Update IResourceNode interface

samples/IntegrationTestApp/App.axaml

@@ -2,6 +2,6 @@
              xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
              x:Class="IntegrationTestApp.App">
     <Application.Styles>
-        <FluentTheme Mode="Light"/>
+        <FluentTheme />
     </Application.Styles>
 </Application>

samples/Sandbox/App.axaml

@@ -3,6 +3,6 @@
     xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
     x:Class="Sandbox.App">
     <Application.Styles>
-        <FluentTheme Mode="Dark"/>
+        <FluentTheme />
     </Application.Styles>
 </Application>

src/Avalonia.Base/Controls/IResourceDictionary.cs

@@ -14,6 +14,9 @@ public interface IResourceDictionary : IResourceProvider, IDictionary<object, ob
         /// </summary>
         IList<IResourceProvider> MergedDictionaries { get; }
 
+        /// <summary>
+        /// Gets a collection of merged resource dictionaries that are specifically keyed and composed to address theme scenarios.
+        /// </summary>
         IDictionary<ElementTheme, IResourceProvider> ThemeDictionaries { get; }
     }
 }

src/Avalonia.Base/Controls/IResourceNode.cs

@@ -1,5 +1,4 @@
-using System;
-using Avalonia.Metadata;
+using Avalonia.Metadata;
 
 namespace Avalonia.Controls
 {
@@ -23,15 +22,14 @@ public interface IResourceNode
         /// Tries to find a resource within the object.
         /// </summary>
         /// <param name="key">The resource key.</param>
+        /// <param name="theme">Theme used to select theme dictionary.</param>
         /// <param name="value">
         /// When this method returns, contains the value associated with the specified key,
         /// if the key is found; otherwise, null.
         /// </param>
         /// <returns>
         /// True if the resource if found, otherwise false.
         /// </returns>
-        bool TryGetResource(object key, out object? value);
-
-        bool TryGetResource(ElementTheme theme, object key, out object? value);
+        bool TryGetResource(object key, ElementTheme? theme, out object? value);
     }
 }

src/Avalonia.Base/Controls/ResourceDictionary.cs

@@ -132,44 +132,24 @@ bool IResourceNode.HasResources
 
         public event EventHandler? OwnerChanged;
 
-        public bool TryGetResource(object key, out object? value)
+        /// <inheritdoc/>
+        public bool TryGetResource(object key, ElementTheme? theme, out object? value)
         {
             if (TryGetValue(key, out value))
             {
                 return true;
             }
 
-            if (_mergedDictionaries != null)
-            {
-                for (var i = _mergedDictionaries.Count - 1; i >= 0; --i)
-                {
-                    if (_mergedDictionaries[i].TryGetResource(key, out value))
-                    {
-                        return true;
-                    }
-                }
-            }
-
-            return false;
-        }
-
-        public bool TryGetResource(ElementTheme theme, object key, out object? value)
-        {
-            if (TryGetValue(key, out value))
-            {
-                return true;
-            }
-
-            if (_themeDictionary is not null)
+            if (_themeDictionary is not null && theme is not null)
             {
                 if (_themeDictionary.TryGetValue(theme, out var themeResourceProvider)
-                    && themeResourceProvider.TryGetResource(key, out value))
+                    && themeResourceProvider.TryGetResource(key, theme, out value))
                 {
                     return true;
                 }
                 if (theme.InheritTheme is {} themeInherit
                     && _themeDictionary.TryGetValue(themeInherit, out themeResourceProvider)
-                    && themeResourceProvider.TryGetResource(key, out value))
+                    && themeResourceProvider.TryGetResource(key, theme, out value))
                 {
                     return true;
                 }
@@ -179,7 +159,7 @@ public bool TryGetResource(ElementTheme theme, object key, out object? value)
             {
                 for (var i = _mergedDictionaries.Count - 1; i >= 0; --i)
                 {
-                    if (_mergedDictionaries[i].TryGetResource(theme, key, out value))
+                    if (_mergedDictionaries[i].TryGetResource(key, theme, out value))
                     {
                         return true;
                     }

src/Avalonia.Base/Controls/ResourceNodeExtensions.cs

@@ -1,5 +1,4 @@
 using System;
-using Avalonia.LogicalTree;
 using Avalonia.Reactive;
 
 #nullable enable
@@ -39,38 +38,51 @@ public static bool TryFindResource(this IResourceHost control, object key, out o
             control = control ?? throw new ArgumentNullException(nameof(control));
             key = key ?? throw new ArgumentNullException(nameof(key));
 
-            IResourceNode? current = control;
+            var theme = AvaloniaLocator.Current.GetService<IApplicationThemeHost>()?.Theme;
 
-            while (current != null)
-            {
-                if (current.TryGetResource(key, out value))
-                {
-                    return true;
-                }
+            return control.TryFindResource(key, theme, out value);
+        }
+
+        /// <summary>
+        /// Finds the specified resource by searching up the logical tree and then global styles.
+        /// </summary>
+        /// <param name="control">The control.</param>
+        /// <param name="theme">Theme used to select theme dictionary.</param>
+        /// <param name="key">The resource key.</param>
+        /// <returns>The resource, or <see cref="AvaloniaProperty.UnsetValue"/> if not found.</returns>
+        public static object? FindResource(this IResourceHost control, ElementTheme? theme, object key)
+        {
+            control = control ?? throw new ArgumentNullException(nameof(control));
+            key = key ?? throw new ArgumentNullException(nameof(key));
 
