CompiledBinding correctly locates IDataContextProvider as anchor.

src/Markup/Avalonia.Markup.Xaml/Extensions.cs

@@ -2,7 +2,9 @@
 using System.Collections.Generic;
 using System.ComponentModel;
 using System.Linq;
+using Avalonia.Controls;
 using Avalonia.Markup.Xaml.XamlIl.Runtime;
+using Avalonia.Styling;
 
 namespace Avalonia.Markup.Xaml
 {
@@ -32,5 +34,26 @@ public static Type ResolveType(this IServiceProvider ctx, string namespacePrefix
             string name = string.IsNullOrEmpty(namespacePrefix) ? type : $"{namespacePrefix}:{type}";
             return tr?.Resolve(name);
         }
+
+        public static object GetDefaultAnchor(this IServiceProvider provider)
+        {
+            // If the target is not a control, so we need to find an anchor that will let us look
+            // up named controls and style resources. First look for the closest IControl in
+            // the context.
+            object anchor = provider.GetFirstParent<IControl>();
+
+            if (anchor is null)
+            {
+                // Try to find IDataContextProvider, this was added to allow us to find
+                // a datacontext for Application class when using NativeMenuItems.
+                anchor = provider.GetFirstParent<IDataContextProvider>();
+            }
+
+            // If a control was not found, then try to find the highest-level style as the XAML
+            // file could be a XAML file containing only styles.
+            return anchor ??
+                   provider.GetService<IRootObjectProvider>()?.RootObject as IStyle ??
+                   provider.GetLastParent<IStyle>();
+        }
     }
 }

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

@@ -1,7 +1,5 @@
 using System;
 using Avalonia.Data;
-using Avalonia.Controls;
-using Avalonia.Styling;
 using Avalonia.Markup.Xaml.MarkupExtensions.CompiledBindings;
 using Avalonia.Data.Core;
 using Avalonia.Markup.Parsers;
@@ -33,24 +31,10 @@ public CompiledBindingExtension ProvideValue(IServiceProvider provider)
                 Priority = Priority,
                 StringFormat = StringFormat,
                 Source = Source,
-                DefaultAnchor = new WeakReference(GetDefaultAnchor(provider))
+                DefaultAnchor = new WeakReference(provider.GetDefaultAnchor())
             };
         }
 
-        private static object GetDefaultAnchor(IServiceProvider provider)
-        {
-            // If the target is not a control, so we need to find an anchor that will let us look
-            // up named controls and style resources. First look for the closest IControl in
-            // the context.
-            object anchor = provider.GetFirstParent<IControl>();
-
-            // If a control was not found, then try to find the highest-level style as the XAML
-            // file could be a XAML file containing only styles.
-            return anchor ??
-                    provider.GetService<IRootObjectProvider>()?.RootObject as IStyle ??
-                    provider.GetLastParent<IStyle>();
-        }
-
         protected override ExpressionObserver CreateExpressionObserver(IAvaloniaObject target, AvaloniaProperty targetProperty, object anchor, bool enableDataValidation)
         {
             if (Source != null)

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

@@ -37,33 +37,12 @@ public Binding ProvideValue(IServiceProvider serviceProvider)
                 Source = Source,
                 StringFormat = StringFormat,
                 RelativeSource = RelativeSource,
-                DefaultAnchor = new WeakReference(GetDefaultAnchor(descriptorContext)),
+                DefaultAnchor = new WeakReference(descriptorContext.GetDefaultAnchor()),
                 TargetNullValue = TargetNullValue,
                 NameScope = new WeakReference<INameScope>(serviceProvider.GetService<INameScope>())
             };
         }
 
-        private static object GetDefaultAnchor(IServiceProvider context)
-        {
-            // If the target is not a control, so we need to find an anchor that will let us look
-            // up named controls and style resources. First look for the closest IControl in
-            // the context.
-            object anchor = context.GetFirstParent<IControl>();
-
-            if(anchor is null)
-            {
-                // Try to find IDataContextProvider, this was added to allow us to find
-                // a datacontext for Application class when using NativeMenuItems.
-                anchor = context.GetFirstParent<IDataContextProvider>();
-            }
-
-            // If a control was not found, then try to find the highest-level style as the XAML
-            // file could be a XAML file containing only styles.
-            return anchor ??
-                    context.GetService<IRootObjectProvider>()?.RootObject as IStyle ??
-                    context.GetLastParent<IStyle>();
-        }
-
         public IValueConverter Converter { get; set; }
 
         public object ConverterParameter { get; set; }