Feature Introduce ReactiveUIBuilder

src/ReactiveUI.Blazor/ReactiveUIBuilderBlazorExtensions.cs

@@ -0,0 +1,27 @@
+// Copyright (c) 2025 .NET Foundation and Contributors. All rights reserved.
+// Licensed to the .NET Foundation under one or more agreements.
+// The .NET Foundation licenses this file to you under the MIT license.
+// See the LICENSE file in the project root for full license information.
+
+namespace ReactiveUI.Blazor;
+
+/// <summary>
+/// Blazor-specific extensions for ReactiveUIBuilder.
+/// </summary>
+public static class ReactiveUIBuilderBlazorExtensions
+{
+    /// <summary>
+    /// Registers Blazor-specific services.
+    /// </summary>
+    /// <param name="builder">The builder instance.</param>
+    /// <returns>The builder instance for method chaining.</returns>
+    public static Builder.ReactiveUIBuilder WithBlazor(this Builder.ReactiveUIBuilder builder)
+    {
+        if (builder is null)
+        {
+            throw new ArgumentNullException(nameof(builder));
+        }
+
+        return builder.WithPlatformModule<Registrations>();
+    }
+}

src/ReactiveUI.Drawing/ReactiveUIBuilderDrawingExtensions.cs

@@ -0,0 +1,27 @@
+// Copyright (c) 2025 .NET Foundation and Contributors. All rights reserved.
+// Licensed to the .NET Foundation under one or more agreements.
+// The .NET Foundation licenses this file to you under the MIT license.
+// See the LICENSE file in the project root for full license information.
+
+namespace ReactiveUI.Drawing;
+
+/// <summary>
+/// Drawing-specific extensions for ReactiveUIBuilder.
+/// </summary>
+public static class ReactiveUIBuilderDrawingExtensions
+{
+    /// <summary>
+    /// Registers Drawing-specific services.
+    /// </summary>
+    /// <param name="builder">The builder instance.</param>
+    /// <returns>The builder instance for method chaining.</returns>
+    public static Builder.ReactiveUIBuilder WithDrawing(this Builder.ReactiveUIBuilder builder)
+    {
+        if (builder is null)
+        {
+            throw new ArgumentNullException(nameof(builder));
+        }
+
+        return builder.WithPlatformModule<Registrations>();
+    }
+}

src/ReactiveUI.Maui/ReactiveUIBuilderMauiExtensions.cs

@@ -0,0 +1,27 @@
+// Copyright (c) 2025 .NET Foundation and Contributors. All rights reserved.
+// Licensed to the .NET Foundation under one or more agreements.
+// The .NET Foundation licenses this file to you under the MIT license.
+// See the LICENSE file in the project root for full license information.
+
+namespace ReactiveUI.Maui;
+
+/// <summary>
+/// MAUI-specific extensions for ReactiveUIBuilder.
+/// </summary>
+public static class ReactiveUIBuilderMauiExtensions
+{
+    /// <summary>
+    /// Registers MAUI-specific services.
+    /// </summary>
+    /// <param name="builder">The builder instance.</param>
+    /// <returns>The builder instance for method chaining.</returns>
+    public static Builder.ReactiveUIBuilder WithMaui(this Builder.ReactiveUIBuilder builder)
+    {
+        if (builder is null)
+        {
+            throw new ArgumentNullException(nameof(builder));
+        }
+
+        return builder.WithPlatformModule<Registrations>();
+    }
+}

