Feature Add Splat Registrations to IViewFor Generator (#289)

* Add Attribute Property

* Add Splat registration support to IViewFor generator

Introduces SplatRegistrationType to IViewFor attributes and source generator, enabling automatic registration of views for view models in Splat's service locator. Updates documentation, tests, and sample usage to demonstrate new registration options and extension method for bulk registration.

* Reduce the use of string builder

* Update IViewForGeneratorTests.FromIViewFor#ReactiveUI.ReactiveUISourceGeneratorsExtensions.g.verified.cs

Author: ChrisPulman

README.md

@@ -38,11 +38,23 @@ ReactiveUI Source Generators automatically generate ReactiveUI objects to stream
 - `[ReactiveCommand(OutputScheduler = nameof(_isheduler))]` using a Scheduler defined in the class
 - `[ReactiveCommand][property: AttributeToAddToCommand]` with Attribute passthrough
 - `[IViewFor(nameof(ViewModelName))]`
+- `[IViewFor<YourViewModelType>]`
+- `[IViewFor("YourNameSpace.YourGenericViewModel<int>")]` Generic
+- `[IViewFor<YourViewModelType>(RegistrationType = SplatRegistrationType.PerRequest)]` with Splat Registration Type for IViewFor registration.
+- `[IViewFor<YourViewModelType>(RegistrationType = SplatRegistrationType.LazySingleton)]` Generic with Splat Registration Type for IViewFor registration.
+- `[IViewFor<YourViewModelType>(RegistrationType = SplatRegistrationType.Constant)]` Generic with Splat Registration Type for IViewFor registration.
 - `[RoutedControlHost("YourNameSpace.CustomControl")]`
 - `[ViewModelControlHost("YourNameSpace.CustomControl")]`
 - `[BindableDerivedList]` Generates a derived list from a ReadOnlyObservableCollection backing field
 - `[ReactiveCollection]` Generates property changed notifications on add, remove, new actions on a ObservableCollection backing field
 
+#### IViewFor Registration generator
+
+To register all views for view models registered via the IViewFor Source Generator with a specified `RegistrationType`, call the following method during application startup:
+```csharp
+Splat.Locator.CurrentMutable.RegisterViewsForViewModelsSourceGenerated();
+```
+
 ### Compatibility Notes
 - For ReactiveUI versions **older than V19.5.31**, all `[ReactiveCommand]` options are supported except for async methods with a `CancellationToken`.
 - For **.NET Framework 4.8 and older**, add [Polyfill by Simon Cropp](https://github.com/SimonCropp/Polyfill) or [PolySharp by Sergio Pedri](https://github.com/Sergio0694/PolySharp) to your project and set the `LangVersion` to 12.0 or later in your project file.
@@ -63,11 +75,17 @@ Generates read-only properties backed by an `ObservableAsPropertyHelper` based o
 Generates commands, with options to add attributes or enable `CanExecute` functionality.
 
 ### `[IViewFor]`
-Links a view to a view model for data binding.
+Links a view to a view model for data binding. Supports generic types and Splat registration.
 
 ### `[RoutedControlHost]` and `[ViewModelControlHost]`
 Platform-specific attributes for control hosting in WinForms applications.
 
+### `[BindableDerivedList]`
+Generates a derived list from a `ReadOnlyObservableCollection` backing field.
+
+### `[ReactiveCollection]`
+Generates property changed notifications on add, remove, and new actions on an `ObservableCollection` backing field.
+
 ## Historical Approach
 
 ### Read-Write Properties
@@ -525,6 +543,35 @@ The class must inherit from a UI Control from any of the following platforms and
 - Avalonia (Avalonia)
 - Uno (Windows.UI.Xaml).
 
