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michaelstonismichaelstonis
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Merge pull request #37 from TheEightBot/feature/reactiveui-24-and-windows-platforms
Fix Uno/Avalonia WhenAnyValue going silent after first value; bump Uno.WinUI to 6.6.184
2 parents d4f3d97 + 6b75ff3 commit 31bc7cf

5 files changed

Lines changed: 186 additions & 4 deletions

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‎Directory.Packages.props‎

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Original file line numberDiff line numberDiff line change
@@ -74,7 +74,7 @@
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Stellar.Avalonia does. -->
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<ItemGroup>
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<PackageVersion Include="Microsoft.WindowsAppSDK" Version="2.3.1" />
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<PackageVersion Include="Uno.WinUI" Version="6.6.176" />
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<PackageVersion Include="Uno.WinUI" Version="6.6.184" />
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</ItemGroup>
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<!-- Source generators. Roslyn is pinned to 5.0.0 rather than the newest

‎Stellar.Avalonia/AvaloniaObjectObservableForProperty.cs‎

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using System.Linq.Expressions;
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using System.Reactive.Disposables;
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using System.Reactive.Linq;
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using Avalonia;
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using ReactiveUI;
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namespace Stellar.Avalonia;
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/// <summary>
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/// Creates change notifications for <see cref="AvaloniaProperty"/>-backed properties on
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/// <see cref="AvaloniaObject"/>s (windows, controls) so that <c>WhenAnyValue</c> chains and
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/// bindings rooted at a view keep emitting after the initial value. Replaces
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/// Avalonia.ReactiveUI's AvaloniaObjectObservableForProperty, which has no ReactiveUI
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/// 24-compatible release. Without it, resolution falls back to
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/// <c>POCOObservableForProperty</c> (AvaloniaObject does not implement
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/// INotifyPropertyChanged), which only ever produces the current value.
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/// </summary>
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public sealed class AvaloniaObjectObservableForProperty : ICreatesObservableForProperty
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{
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public int GetAffinityForObject(Type type, string propertyName) =>
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GetAffinityForObject(type, propertyName, beforeChanged: false);
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// 4 matches ReactiveUI's own platform property handlers: above the POCO fallback,
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// below the IReactiveObject and INPC handlers. Only claims properties actually
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// registered with Avalonia's property system; plain CLR properties resolve elsewhere.
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// The PropertyChanged event only reports values after they change, so beforeChanged
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// requests are declined and resolve elsewhere.
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public int GetAffinityForObject(Type type, string propertyName, bool beforeChanged) =>
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!beforeChanged &&
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typeof(AvaloniaObject).IsAssignableFrom(type) &&
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AvaloniaPropertyRegistry.Instance.FindRegistered(type, propertyName) is not null
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? 4
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: 0;
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public IObservable<IObservedChange<object?, object?>> GetNotificationForProperty(object sender, Expression expression, string propertyName) =>
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GetNotificationForProperty(sender, expression, propertyName, beforeChanged: false, suppressWarnings: false);
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public IObservable<IObservedChange<object?, object?>> GetNotificationForProperty(object sender, Expression expression, string propertyName, bool beforeChanged) =>
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GetNotificationForProperty(sender, expression, propertyName, beforeChanged, suppressWarnings: false);
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public IObservable<IObservedChange<object?, object?>> GetNotificationForProperty(object sender, Expression expression, string propertyName, bool beforeChanged, bool suppressWarnings)
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{
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if (beforeChanged)
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{
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return Observable.Never<IObservedChange<object?, object?>>();
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}
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if (sender is not AvaloniaObject avaloniaObject)
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{
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throw new ArgumentException($"Sender must be an AvaloniaObject, but was {sender?.GetType().FullName ?? \"null\"}.", nameof(sender));
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}
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var property = AvaloniaPropertyRegistry.Instance.FindRegistered(sender.GetType(), propertyName);
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if (property is null)
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{
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if (suppressWarnings)
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{
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return Observable.Never<IObservedChange<object?, object?>>();
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}
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throw new ArgumentException($"No AvaloniaProperty named '{propertyName}' is registered on {sender.GetType().FullName}.", nameof(propertyName));
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}
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return Observable.Create<IObservedChange<object?, object?>>(
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observer =>
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{
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void Handler(object? _, AvaloniaPropertyChangedEventArgs args)
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if (args.Property == property)
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{
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observer.OnNext(new ObservedChange<object?, object?>(sender, expression, default));
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}
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}
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avaloniaObject.PropertyChanged += Handler;
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return Disposable.Create(() => avaloniaObject.PropertyChanged -= Handler);
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});
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}
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}

‎Stellar.Avalonia/Extensions/AppBuilderExtensions.cs‎

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Original file line numberDiff line numberDiff line change
@@ -23,7 +23,11 @@ public static AppBuilder UseStellarComponents(this AppBuilder appBuilder)
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RxAppBuilder
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.CreateReactiveUIBuilder()
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.WithRegistration(
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static resolver => resolver.RegisterConstant<IActivationForViewFetcher>(new AvaloniaActivationForViewFetcher()))
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static resolver =>
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{
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resolver.RegisterConstant<IActivationForViewFetcher>(new AvaloniaActivationForViewFetcher());
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resolver.RegisterConstant<ICreatesObservableForProperty>(new AvaloniaObjectObservableForProperty());
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})
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.WithMainThreadScheduler(AvaloniaScheduler.Instance)
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.WithTaskPoolScheduler(Schedulers.ShortTermThreadPoolScheduler)
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.Build();