src/ReactiveUI.Tests/API/ApiApprovalTests.ReactiveUI.DotNet8_0.verified.txt

@@ -909,6 +909,10 @@ namespace ReactiveUI
         public System.IDisposable DelayChangeNotifications() { }
         public System.IDisposable SuppressChangeNotifications() { }
     }
+    public static class ReactiveUIBuilderExtensions
+    {
+        public static ReactiveUI.Builder.ReactiveUIBuilder CreateBuilder(this Splat.IMutableDependencyResolver resolver) { }
+    }
     [System.Diagnostics.CodeAnalysis.RequiresDynamicCode("The method uses reflection and will not work in AOT environments.")]
     [System.Diagnostics.CodeAnalysis.RequiresUnreferencedCode("The method uses reflection and will not work in AOT environments.")]
     public static class Reflection
@@ -1255,3 +1259,28 @@ namespace ReactiveUI
             where TSender :  class { }
     }
 }
+namespace ReactiveUI.Builder
+{
+    public interface IReactiveUIModule
+    {
+        void Configure(Splat.IMutableDependencyResolver resolver);
+    }
+    public sealed class ReactiveUIBuilder
+    {
+        public ReactiveUIBuilder(Splat.IMutableDependencyResolver resolver) { }
+        [System.Diagnostics.CodeAnalysis.RequiresDynamicCode("The method uses reflection and will not work in AOT environments.")]
+        [System.Diagnostics.CodeAnalysis.RequiresUnreferencedCode("The method uses reflection and will not work in AOT environments.")]
+        public void Build() { }
+        [System.Diagnostics.CodeAnalysis.RequiresDynamicCode("The method uses reflection and will not work in AOT environments.")]
+        [System.Diagnostics.CodeAnalysis.RequiresUnreferencedCode("The method uses reflection and will not work in AOT environments.")]
+        public ReactiveUI.Builder.ReactiveUIBuilder WithCoreServices() { }
+        public ReactiveUI.Builder.ReactiveUIBuilder WithCustomRegistration(System.Action<Splat.IMutableDependencyResolver> configureAction) { }
+        public ReactiveUI.Builder.ReactiveUIBuilder WithModule(ReactiveUI.Builder.IReactiveUIModule registrationModule) { }
+        [System.Diagnostics.CodeAnalysis.RequiresDynamicCode("The method uses reflection and will not work in AOT environments.")]
+        [System.Diagnostics.CodeAnalysis.RequiresUnreferencedCode("The method uses reflection and will not work in AOT environments.")]
+        public ReactiveUI.Builder.ReactiveUIBuilder WithPlatformServices() { }
+        [System.Diagnostics.CodeAnalysis.RequiresDynamicCode("The method uses reflection and will not work in AOT environments.")]
+        [System.Diagnostics.CodeAnalysis.RequiresUnreferencedCode("The method uses reflection and will not work in AOT environments.")]
+        public ReactiveUI.Builder.ReactiveUIBuilder WithViewsFromAssembly(System.Reflection.Assembly assembly) { }
+    }
+}

