js"></script>
    <ejs-scripts></ejs-scripts>
    
    @RenderSection("Scripts", required: false)
</body>

Step 4: Create Block Editor in View

@using Syncfusion.EJ2.BlockEditor

<div id='blockeditor-container'>
    <ejs-blockeditor id="block-editor" blocks="@ViewBag.BlocksData"></ejs-blockeditor>
</div>

<style>
    #blockeditor-container {
        margin: 20px auto;
    }
</style>

Step 5: Configure Blocks in Controller

using Syncfusion.EJ2.BlockEditor;

public class BlockModel
{
    public string id { get; set; }
    public string blockType { get; set; }
    public object properties { get; set; }
    public List<object> content { get; set; }
}

public IActionResult Index()
{
    var blocks = new List<BlockModel>
    {
        new BlockModel
        {
            id = "heading-1",
            blockType = "Heading",
            properties = new { level = 1 },
            content = new List<object>
            {
                new { contentType = "Text", content = "Welcome to Block Editor" }
            }
        },
        new BlockModel
        {
            id = "paragraph-1",
            blockType = "Paragraph",
            content = new List<object>
            {
                new { contentType = "Text", content = "Start creating your content with blocks!" }
            }
        }
    };
    
    ViewBag.BlocksData = blocks;
    return View();
}

Common Patterns

Pattern 1: Add New Block Dynamically

var blockEditorObj = ej.base.getInstance(document.getElementById('block-editor'), ejs.blockeditor.BlockEditor);

const newBlock = {
    id: 'new-paragraph',
    blockType: 'Paragraph',
    content: [
        {
            contentType: "Text",
            content: 'This is a newly added block'
        }
    ]
};

// Add after a specific block
blockEditorObj.addBlock(newBlock, 'existing-block-id', true);

Pattern 2: Nested Collapsible Structure

new BlockModel
{
    blockType = "CollapsibleHeading",
    content = new List<object>
    {
        new { contentType = "Text", content = "Section Title" }
    },
    properties = new
    {
        level = 1,
        isExpanded = true,
        children = new List<BlockModel>
        {
            new BlockModel
            {
                blockType = "Paragraph",
                content = new List<object>
                {
                    new { contentType = "Text", content = "Hidden content goes here" }
                }
            }
        }
    }
}

Pattern 3: Configure Paste Cleanup

<ejs-blockeditor id="block-editor">
    <e-blockeditor-pastesettings 
        deniedTags="@(new string[] { "script", "iframe", "form" })"
        keepFormat="true">
    </e-blockeditor-pastesettings>
</ejs-blockeditor>

Pattern 4: Custom Slash Commands

var commandMenuItems = new List<object>
{
    new 
    {
        id = "timestamp",
        groupHeader = "Actions",
        label = "Insert Timestamp",
        iconCss = "e-icons e-schedule"
    },
    new 
    {
        id = "separator",
        type = "Divider",
        groupHeader = "Utility",
        label = "Insert Divider",
        iconCss = "e-icons e-divider"
    }
};

ViewBag.CommandMenuItems = commandMenuItems;

Pattern 5: Readonly Editor for Display

<ejs-blockeditor id="block-editor" 
                 readOnly="true" 
                 blocks="@ViewBag.BlocksData">
</ejs-blockeditor>

Key Properties

Common Use Cases

1. Blog Post Editor - Create a structured blog editor with headings, paragraphs, lists, code snippets, and images
2. Knowledge Base - Build hierarchical documentation with collapsible sections and nested content
3. Newsletter Template Builder - Design email templates with predefined blocks
4. Content Management System - Manage modular content with drag-and-drop block reordering
5. Documentation Platform - Create technical documentation with code blocks, tables, and callouts
6. Form Builder - Create dynamic forms with conditional block visibility
7. Collaborative Editing - Implement shared document editing with block-level permissions

Workflow Pattern

When implementing a Syncfusion Block Editor in ASP.NET Core:

1. Install and Setup - Follow Getting Started guide for package installation and registration
2. Define Block Structure - Choose block types and configure them in references/built-in-blocks.md
3. Initialize Editor - Create Block Editor instance with initial blocks
4. Configure Features - Enable menus, drag-drop, paste cleanup as needed
5. Handle Events - Bind to events for content validation, logging, or integration
6. Customize Appearance - Apply CSS themes, custom classes, and styling
7. Implement Methods - Use API methods for programmatic content manipulation
8. Test and Optimize - Verify functionality and performance