+### IViewFor with Splat Registration Type
+
+Choose from the following Splat Registration Types:
+- `SplatRegistrationType.PerRequest`
+- `SplatRegistrationType.LazySingleton`
+- `SplatRegistrationType.Constant`
+- `SplatRegistrationType.None` (Default if not specified - no registration is performed)
+
+```csharp
+using ReactiveUI.SourceGenerators;
+using Splat;
+[IViewFor<MyReactiveClass>(RegistrationType = SplatRegistrationType.PerRequest)]
+public partial class MyReactiveControl : UserControl
+{
+    public MyReactiveControl()
+    {
+        InitializeComponent();
+        ViewModel = Locator.Current.GetService<MyReactiveClass>();
+    }
+}
+```
+
+this will generate the following code to enable you register the marked Views as `IViewFor<ViewModel>` with Splat:
+```csharp
+using ReactiveUI.SourceGenerators;
+
+Splat.Locator.CurrentMutable.RegisterViewsForViewModelsSourceGenerated();
+```
+
 ### Usage IViewFor with ViewModel Name - Generic Types should be used with the fully qualified name, otherwise use nameof(ViewModelTypeName)
 ```csharp
 using ReactiveUI.SourceGenerators;

src/Directory.Packages.props

@@ -9,6 +9,7 @@
     <PackageVersion Include="Nerdbank.GitVersioning" Version="3.8.118" />
     <PackageVersion Include="NuGet.Common" Version="6.14.0" />
     <PackageVersion Include="NuGet.Protocol" Version="6.14.0" />
+    <PackageVersion Include="Splat" Version="16.0.1" />
     <PackageVersion Include="stylecop.analyzers" Version="1.2.0-beta.556" />
     <PackageVersion Include="Roslynator.Analyzers" Version="4.14.0" />
     <PackageVersion Include="ReactiveUI" Version="21.0.1" />
@@ -45,4 +46,4 @@
     <PackageVersion Include="Basic.Reference.Assemblies.Net80" Version="1.8.3" />
     <PackageVersion Include="Basic.Reference.Assemblies.Net80Windows" Version="1.8.3" />
   </ItemGroup>
-</Project>
+</Project>

src/ReactiveUI.SourceGenerator.Tests/IVIEWFOR/IViewForGeneratorTests.FromIViewFor#ReactiveUI.ReactiveUISourceGeneratorsExtensions.g.verified.cs

@@ -0,0 +1,23 @@
+//HintName: ReactiveUI.ReactiveUISourceGeneratorsExtensions.g.cs
+// <auto-generated/>
+#pragma warning disable
+#nullable enable
+
+using global::ReactiveUI;
+using global::Splat;
+
+namespace ReactiveUI.SourceGenerators
+{
+    /// <summary>
+    /// Source-generated registration extensions for ReactiveUI views.
+    /// </summary>
+    internal static class ReactiveUISourceGeneratorsExtensions
+    {
+        public static void RegisterViewsForViewModelsSourceGenerated(this global::Splat.IMutableDependencyResolver resolver)
+        {
+            if (resolver is null) throw new global::System.ArgumentNullException(nameof(resolver));
+        }
+    }
+}
+#nullable restore
+#pragma warning restore

src/ReactiveUI.SourceGenerator.Tests/IVIEWFOR/IViewForGeneratorTests.FromIViewFor#ReactiveUI.SourceGenerators.IViewForAttribute.g.verified.cs

@@ -18,7 +18,14 @@ namespace ReactiveUI.SourceGenerators;
 /// </remarks>
 /// <param name="viewModelType">Type of the view model.</param>
 [global::System.AttributeUsage(global::System.AttributeTargets.Class, AllowMultiple = false, Inherited = false)]
-internal sealed class IViewForAttribute<T> : global::System.Attribute;
+internal sealed class IViewForAttribute<T> : global::System.Attribute
+{
+    /// <summary>
+    /// Gets the Splat registration type for Splat registration.
+    /// Registers IViewFor<T> in the Splat service locator.
+    /// </summary>
