Fix Wrong UWP Scheduler

Fix for #2993

Author: ChrisPulman

src/Directory.build.props

@@ -50,7 +50,7 @@
     <PackageReference Include="Microsoft.Reactive.Testing" Version="5.0.0" />
     <PackageReference Include="PublicApiGenerator" Version="10.2.0" />
     <PackageReference Include="coverlet.msbuild" Version="3.1.0" PrivateAssets="All" />
-    <PackageReference Include="Verify.Xunit" Version="14.0.1" />
+    <PackageReference Include="Verify.Xunit" Version="14.1.1" />
   </ItemGroup>
 
   <ItemGroup Condition="'$(IsTestProject)' != 'true'">

src/ReactiveUI.Tests/Platforms/windows-xaml/Api/XamlApiApprovalTests.Blend.Net4_8.received.txt

@@ -25,7 +25,7 @@ public class ActivationForViewFetcher : IActivationForViewFetcher
     /// <inheritdoc/>
     public IObservable<bool> GetActivationForView(IActivatableView view)
     {
-        if (!(view is FrameworkElement fe))
+        if (view is not FrameworkElement fe)
         {
             return Observable<bool>.Empty;
         }
@@ -54,4 +54,4 @@ public IObservable<bool> GetActivationForView(IActivatableView view)
                .Switch()
                .DistinctUntilChanged();
     }
-}
+}

src/ReactiveUI.Tests/Platforms/winforms/API/WinformsApiApprovalTests.Winforms.DotNet5_0.received.txt

@@ -74,7 +74,7 @@ public bool ExecuteHook(object? source, object target, Func<IObservedChange<obje
             var viewProperties = getCurrentViewProperties();
             var lastViewProperty = viewProperties.LastOrDefault();
 
-            if (!(lastViewProperty?.Sender is ItemsControl itemsControl))
+            if (lastViewProperty?.Sender is not ItemsControl itemsControl)
             {
                 return true;
             }

src/ReactiveUI.Uwp/ActivationForViewFetcher.cs

@@ -31,5 +31,11 @@ public void Register(Action<Func<object>, Type> registerFunction)
         registerFunction(() => new AutoDataTemplateBindingHook(), typeof(IPropertyBindingHook));
 
         registerFunction(() => new WinRTAppDataDriver(), typeof(ISuspensionDriver));
+
+        if (!ModeDetector.InUnitTestRunner())
+        {
+            RxApp.TaskpoolScheduler = TaskPoolScheduler.Default;
+            RxApp.MainThreadScheduler = new SingleWindowDispatcherScheduler();
+        }
     }
-}
+}

src/ReactiveUI.Uwp/Common/AutoDataTemplateBindingHook.cs

@@ -13,9 +13,6 @@ namespace System.Reactive.Concurrency
     /// <summary>
     /// Represents an object that schedules units of work on a <see cref="Microsoft.UI.Dispatching.DispatcherQueue"/>.
     /// </summary>
-    /// <remarks>
-    /// This scheduler type is typically used indirectly through the <see cref="Linq.DispatcherObservable.ObserveOnDispatcher{TSource}(IObservable{TSource})"/> and <see cref="Linq.DispatcherObservable.SubscribeOnDispatcher{TSource}(IObservable{TSource})"/> methods that use the Dispatcher on the calling thread.
-    /// </remarks>
     public class DispatcherQueueScheduler : LocalScheduler, ISchedulerPeriodic
     {
         /// <summary>
@@ -47,7 +44,7 @@ public DispatcherQueueScheduler(DispatcherQueue dispatcherQueue)
         }
 
         /// <summary>
-        /// Constructs a <see cref="DispatcherScheduler"/> that schedules units of work on the given <see cref="Microsoft.UI.Dispatching.DispatcherQueue"/> at the given priority.
+        /// Constructs a DispatcherScheduler that schedules units of work on the given <see cref="Microsoft.UI.Dispatching.DispatcherQueue"/> at the given priority.
         /// </summary>
         /// <param name="dispatcherQueue"><see cref="Microsoft.UI.Dispatching.DispatcherQueue"/> to schedule work on.</param>
         /// <param name="priority">Priority at which units of work are scheduled.</param>

src/ReactiveUI.Uwp/PlatformRegistrations.cs

@@ -0,0 +1,87 @@
+// Copyright (c) 2021 .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.
+// <auto-generated />
+
+using System;
+using System.ComponentModel;
+using Splat;
+
+#nullable enable
+namespace ReactiveUI;
+
+/// <summary>
+/// Binding Type Converter for component model.
+/// </summary>
+public class ComponentModelTypeConverter : IBindingTypeConverter
+{
+    private readonly MemoizingMRUCache<(Type fromType, Type toType), TypeConverter?> _typeConverterCache = new (
+     (types, _) =>
+     {
+         // NB: String is a Magical Type(tm) to TypeConverters. If we are
+         // converting from string => int, we need the Int converter, not
+         // the string converter :-/
+         if (types.fromType == typeof(string))
+         {
+             types = (types.toType, types.fromType);
+         }
+
+         var converter = TypeDescriptor.GetConverter(types.fromType);
+         return converter.CanConvertTo(types.toType) ? converter : null;
+     }, RxApp.SmallCacheLimit);
+
+    /// <inheritdoc/>
+    public int GetAffinityForObjects(Type fromType, Type toType)
+    {
+        var converter = _typeConverterCache.Get((fromType, toType));
+        return converter is not null ? 10 : 0;
+    }
+
+    /// <inheritdoc/>
+    public bool TryConvert(object? from, Type toType, object? conversionHint, out object? result)
+    {
+        if (from is null)
+        {
+            result = null;
+            return true;
+        }
+
+        var fromType = from.GetType();
+        var converter = _typeConverterCache.Get((fromType, toType));
+
+        if (converter is null)
+        {
+            throw new ArgumentException($"Can't convert {fromType} to {toType}. To fix this, register a IBindingTypeConverter");
+        }
+
+        try
+        {
+            // TODO: This should use conversionHint to determine whether this is locale-aware or not
+            result = (fromType == typeof(string)) ?
+                         converter.ConvertFrom(from) : converter.ConvertTo(from, toType);
+
+            return true;
+        }
+        catch (FormatException)
+        {
+            result = null;
+            return false;
+        }
+        catch (Exception e)
+        {
+            // Errors from ConvertFrom end up here but wrapped in
+            // outer exception. Add more types here as required.
+            // IndexOutOfRangeException is given when trying to
+            // convert empty strings with some/all? converters
+            if (e.InnerException is IndexOutOfRangeException ||
+                e.InnerException is FormatException)
+            {
+                result = null;
+                return false;
+            }
+
+            throw new Exception($"Can't convert from {@from.GetType()} to {toType}.", e);
+        }
+    }
+}

src/ReactiveUI.Uwp/Registrations.cs

@@ -0,0 +1,28 @@
+// Copyright (c) 2021 .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.
+// <auto-generated />
+
+using System;
+using System.Reactive.Concurrency;
+using Splat;
+
+namespace ReactiveUI;
+
+/// <summary>
+/// .NET Framework platform registrations.
+/// </summary>
+/// <seealso cref="ReactiveUI.IWantsToRegisterStuff" />
+public class PlatformRegistrations : IWantsToRegisterStuff
+{
+    /// <inheritdoc/>
+    public void Register(Action<Func<object>, Type> registerFunction)
+    {
+        if (registerFunction is null)
+        {
+            throw new ArgumentNullException(nameof(registerFunction));
+        }
+        // Registration is done in Registrations of ReactiveUI.Uap
+    }
+}