src/ReactiveUI.Tests/API/ApiApprovalTests.ReactiveUI.DotNet9_0.verified.txt

@@ -909,6 +909,10 @@ namespace ReactiveUI
         public System.IDisposable DelayChangeNotifications() { }
         public System.IDisposable SuppressChangeNotifications() { }
     }
+    public static class ReactiveUIBuilderExtensions
+    {
+        public static ReactiveUI.Builder.ReactiveUIBuilder CreateBuilder(this Splat.IMutableDependencyResolver resolver) { }
+    }
     [System.Diagnostics.CodeAnalysis.RequiresDynamicCode("The method uses reflection and will not work in AOT environments.")]
     [System.Diagnostics.CodeAnalysis.RequiresUnreferencedCode("The method uses reflection and will not work in AOT environments.")]
     public static class Reflection
@@ -1255,3 +1259,28 @@ namespace ReactiveUI
             where TSender :  class { }
     }
 }
+namespace ReactiveUI.Builder
+{
+    public interface IReactiveUIModule
+    {
+        void Configure(Splat.IMutableDependencyResolver resolver);
+    }
+    public sealed class ReactiveUIBuilder
+    {
+        public ReactiveUIBuilder(Splat.IMutableDependencyResolver resolver) { }
+        [System.Diagnostics.CodeAnalysis.RequiresDynamicCode("The method uses reflection and will not work in AOT environments.")]
+        [System.Diagnostics.CodeAnalysis.RequiresUnreferencedCode("The method uses reflection and will not work in AOT environments.")]
+        public void Build() { }
+        [System.Diagnostics.CodeAnalysis.RequiresDynamicCode("The method uses reflection and will not work in AOT environments.")]
+        [System.Diagnostics.CodeAnalysis.RequiresUnreferencedCode("The method uses reflection and will not work in AOT environments.")]
+        public ReactiveUI.Builder.ReactiveUIBuilder WithCoreServices() { }
+        public ReactiveUI.Builder.ReactiveUIBuilder WithCustomRegistration(System.Action<Splat.IMutableDependencyResolver> configureAction) { }
+        public ReactiveUI.Builder.ReactiveUIBuilder WithModule(ReactiveUI.Builder.IReactiveUIModule registrationModule) { }
+        [System.Diagnostics.CodeAnalysis.RequiresDynamicCode("The method uses reflection and will not work in AOT environments.")]
+        [System.Diagnostics.CodeAnalysis.RequiresUnreferencedCode("The method uses reflection and will not work in AOT environments.")]
+        public ReactiveUI.Builder.ReactiveUIBuilder WithPlatformServices() { }
+        [System.Diagnostics.CodeAnalysis.RequiresDynamicCode("The method uses reflection and will not work in AOT environments.")]
+        [System.Diagnostics.CodeAnalysis.RequiresUnreferencedCode("The method uses reflection and will not work in AOT environments.")]
+        public ReactiveUI.Builder.ReactiveUIBuilder WithViewsFromAssembly(System.Reflection.Assembly assembly) { }
+    }
+}

src/ReactiveUI.Tests/API/ApiApprovalTests.ReactiveUI.Net4_7.verified.txt

@@ -817,6 +817,10 @@ namespace ReactiveUI
         public System.IDisposable DelayChangeNotifications() { }
         public System.IDisposable SuppressChangeNotifications() { }
     }
+    public static class ReactiveUIBuilderExtensions
+    {
+        public static ReactiveUI.Builder.ReactiveUIBuilder CreateBuilder(this Splat.IMutableDependencyResolver resolver) { }
+    }
     public static class Reflection
     {
         public static string ExpressionToPropertyNames(System.Linq.Expressions.Expression? expression) { }
@@ -1148,3 +1152,20 @@ namespace ReactiveUI
             where TSender :  class { }
     }
 }
+namespace ReactiveUI.Builder
+{
+    public interface IReactiveUIModule
+    {
+        void Configure(Splat.IMutableDependencyResolver resolver);
+    }
+    public sealed class ReactiveUIBuilder
+    {
+        public ReactiveUIBuilder(Splat.IMutableDependencyResolver resolver) { }
+        public void Build() { }
+        public ReactiveUI.Builder.ReactiveUIBuilder WithCoreServices() { }
+        public ReactiveUI.Builder.ReactiveUIBuilder WithCustomRegistration(System.Action<Splat.IMutableDependencyResolver> configureAction) { }
+        public ReactiveUI.Builder.ReactiveUIBuilder WithModule(ReactiveUI.Builder.IReactiveUIModule registrationModule) { }
+        public ReactiveUI.Builder.ReactiveUIBuilder WithPlatformServices() { }
+        public ReactiveUI.Builder.ReactiveUIBuilder WithViewsFromAssembly(System.Reflection.Assembly assembly) { }
+    }
+}

src/ReactiveUI.Tests/Platforms/winforms/API/WinformsApiApprovalTests.Winforms.DotNet8_0.verified.txt

