Installation

Step 1

Install the NuGet Package

Install via the .NET CLI:

dotnet add package RichTextBox

Or via the Visual Studio Package Manager Console:

Install-Package RichTextBox

Or add directly to your .csproj:

<PackageReference Include="RichTextBox" Version="1.0.0-preview.1" />

Step 2

Configure Program.cs

Register the RichTextBox services and map the upload endpoints. You can customize the upload path, allowed extensions, and maximum file size.

var builder = WebApplication.CreateBuilder(args);

// Register RichTextBox services with default options
builder.Services.AddRichTextBox();

// Or with custom options:
builder.Services.AddRichTextBox(options =>
{
    options.UploadWebPath = "/uploads";
    options.MaxUploadBytes = 4 * 1024 * 1024; // 4 MB
    options.AllowedImageExtensions = new[] { ".jpg", ".jpeg", ".png", ".gif", ".webp", ".svg" };
    options.AllowedFileExtensions = new[] { ".zip", ".pdf", ".doc", ".docx" };
});

var app = builder.Build();
app.UseStaticFiles();

// Map upload and gallery endpoints
app.MapRichTextBoxUploads();

app.MapRazorPages();
app.Run();

Step 3

Register the Tag Helper

Add the RichTextBox Tag Helper to your Pages/_ViewImports.cshtml:

@addTagHelper *, Microsoft.AspNetCore.Mvc.TagHelpers
@addTagHelper *, RichTextBox

Step 5

Create the Upload Directory

Create a wwwroot/uploads folder for image uploads. The gallery endpoint will browse and upload images into this directory.

mkdir wwwroot/uploads

On deployed servers, ensure the application pool identity has write access to this folder.

Step 6

Verify the Installation

Add a simple editor to any page and run your application:

<richtextbox name="Body" toolbar="default" height="300px" />

If the editor renders with a toolbar, your installation is complete. If you see a license error, verify that RichTextBox.lic is in the content root and the license number matches.

Step 7

Files deployed to wwwroot

The NuGet package copies the static web assets into your site's wwwroot/richtexteditor/ at publish time. For a 2.0 deployment the notable additions are:

• • plugins/aitoolkit.js — Ask AI dropdown + docked AI Chat + AI Review drawer.
• • plugins/aitoolkit.css — AI Toolkit styles (required alongside aitoolkit.js).
• • plugins/structured-content-bridge.js — window.RichTextEditorStructuredContent helpers (fromMarkdown, toMarkdown, renderHTML, validateStructuredContent).
• • rte.js — includes the rte-config.js defaults block at the top. Edit RTE_DefaultConfig values directly to change every editor on the site without rebuilding.

AI Toolkit: BYOK pattern. The default resolver is a local demo that needs no API key. For production, register an IRichTextBoxAiResolver with dependency injection (server-side) or swap the resolver on the client via editor.aiToolkit.setResolver(fn). Your resolver calls your own backend (which holds the provider API key in its secrets store) and returns { result, reason, operations }. See the BYOK demo.