ZeroAlloc.Notify 1.2.2

ZeroAlloc.Notify

ZeroAlloc.Notify is a source-generated notification library for .NET 8 and .NET 10. It provides async-first property and collection change notifications without reflection or dynamic dispatch. The Roslyn source generator eliminates runtime overhead by wiring all dispatch at compile time — no virtual dispatch, fully awaitable handlers.

Install

The source generator is bundled into the main package — a single PackageReference is all you need:

dotnet add package ZeroAlloc.Notify

The standalone ZeroAlloc.Notify.Generator package is still published for backwards compatibility with existing direct PackageReferences, but new consumers should reference only ZeroAlloc.Notify.

Quick Example

// 1. Define a ViewModel with observable properties
[NotifyPropertyChangedAsync]
public partial class UserViewModel
{
    [ObservableProperty]
    private string _name = "";

    [ObservableProperty]
    private int _age;
}

// 2. Subscribe to async notifications
var vm = new UserViewModel();
vm.PropertyChangedAsync += async (args, ct) =>
{
    Console.WriteLine($"Property '{args.PropertyName}' changed from {args.OldValue} to {args.NewValue}");
    await Task.Delay(100, ct); // Non-blocking handler execution
};

// 3. Set properties — fully awaitable
await vm.SetNameAsync("Alice");
await vm.SetAgeAsync(30);

Performance

ZeroAlloc.Notify provides async-first, fully awaitable handler dispatch — the only framework in this comparison where await vm.SetNameAsync(...) truly awaits all handlers. Refreshed benchmarks (.NET 10.0.7, i9-12900HK, BenchmarkDotNet v0.15.8, 5 attached handlers):

Honest framing: ZA.Notify is the slowest of the four and the only one that allocates — the 80 B is the ValueTask state machine for fan-out to async handlers. For pure-sync view models, Fody is the right choice (fastest, 0 B). ZA.Notify is the only library here that supports async handlers; the trade-off is the cost of that capability. At 124.7 ns / 80 B per setter, it still scales to ~8M property changes per second per thread.

See docs/performance.md for detailed benchmark results and zero-allocation design explanation.

Features

• Property Notifications — Strongly-typed, fully async PropertyChangedAsync events
• Collection Changes — CollectionChangedAsync with observable property support
• Data Validation — INotifyDataErrorInfoAsync for async error collection
• Sequential & Parallel — [InvokeSequentially] attribute for handler ordering
• Compiler Diagnostics — Missing handlers and misconfigurations caught at build time
• Async-First — Fully awaitable ValueTask handlers; no fire-and-forget, no callbacks
• Native AOT Compatible — No reflection at runtime; all dispatch resolved at compile time
• Source Generated — Full type safety with compile-time verification

Documentation

Examples

See the samples directory for complete working examples:

• WPF MVVM application
• ASP.NET Core data binding
• Console property notifications
• Collection change handling

License

MIT