@@ -32,6 +32,10 @@ namespace ReactiveUI.Winforms
         public PlatformOperations() { }
         public string? GetOrientation() { }
     }
+    public static class ReactiveUIBuilderWinFormsExtensions
+    {
+        public static ReactiveUI.Builder.ReactiveUIBuilder WithWinForms(this ReactiveUI.Builder.ReactiveUIBuilder builder) { }
+    }
     public class ReactiveUserControlNonGeneric : System.Windows.Forms.UserControl, ReactiveUI.IActivatableView, ReactiveUI.IViewFor
     {
         public ReactiveUserControlNonGeneric() { }

src/ReactiveUI.Tests/Platforms/winforms/API/WinformsApiApprovalTests.Winforms.DotNet9_0.verified.txt

@@ -32,6 +32,10 @@ namespace ReactiveUI.Winforms
         public PlatformOperations() { }
         public string? GetOrientation() { }
     }
+    public static class ReactiveUIBuilderWinFormsExtensions
+    {
+        public static ReactiveUI.Builder.ReactiveUIBuilder WithWinForms(this ReactiveUI.Builder.ReactiveUIBuilder builder) { }
+    }
     public class ReactiveUserControlNonGeneric : System.Windows.Forms.UserControl, ReactiveUI.IActivatableView, ReactiveUI.IViewFor
     {
         public ReactiveUserControlNonGeneric() { }

src/ReactiveUI.Tests/Platforms/winforms/API/WinformsApiApprovalTests.Winforms.Net4_7.verified.txt

@@ -30,6 +30,10 @@ namespace ReactiveUI.Winforms
         public PlatformOperations() { }
         public string? GetOrientation() { }
     }
+    public static class ReactiveUIBuilderWinFormsExtensions
+    {
+        public static ReactiveUI.Builder.ReactiveUIBuilder WithWinForms(this ReactiveUI.Builder.ReactiveUIBuilder builder) { }
+    }
     public class ReactiveUserControlNonGeneric : System.Windows.Forms.UserControl, ReactiveUI.IActivatableView, ReactiveUI.IViewFor
     {
         public ReactiveUserControlNonGeneric() { }

src/ReactiveUI.Tests/Platforms/winforms/ReactiveUIBuilderWinFormsTests.cs

@@ -0,0 +1,58 @@
+// Copyright (c) 2025 .NET Foundation and Contributors. All rights reserved.
+// Licensed to the .NET Foundation under one or more agreements.
+// The .NET Foundation licenses this file to you under the MIT license.
+// See the LICENSE file in the project root for full license information.
+
+using ReactiveUI.Winforms;
+
+namespace ReactiveUI.Tests.Platforms.Winforms;
+
+/// <summary>
+/// Tests for WinForms-specific ReactiveUIBuilder functionality.
+/// </summary>
+public class ReactiveUIBuilderWinFormsTests
+{
+    /// <summary>
+    /// Test that WinForms services can be registered using the builder.
+    /// </summary>
+    [Fact]
+    public void WithWinForms_Should_Register_WinForms_Services()
+    {
+        // Arrange
+        using var locator = new ModernDependencyResolver();
+        var builder = locator.CreateBuilder();
+
+        // Act
+        builder.WithWinForms().Build();
+
+        // Assert
+        var platformOperations = locator.GetService<IPlatformOperations>();
+        Assert.NotNull(platformOperations);
+
+        var activationFetcher = locator.GetService<IActivationForViewFetcher>();
+        Assert.NotNull(activationFetcher);
+    }
+
+    /// <summary>
+    /// Test that the builder can chain WinForms registration with core services.
+    /// </summary>
+    [Fact]
+    public void WithCoreServices_AndWinForms_Should_Register_All_Services()
+    {
+        // Arrange
+        using var locator = new ModernDependencyResolver();
+        var builder = locator.CreateBuilder();
+
+        // Act
+        builder.WithCoreServices().WithWinForms().Build();
+
+        // Assert
+        // Core services
+        var observableProperty = locator.GetService<ICreatesObservableForProperty>();
+        Assert.NotNull(observableProperty);
+
+        // WinForms-specific services
+        var platformOperations = locator.GetService<IPlatformOperations>();
+        Assert.NotNull(platformOperations);
+    }
+}

src/ReactiveUI.Tests/Platforms/wpf/API/WpfApiApprovalTests.Wpf.DotNet8_0.verified.txt