+    public SplatRegistrationType RegistrationType { get; init; } = SplatRegistrationType.None;
+}
 
 /// <summary>
 /// IViewForAttribute.
@@ -27,8 +34,15 @@ internal sealed class IViewForAttribute<T> : global::System.Attribute;
 /// <remarks>
 /// Initializes a new instance of the <see cref="IViewForAttribute"/> class.
 /// </remarks>
-/// <param name="viewModelType">Type of the view model.</param>
+/// <param name="viewModelType">Type of the view model, ensure to use the full type name including namespace.</param>
 [global::System.AttributeUsage(global::System.AttributeTargets.Class, AllowMultiple = false, Inherited = false)]
-internal sealed class IViewForAttribute(string? viewModelType) : global::System.Attribute;
+internal sealed class IViewForAttribute(string? viewModelType) : global::System.Attribute
+{
+    /// <summary>
+    /// Gets the Splat registration type for Splat registration.
+    /// Registers IViewFor<T> in the Splat service locator.
+    /// </summary>
+    public SplatRegistrationType RegistrationType { get; init; } = SplatRegistrationType.None;
+}
 #nullable restore
 #pragma warning restore

src/ReactiveUI.SourceGenerator.Tests/REACTIVE/ReactiveGeneratorTests.FromReactivePartialProperties#ReactiveUI.SourceGenerators.AccessModifier.g.verified.cs

@@ -33,5 +33,13 @@ internal enum InheritanceModifier
     Override,
     New,
 }
+
+internal enum SplatRegistrationType
+{
+    None,
+    LazySingleton,
+    Constant,
+    PerRequest,
+}
 #nullable restore
 #pragma warning restore

src/ReactiveUI.SourceGenerator.Tests/REACTIVE/ReactiveGeneratorTests.FromReactiveProperiesWithAttributes#ReactiveUI.SourceGenerators.AccessModifier.g.verified.cs

@@ -33,5 +33,13 @@ internal enum InheritanceModifier
     Override,
     New,
 }
+
+internal enum SplatRegistrationType
+{
+    None,
+    LazySingleton,
+    Constant,
+    PerRequest,
+}
 #nullable restore
 #pragma warning restore

src/ReactiveUI.SourceGenerator.Tests/REACTIVE/ReactiveGeneratorTests.FromReactiveProperties#ReactiveUI.SourceGenerators.AccessModifier.g.verified.cs

@@ -33,5 +33,13 @@ internal enum InheritanceModifier
     Override,
     New,
 }
+
+internal enum SplatRegistrationType
+{
+    None,
+    LazySingleton,
+    Constant,
+    PerRequest,
+}
 #nullable restore
 #pragma warning restore

src/ReactiveUI.SourceGenerator.Tests/REACTIVE/ReactiveGeneratorTests.FromReactivePropertiesCalledValue#ReactiveUI.SourceGenerators.AccessModifier.g.verified.cs

@@ -33,5 +33,13 @@ internal enum InheritanceModifier
     Override,
     New,
 }
+
+internal enum SplatRegistrationType
+{
+    None,
+    LazySingleton,
+    Constant,
+    PerRequest,
+}
 #nullable restore
 #pragma warning restore

src/ReactiveUI.SourceGenerator.Tests/REACTIVE/ReactiveGeneratorTests.FromReactivePropertiesWithAccess#ReactiveUI.SourceGenerators.AccessModifier.g.verified.cs

@@ -33,5 +33,13 @@ internal enum InheritanceModifier
     Override,
     New,
 }
+
+internal enum SplatRegistrationType
+{
+    None,
+    LazySingleton,
+    Constant,
+    PerRequest,
+}
 #nullable restore
 #pragma warning restore

src/ReactiveUI.SourceGenerator.Tests/REACTIVE/ReactiveGeneratorTests.FromReactivePropertiesWithAttributesAccessAndInheritance#ReactiveUI.SourceGenerators.AccessModifier.g.verified.cs

@@ -33,5 +33,13 @@ internal enum InheritanceModifier
     Override,
     New,
 }
+
+internal enum SplatRegistrationType
+{
+    None,
+    LazySingleton,
+    Constant,
+    PerRequest,
+}
 #nullable restore
 #pragma warning restore