uno-mvux-messaging

name	uno-mvux-messaging
description	Use messaging to sync MVUX states with entity changes.
when_to_use	Use when CRUD operations that should update all views showing the same data, decoupling services from models — services broadcast changes, models react, keeping multiple views/pages in sync when shared entities change, or using `EntityMessage<T>` with CommunityToolkit.Mvvm messenger.
metadata	{"author":"uno-platform","version":"2.3","category":"mvux"}

MVUX Messaging — Agent Skill

Workflow

Docs lookup: call uno_platform_docs_search(...) first, then uno_platform_docs_fetch(sourcePath="…") using the sourcePath field from a result (a relative .md path; add the result's anchor for a section). Never pass a URL, a .html link, or a hand-built path.

Step 1: Fetch the Messaging Documentation

Search for and fetch the messaging documentation:

uno_platform_docs_search("MVUX messaging EntityMessage synchronization CRUD")

Primary documentation pages:

• Messaging Reference: external/uno.extensions/doc/Learn/Mvux/Advanced/Messaging.md
• Messaging How-To: external/uno.extensions/doc/Learn/Mvux/Walkthrough/Messaging.howto.md

Fetch the reference page:

uno_platform_docs_fetch(sourcePath="external/uno.extensions/doc/Learn/Mvux/Advanced/Messaging.md")

Step 2: For How-To Walkthroughs

For step-by-step implementation:

uno_platform_docs_fetch(sourcePath="external/uno.extensions/doc/Learn/Mvux/Walkthrough/Messaging.howto.md")

This covers when to use messaging, sending entity messages from services, observing changes in models, and manual message handling.

Step 3: Understand the Architecture

From the fetched docs, the messaging pattern involves:

1. Service sends EntityMessage<T> via IMessenger.Send(...)
2. Model uses .Observe(messenger) on a ListState to auto-apply changes
3. Entity changes (Created/Updated/Deleted) are applied to the matching state

Step 4: For Manual Message Handling

If the user needs custom logic when messages arrive, the reference page covers the Update extension methods that allow manual application of EntityMessage<T> to states.

Key Principles (Stable)

• Register IMessenger as a singleton in DI: services.AddSingleton<IMessenger, WeakReferenceMessenger>()
• EntityMessage<T> carries an entity change type (Created, Updated, Deleted) and the entity
• .Observe(messenger) on a ListState auto-applies incoming entity changes
• Records need key equality for matching (see uno-mvux-records skill)
• Namespace: Uno.Extensions.Reactive.Messaging

Related Skills

• [[uno-mvux-liststate]] — Mutable collections that messaging updates
• [[uno-mvux-records]] — Key equality for entity matching
• [[uno-mvux-commands]] — Commands that trigger CRUD operations