RabstackQuery.Mvvm 0.3.0

RabStack Query MVVM

MVVM bindings for RabStack Query providing INotifyPropertyChanged ViewModels for MAUI, WPF, Avalonia, and other XAML frameworks. Built on CommunityToolkit.Mvvm source generators.

Installation

dotnet add package RabstackQuery.Mvvm

For Blazor apps, install RabstackQuery.Blazor instead, which includes this package and adds Blazor-specific component lifecycle management.

Quick Start

public partial class TodoListViewModel : ObservableObject, IDisposable
{
    public QueryViewModel<List<Todo>> TodosQuery { get; }
    public MutationViewModel<Todo, CreateTodoRequest> CreateTodo { get; }

    public TodoListViewModel(QueryClient client, ITodoApi api)
    {
        TodosQuery = client.UseQuery(
            ["todos"],
            async ctx => await api.GetTodosAsync(ctx.CancellationToken));

        CreateTodo = client.UseMutation<Todo, CreateTodoRequest>(
            async (request, _, ct) => await api.CreateTodoAsync(request, ct),
            new MutationCallbacks<Todo, CreateTodoRequest>
            {
                OnSuccess = (_, _, _) => client.InvalidateQueries(["todos"])
            });
    }

    public void Dispose()
    {
        TodosQuery.Dispose();
        CreateTodo.Dispose();
    }
}

XAML Binding

<StackLayout>
    <ActivityIndicator IsRunning="{Binding TodosQuery.IsLoading}"
                       IsVisible="{Binding TodosQuery.IsLoading}" />

    <Label Text="{Binding TodosQuery.Error.Message}"
           IsVisible="{Binding TodosQuery.IsError}" TextColor="Red" />

    <CollectionView ItemsSource="{Binding TodosQuery.Data}"
                    IsVisible="{Binding TodosQuery.IsSuccess}">
        <CollectionView.ItemTemplate>
            <DataTemplate>
                <Label Text="{Binding Title}" />
            </DataTemplate>
        </CollectionView.ItemTemplate>
    </CollectionView>

    <Button Text="Refresh" Command="{Binding TodosQuery.RefetchCommand}" />
    <Button Text="Add Todo" Command="{Binding CreateTodo.MutateCommand}" />
</StackLayout>

ViewModels

QueryViewModel<TData>

Wraps a QueryObserver with observable properties for data binding:

MutationViewModel<TData, TVariables>

Wraps a MutationObserver with observable properties and commands:

Call InvokeAsync(variables) for awaitable mutation execution with error propagation.

QueryCollectionViewModel<TItem>

Wraps a query whose data is a collection, exposing an ObservableCollection<TItem> for efficient list binding:

var todosCollection = client.UseQueryCollection(
    ["todos"],
    async ctx => await api.GetTodosAsync(ctx.CancellationToken),
    (data, items) =>
    {
        items.Clear();
        if (data is not null)
            foreach (var todo in data) items.Add(todo);
    });

// Bind to todosCollection.Items in XAML

Key Behaviors

• UI Thread Marshaling: All property changes are dispatched to SynchronizationContext.Current, captured at construction time
• Disposal Required: Always call Dispose() on ViewModels to unsubscribe from query observers and prevent memory leaks
• Command Error Handling: RefetchCommand and MutateCommand swallow exceptions by default for safe fire-and-forget binding. Use InvokeAsync when you need to handle errors

Documentation

See the GitHub repository for full documentation, architecture guide, and examples.

License

MIT