uno-mvux-listfeed

# MVUX ListFeed — 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 ListFeed Reference Documentation Search for and fetch the documentation: ``` uno_platform_docs_search("MVUX ListFeed reactive collection IListFeed") ``` Primary documentation pages: - **ListFeed Reference**: `external/uno.extensions/doc/Reference/Reactive/listfeed.md` - **ListFeed How-To**: `external/uno.extensions/doc/Learn/Mvux/Walkthrough/ListFeed.howto.md` Fetch the full reference: ``` uno_platform_docs_fetch(sourcePath="external/uno.extensions/doc/Reference/Reactive/listfeed.md") ``` ### Step 2: Learn ListFeed Creation Methods From the fetched docs, the key factory methods on the `ListFeed` static class: - `ListFeed.Async(...)` — from a method returning `Task<IImmutableList<T>>` - `ListFeed.AsyncEnumerable(...)` — from an `IAsyncEnumerable<IImmutableList<T>>` - `ListFeed.PaginatedAsync(...)` — for paginated/infinite scroll (see `uno-mvux-pagination` skill) ### Step 3: For ListFeed Operators The reference page covers operators like `Where`, `Select`, and `AsFeed`. These operate on individual items in the collection. ### Step 4: For How-To Walkthroughs For step-by-step examples: ``` uno_platform_docs_fetch(sourcePath="external/uno.extensions/doc/Learn/Mvux/Walkthrough/ListFeed.howto.md") ``` This covers loading a list, showing it with FeedView, filtering with `Where`, and when to use feeds vs states. ### Step 5: For Displaying Lists in XAML The how-to page shows how to bind `IListFeed<T>` to `ListView` via `FeedView` and access items through `{Binding Data}`. ## Key Principles (Stable) - `IListFeed<T>` is **read-only** — use `IListState<T>` for add/remove/update - Service methods should return `ValueTask<IImmutableList<T>>` (from `System.Collections.Immutable`) - Operators like `Where` and `Select` work on individual items, not the list itself - ListFeed automatically handles loading/error/empty states - Use `IListFeed<T>` when data is pulled from a service and is read-only - Use `IListState<T>` when you need to edit the collection client-side ## Key Equality Requirement (Critical) **All item types used in `IListFeed<T>` MUST support key equality** via `Uno.Extensions.Equality.IKeyEquatable<T>`. Without key equality, MVUX cannot distinguish between a modified entity and a completely different one, causing full list re-renders instead of granular item updates (flickering, lost scroll position, broken animations). ### Automatic generation (recommended) For `partial record` types, key equality is **auto-generated** when the record has a property named `Id` or `Key`: ```csharp public partial record Person(Guid Id, string Name, int Age); // IKeyEquatable<Person> is generated automatically — Id is the key ``` ### Explicit key configuration Use `[Key]` attribute when the key property has a different name, or for composite keys: ```csharp public partial record OrderLine( [property: Key] Guid OrderId, [property: Key] int LineNumber, string Product, decimal Price); ``` Either `Uno.Extensions.Equality.KeyAttribute` or `System.ComponentModel.DataAnnotations.KeyAttribute` can be used. ### Assembly-level defaults Configure which property names are auto-detected as keys: ```csharp [assembly: ImplicitKeyEquality("Id", "Key", "EntityId")] ``` ### Disabling generation If auto-generation causes issues on a specific type: ```csharp [ImplicitKeys(IsEnabled = false)] public partial record MyItem(Guid Id, string Name); ``` ### Rules - The item type **must** be a `partial record` (or manually implement `IKeyEquatable<T>`) - At least one key property is required — without it, every update replaces the entire list in the UI - Key properties define **identity** (same entity); non-key properties define **state** (changed data) - `KeyEquals` returns `true` when two instances represent the same entity, even if other properties differ ## Related Skills - [[uno-mvux-feed-basics]] — Single-value feeds - [[uno-mvux-liststate]] — Mutable reactive collections - [[uno-mvux-selection]] — Selection management with list feeds - [[uno-mvux-pagination]] — Infinite scroll / paginated lists - [[uno-mvux-feedview]] — Displaying feed data in XAML