‎Stellar.Uno/DependencyObjectObservableForProperty.cs‎

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@@ -0,0 +1,94 @@
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using System.Linq.Expressions;
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using System.Reflection;
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using Microsoft.UI.Xaml;
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namespace Stellar.Uno;
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/// <summary>
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/// Creates change notifications for <see cref="DependencyProperty"/>-backed properties on
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/// <see cref="DependencyObject"/>s (pages, controls) so that <c>WhenAnyValue</c> chains and
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/// bindings rooted at a view keep emitting after the initial value. ReactiveUI's own
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/// implementation of this lives in its WinUI/Uno platform packages, none of which have a
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/// ReactiveUI 24-compatible Uno release, so Stellar registers this one. Without it,
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/// resolution falls back to <c>POCOObservableForProperty</c>, which only ever produces the
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/// current value.
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/// </summary>
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public sealed class DependencyObjectObservableForProperty : ICreatesObservableForProperty
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{
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public int GetAffinityForObject(Type type, string propertyName) =>
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GetAffinityForObject(type, propertyName, beforeChanged: false);
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// 4 matches ReactiveUI's own DependencyObject handlers: above the POCO fallback,
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// below the IReactiveObject and INPC handlers, which serve those objects better.
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// DependencyProperty callbacks cannot observe values before they change, so
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// beforeChanged requests are declined and resolve elsewhere.
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public int GetAffinityForObject(Type type, string propertyName, bool beforeChanged)
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{
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if (beforeChanged || !typeof(DependencyObject).IsAssignableFrom(type))
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{
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return 0;
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}
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return GetDependencyProperty(type, propertyName) is null ? 0 : 4;
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}
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35+
public IObservable<IObservedChange<object?, object?>> GetNotificationForProperty(object sender, Expression expression, string propertyName) =>
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GetNotificationForProperty(sender, expression, propertyName, beforeChanged: false, suppressWarnings: false);
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38+
public IObservable<IObservedChange<object?, object?>> GetNotificationForProperty(object sender, Expression expression, string propertyName, bool beforeChanged) =>
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GetNotificationForProperty(sender, expression, propertyName, beforeChanged, suppressWarnings: false);
40+
41+
public IObservable<IObservedChange<object?, object?>> GetNotificationForProperty(object sender, Expression expression, string propertyName, bool beforeChanged, bool suppressWarnings)
42+
{
43+
if (beforeChanged)
44+
{
45+
return Observable.Never<IObservedChange<object?, object?>>();
46+
}
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48+
if (sender is not DependencyObject dependencyObject)
49+
{
50+
throw new ArgumentException($"Sender must be a DependencyObject, but was {sender?.GetType().FullName ?? \"null\"}.", nameof(sender));
51+
}
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var dependencyProperty = GetDependencyProperty(sender.GetType(), propertyName);
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55+
if (dependencyProperty is null)
56+
{
57+
if (suppressWarnings)
58+
{
59+
return Observable.Never<IObservedChange<object?, object?>>();
60+
}
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62+
throw new ArgumentException($"No DependencyProperty named '{propertyName}Property' was found on {sender.GetType().FullName}.", nameof(propertyName));
63+
}
64+
return Observable.Create<IObservedChange<object?, object?>>(
65+
observer =>
66+
{
67+
var token = dependencyObject.RegisterPropertyChangedCallback(
68+
dependencyProperty,
69+
(_, _) => observer.OnNext(new ObservedChange<object?, object?>(sender, expression, default)));
70+
71+
return Disposable.Create(() => dependencyObject.UnregisterPropertyChangedCallback(dependencyProperty, token));
72+
});
73+
}
74+
75+
private static DependencyProperty? GetDependencyProperty(Type type, string propertyName)
76+
{
77+
var memberName = propertyName + "Property";
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79+
for (var current = type; current is not null; current = current.BaseType)
80+
{
81+
if (current.GetProperty(memberName, BindingFlags.Public | BindingFlags.Static | BindingFlags.DeclaredOnly)?.GetValue(null) is DependencyProperty fromProperty)
82+
{
83+
return fromProperty;
84+
}
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86+
if (current.GetField(memberName, BindingFlags.Public | BindingFlags.Static | BindingFlags.DeclaredOnly)?.GetValue(null) is DependencyProperty fromField)
87+
{
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return fromField;
89+
}
90+
}
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92+
return null;
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}
94+
}

‎Stellar.Uno/Extensions/BuilderExtensions.cs‎

Lines changed: 7 additions & 2 deletions
Original file line numberDiff line numberDiff line change
@@ -30,11 +30,16 @@ public static IServiceCollection UseStellarComponents(this IServiceCollection se
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"UseStellarComponents must be called from the UI thread so the DispatcherQueue can be captured.");
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3232
// There is no ReactiveUI 24-compatible Uno platform package, so the activation
33-
// fetcher and schedulers are registered here directly, mirroring Stellar.Avalonia.
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// fetcher, DependencyProperty observation and schedulers are registered here
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// directly, mirroring Stellar.Avalonia.
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RxAppBuilder
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.CreateReactiveUIBuilder()
3637
.WithRegistration(
37-
static resolver => resolver.RegisterConstant<IActivationForViewFetcher>(new UnoActivationForViewFetcher()))
38+
static resolver =>
39+
{
40+
resolver.RegisterConstant<IActivationForViewFetcher>(new UnoActivationForViewFetcher());
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resolver.RegisterConstant<ICreatesObservableForProperty>(new DependencyObjectObservableForProperty());
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})
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.WithMainThreadScheduler(new UnoScheduler(dispatcherQueue))
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.WithTaskPoolScheduler(Schedulers.ShortTermThreadPoolScheduler)
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.Build();

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