@@ -140,6 +140,10 @@ namespace ReactiveUI
 }
 namespace ReactiveUI.Wpf
 {
+    public static class ReactiveUIBuilderWpfExtensions
+    {
+        public static ReactiveUI.Builder.ReactiveUIBuilder WithWpf(this ReactiveUI.Builder.ReactiveUIBuilder builder) { }
+    }
     public class Registrations
     {
         public Registrations() { }

src/ReactiveUI.Tests/Platforms/wpf/API/WpfApiApprovalTests.Wpf.DotNet9_0.verified.txt

@@ -140,6 +140,10 @@ namespace ReactiveUI
 }
 namespace ReactiveUI.Wpf
 {
+    public static class ReactiveUIBuilderWpfExtensions
+    {
+        public static ReactiveUI.Builder.ReactiveUIBuilder WithWpf(this ReactiveUI.Builder.ReactiveUIBuilder builder) { }
+    }
     public class Registrations
     {
         public Registrations() { }

src/ReactiveUI.Tests/Platforms/wpf/API/WpfApiApprovalTests.Wpf.Net4_7.verified.txt

@@ -138,6 +138,10 @@ namespace ReactiveUI
 }
 namespace ReactiveUI.Wpf
 {
+    public static class ReactiveUIBuilderWpfExtensions
+    {
+        public static ReactiveUI.Builder.ReactiveUIBuilder WithWpf(this ReactiveUI.Builder.ReactiveUIBuilder builder) { }
+    }
     public class Registrations
     {
         public Registrations() { }

src/ReactiveUI.Tests/Platforms/wpf/ReactiveUIBuilderWpfTests.cs

@@ -0,0 +1,58 @@
+// Copyright (c) 2025 .NET Foundation and Contributors. All rights reserved.
+// Licensed to the .NET Foundation under one or more agreements.
+// The .NET Foundation licenses this file to you under the MIT license.
+// See the LICENSE file in the project root for full license information.
+
+using ReactiveUI.Wpf;
+
+namespace ReactiveUI.Tests.Platforms.Wpf;
+
+/// <summary>
+/// Tests for WPF-specific ReactiveUIBuilder functionality.
+/// </summary>
+public class ReactiveUIBuilderWpfTests
+{
+    /// <summary>
+    /// Test that WPF services can be registered using the builder.
+    /// </summary>
+    [Fact]
+    public void WithWpf_Should_Register_Wpf_Services()
+    {
+        // Arrange
+        using var locator = new ModernDependencyResolver();
+        var builder = locator.CreateBuilder();
+
+        // Act
+        builder.WithWpf().Build();
+
+        // Assert
+        var platformOperations = locator.GetService<IPlatformOperations>();
+        Assert.NotNull(platformOperations);
+
+        var activationFetcher = locator.GetService<IActivationForViewFetcher>();
+        Assert.NotNull(activationFetcher);
+    }
+
+    /// <summary>
+    /// Test that the builder can chain WPF registration with core services.
+    /// </summary>
+    [Fact]
+    public void WithCoreServices_AndWpf_Should_Register_All_Services()
+    {
+        // Arrange
+        using var locator = new ModernDependencyResolver();
+        var builder = locator.CreateBuilder();
+
+        // Act
+        builder.WithCoreServices().WithWpf().Build();
+
+        // Assert
+        // Core services
+        var observableProperty = locator.GetService<ICreatesObservableForProperty>();
+        Assert.NotNull(observableProperty);
+
+        // WPF-specific services
+        var platformOperations = locator.GetService<IPlatformOperations>();
+        Assert.NotNull(platformOperations);
+    }
+}