-                current = (current as IStyledElement)?.StylingParent as IResourceNode;
+            if (control.TryFindResource(key, theme, out var value))
+            {
+                return value;
             }
 
-            value = null;
-            return false;
+            return AvaloniaProperty.UnsetValue;
         }
-
-        public static bool TryFindThemeResource(this IResourceHost control, ElementTheme theme, object key, out object? value)
+
+        /// <summary>
+        /// Tries to the specified resource by searching up the logical tree and then global styles.
+        /// </summary>
+        /// <param name="control">The control.</param>
+        /// <param name="key">The resource key.</param>
+        /// <param name="theme">Theme used to select theme dictionary.</param>
+        /// <param name="value">On return, contains the resource if found, otherwise null.</param>
+        /// <returns>True if the resource was found; otherwise false.</returns>
+        public static bool TryFindResource(this IResourceHost control, object key, ElementTheme? theme, out object? value)
         {
             control = control ?? throw new ArgumentNullException(nameof(control));
-            theme = theme ?? throw new ArgumentNullException(nameof(theme));
             key = key ?? throw new ArgumentNullException(nameof(key));
 
             IResourceHost? current = control;
 
             while (current != null)
             {
-                if (current is IResourceHost host)
+                if (current.TryGetResource(key, theme, out value))
                 {
-                    if (host.TryGetResource(theme, key, out value))
-                    {
-                        return true;
-                    }
+                    return true;
                 }
 
                 current = (current as IStyledElement)?.StylingParent as IResourceHost;
@@ -79,6 +91,17 @@ public static bool TryFindThemeResource(this IResourceHost control, ElementTheme
             value = null;
             return false;
         }
+
+        /// <inheritdoc cref="IResourceHost.TryGetResource" />
+        public static bool TryGetResource(this IResourceHost control, object key, out object? value)
+        {
+            control = control ?? throw new ArgumentNullException(nameof(control));
+            key = key ?? throw new ArgumentNullException(nameof(key));
+
+            var theme = AvaloniaLocator.Current.GetService<IApplicationThemeHost>()?.Theme;
+
+            return control.TryGetResource(key, theme, out value);
+        }
 
         public static IObservable<object?> GetResourceObservable(
             this IResourceHost control,
@@ -151,8 +174,7 @@ private void ThemeChanged(object? sender, EventArgs e)
             private object? GetValue()
             {
                 if (!(_target is IThemeStyleable themeStyleable)
-                    || themeStyleable.Theme is null
-                    || !themeStyleable.TryFindThemeResource(themeStyleable.Theme, _key, out var value))
+                    || !themeStyleable.TryFindResource(_key, themeStyleable.Theme, out var value))
                 {
                     value = _target.FindResource(_key) ?? AvaloniaProperty.UnsetValue;
                 }
@@ -242,7 +264,7 @@ private void ThemeChanged(object? sender, EventArgs e)
             {
                 if (!(_target.Owner is IThemeStyleable themeStyleable)
                     || themeStyleable.Theme is null
-                    || !themeStyleable.TryFindThemeResource(themeStyleable.Theme, _key, out var value))
+                    || !themeStyleable.TryFindResource(_key, themeStyleable.Theme, out var value))
                 {
                     value = _target.Owner?.FindResource(_key) ?? AvaloniaProperty.UnsetValue;
                 }

src/Avalonia.Base/StyledElement.cs

@@ -396,18 +396,11 @@ void ILogical.NotifyDetachedFromLogicalTree(LogicalTreeAttachmentEventArgs e)
         void IResourceHost.NotifyHostedResourcesChanged(ResourcesChangedEventArgs e) => NotifyResourcesChanged(e);
 
         /// <inheritdoc/>
-        bool IResourceNode.TryGetResource(object key, out object? value)
+        public bool TryGetResource(object key, ElementTheme? theme, out object? value)
         {
             value = null;
-            return (_resources?.TryGetResource(key, out value) ?? false) ||
-                   (_styles?.TryGetResource(key, out value) ?? false);
-        }
-
-        public bool TryGetResource(ElementTheme theme, object key, out object? value)
-        {
-            value = null;
-            return (_resources?.TryGetResource(theme, key, out value) ?? false) ||
-                   (_styles?.TryGetResource(theme, key, out value) ?? false);
+            return (_resources?.TryGetResource(key, theme, out value) ?? false) ||
+                   (_styles?.TryGetResource(key, theme, out value) ?? false);
         }
 
