MediatR Navigation Extension (Visual Studio 2022+)

Bidirectional navigation between MediatR requests, handlers, and call sites — plus CodeLens showing handler and usage counts inline.

Commands

Commands are context-aware — only the relevant command appears based on cursor position.

Go to MediatR Implementation

Go to MediatR Send/Publish

Features

Go to MediatR Implementation (Request → Handler)

• Detects IRequest, IRequest<T>, and INotification implementations
• Navigates directly to the handler's Handle/Execute method signature
• Multi-handler selection dialog when multiple handlers exist
• Also works when cursor is on a nested _mediator.Send(new MyQuery()) call inside a handler

Go to MediatR Send/Publish (Handler → Usage)

• Finds all Send(), SendAsync(), Publish(), and PublishAsync() call sites in the solution
• Detects usages through IMediator, ISender, and IPublisher interfaces
• Handles direct instantiation, variable references, and conditional access (?.) patterns
• Multi-usage selection dialog with Send vs Publish grouping

CodeLens

• Shows handler count and usage count inline above every MediatR type declaration
• Also shows on individual Handle, Execute, and Process method signatures
• Click to expand a detail pane listing all handlers and usages with file and line info
• Configurable via Tools → Options → MediatR Navigation

Smart Context Detection

• Commands appear only when the cursor is on a relevant MediatR symbol
• Works on request/notification classes, handler classes, handler methods, and nested Send/Publish calls

Supported MediatR Patterns

Request types

• IRequest — command without response
• IRequest<TResponse> — query with response
• INotification — event/notification
• A single class implementing both IRequest and INotification

Handler types

Usage patterns detected

• _mediator.Send(new MyRequest())
• _mediator.SendAsync(request)
• _mediator.Publish(new MyNotification())
• _mediator.PublishAsync(notification)
• _mediator?.Send(...) (conditional access)
• Variable and field references passed to Send/Publish

Usage

Request → Handler

1. Position cursor on a MediatR request/command/query/notification class name
2. Press Ctrl+Alt+F12, or use Edit menu, or right-click context menu
3. If multiple handlers exist, a selection dialog appears

Handler → Usage

1. Position cursor on a handler class name or inside a Handle/Execute method
2. Press Ctrl+Alt+F11, or use Edit menu, or right-click context menu
3. If multiple usages exist, a selection dialog appears

Nested navigation

When inside a handler method that contains a nested _mediator.Send(new OtherQuery()) call:

• Ctrl+Alt+F12 navigates to OtherQuery's handler
• Ctrl+Alt+F11 navigates to where the current handler's request is sent

Settings

Tools → Options → MediatR Navigation

Item Templates

Add New Item → MediatR — four scaffolding templates:

• MediatR Command — IRequest class
• MediatR Handler — IRequestHandler<T> class
• MediatR Notification — INotification class
• MediatR Notification Handler — INotificationHandler<T> class

Requirements

• Visual Studio 2022–2026 (17.0–19.0)
• .NET Framework 4.7.2+
• Project references MediatR

Installation

Install from the Visual Studio Marketplace or via Extensions → Manage Extensions (search "MediatR Navigation").

Troubleshooting

Commands not appearing: Ensure you're in a C# file, the caret is on a relevant symbol, the solution builds, and MediatR is referenced.

Handler not found: Rebuild the solution; verify the handler implements the correct interface and is in the same solution.

Usage not found: Confirm the request is sent via _mediator.Send() or _mediator.Publish(); rebuild the solution.

License

MIT