         /// <summary>

src/Avalonia.Base/Styling/Style.cs

@@ -110,17 +110,12 @@ public SelectorMatchResult TryAttach(IStyleable target, IStyleHost? host)
 
             return match.Result;
         }
-
-        public bool TryGetResource(object key, out object? result)
-        {
-            result = null;
-            return _resources?.TryGetResource(key, out result) ?? false;
-        }
-
-        public bool TryGetResource(ElementTheme theme, object key, out object? result)
+
+        /// <inheritdoc/>
+        public bool TryGetResource(object key, ElementTheme? theme, out object? result)
         {
             result = null;
-            return _resources?.TryGetResource(theme, key, out result) ?? false;
+            return _resources?.TryGetResource(key, theme, out result) ?? false;
         }
 
         /// <summary>

src/Avalonia.Base/Styling/Styles.cs

@@ -151,35 +151,16 @@ public SelectorMatchResult TryAttach(IStyleable target, IStyleHost? host)
         }
 
         /// <inheritdoc/>
-        public bool TryGetResource(object key, out object? value)
+        public bool TryGetResource(object key, ElementTheme? theme, out object? value)
         {
-            if (_resources != null && _resources.TryGetResource(key, out value))
+            if (_resources != null && _resources.TryGetResource(key, theme, out value))
             {
                 return true;
             }
 
             for (var i = Count - 1; i >= 0; --i)
             {
-                if (this[i].TryGetResource(key, out value))
-                {
-                    return true;
-                }
-            }
-
-            value = null;
-            return false;
-        }
-
-        public bool TryGetResource(ElementTheme theme, object key, out object? value)
-        {
-            if (_resources != null && _resources.TryGetResource(theme, key, out value))
-            {
-                return true;
-            }
-
-            for (var i = Count - 1; i >= 0; --i)
-            {
-                if (this[i] is IResourceProvider p && p.TryGetResource(theme, key, out value))
+                if (this[i] is IResourceProvider p && p.TryGetResource(key, theme, out value))
                 {
                     return true;
                 }

src/Avalonia.Base/Themes/ElementTheme.cs

@@ -11,7 +11,7 @@ public ElementTheme(object key)
         Key = key ?? throw new ArgumentNullException(nameof(key));
     }
 
-    public ElementTheme(object key, ElementTheme inheritTheme)
+    public ElementTheme(object key, ElementTheme? inheritTheme)
     {
         Key = key ?? throw new ArgumentNullException(nameof(key));
         InheritTheme = inheritTheme;

src/Avalonia.Controls/Application.cs

@@ -210,18 +210,11 @@ event Action<IReadOnlyList<IStyle>>? IGlobalStyles.GlobalStylesRemoved
         public virtual void Initialize() { }
 
         /// <inheritdoc/>
-        bool IResourceNode.TryGetResource(object key, out object? value)
+        public bool TryGetResource(object key, ElementTheme? theme, out object? value)
         {
             value = null;
-            return (_resources?.TryGetResource(key, out value) ?? false) ||
-                   Styles.TryGetResource(key, out value);
-        }
-
-        public bool TryGetResource(ElementTheme theme, object key, out object? value)
-        {
-            value = null;
-            return (_resources?.TryGetResource(theme, key, out value) ?? false) ||
-                   Styles.TryGetResource(theme, key, out value);
+            return (_resources?.TryGetResource(key, theme, out value) ?? false) ||
+                   Styles.TryGetResource(key, theme, out value);
         }
 
         void IResourceHost.NotifyHostedResourcesChanged(ResourcesChangedEventArgs e)

src/Avalonia.Dialogs/ResourceSelectorConverter.cs

@@ -9,7 +9,7 @@ public class ResourceSelectorConverter : ResourceDictionary, IValueConverter
     {
         public object Convert(object key, Type targetType, object parameter, CultureInfo culture)
         {
-            TryGetResource((string)key, out var value);
+            TryGetResource((string)key, null, out var value);
             return value;
         }
 

src/Markup/Avalonia.Markup.Xaml/MarkupExtensions/ResourceInclude.cs

@@ -47,23 +47,12 @@ public event EventHandler OwnerChanged
             add => Loaded.OwnerChanged += value;
             remove => Loaded.OwnerChanged -= value;
         }
-
-        bool IResourceNode.TryGetResource(object key, out object? value)
-        {
-            if (!_isLoading)
-            {
-                return Loaded.TryGetResource(key, out value);                
-            }
-
-            value = null;
-            return false;
-        }
-
-        public bool TryGetResource(ElementTheme theme, object key, out object? value)
+
+        public bool TryGetResource(object key, ElementTheme? theme, out object? value)
         {
             if (!_isLoading)
             {
-                return Loaded.TryGetResource(theme, key, out value);
+                return Loaded.TryGetResource(key, theme, out value);
             }
 
             value = null;

src/Markup/Avalonia.Markup.Xaml/MarkupExtensions/StaticResourceExtension.cs

@@ -46,11 +46,7 @@ public object ProvideValue(IServiceProvider serviceProvider)
             {
                 if (parent is IResourceNode node)
                 {
-                    if (appTheme is not null && node.TryGetResource(appTheme, ResourceKey, out var value))
-                    {
-                        return ColorToBrushConverter.Convert(value, targetType);
-                    }
-                    if (node.TryGetResource(ResourceKey, out value))
+                    if (node.TryGetResource(ResourceKey, appTheme, out var value))
                     {
                         return ColorToBrushConverter.Convert(value, targetType);
                     }