Remove AutoCompleteBox.BindingEvaluator (#20596)

* Remove AutoCompleteBox.BindingEvaluator

* Fix AutoCompleteBoxPage sample

* Update API suppressions

api/Avalonia.nupkg.xml

@@ -31,6 +31,12 @@
     <Left>baseline/Avalonia/lib/net10.0/Avalonia.Base.dll</Left>
     <Right>current/Avalonia/lib/net10.0/Avalonia.Base.dll</Right>
   </Suppression>
+  <Suppression>
+    <DiagnosticId>CP0001</DiagnosticId>
+    <Target>T:Avalonia.Controls.AutoCompleteBox.BindingEvaluator`1</Target>
+    <Left>baseline/Avalonia/lib/net10.0/Avalonia.Controls.dll</Left>
+    <Right>current/Avalonia/lib/net10.0/Avalonia.Controls.dll</Right>
+  </Suppression>
   <Suppression>
     <DiagnosticId>CP0001</DiagnosticId>
     <Target>T:Avalonia.Controls.NativeMenuItemToggleType</Target>
@@ -79,6 +85,12 @@
     <Left>baseline/Avalonia/lib/net8.0/Avalonia.Base.dll</Left>
     <Right>current/Avalonia/lib/net8.0/Avalonia.Base.dll</Right>
   </Suppression>
+  <Suppression>
+    <DiagnosticId>CP0001</DiagnosticId>
+    <Target>T:Avalonia.Controls.AutoCompleteBox.BindingEvaluator`1</Target>
+    <Left>baseline/Avalonia/lib/net8.0/Avalonia.Controls.dll</Left>
+    <Right>current/Avalonia/lib/net8.0/Avalonia.Controls.dll</Right>
+  </Suppression>
   <Suppression>
     <DiagnosticId>CP0001</DiagnosticId>
     <Target>T:Avalonia.Controls.NativeMenuItemToggleType</Target>

samples/ControlCatalog/Pages/AutoCompleteBoxPage.xaml.cs

@@ -7,30 +7,12 @@ using Avalonia.Controls;
 using Avalonia.Data;
 using Avalonia.Data.Converters;
 using Avalonia.LogicalTree;
+using ControlCatalog.Models;
 
 namespace ControlCatalog.Pages
 {
     public partial class AutoCompleteBoxPage : UserControl
     {
-        public class StateData
-        {
-            public string Name { get; private set; }
-            public string Abbreviation { get; private set; }
-            public string Capital { get; private set; }
-
-            public StateData(string name, string abbreviatoin, string capital)
-            {
-                Name = name;
-                Abbreviation = abbreviatoin;
-                Capital = capital;
-            }
-
-            public override string ToString()
-            {
-                return Name;
-            }
-        }
-
         private static StateData[] BuildAllStates()
         {
             return new StateData[]

src/Avalonia.Controls/AutoCompleteBox/AutoCompleteBox.Properties.cs

@@ -191,6 +191,12 @@ namespace Avalonia.Controls
         public static readonly StyledProperty<object?> InnerRightContentProperty =
             TextBox.InnerRightContentProperty.AddOwner<AutoCompleteBox>();
 
+        /// <summary>
+        /// Defines the <see cref="ValueMemberBinding" /> property.
+        /// </summary>
+        public static readonly StyledProperty<BindingBase?> ValueMemberBindingProperty =
+            AvaloniaProperty.Register<AutoCompleteBox, BindingBase?>(nameof(ValueMemberBinding));
+
         /// <summary>
         /// Gets or sets the caret index
         /// </summary>
@@ -311,26 +317,16 @@ namespace Avalonia.Controls
         }
 
         /// <summary>
-        /// Gets or sets the  <see cref="T:Avalonia.Data.Binding" /> that
+        /// Gets or sets the  <see cref="BindingBase" /> that is used to get the values for display in the text portion
-        /// is used to get the values for display in the text portion of
+        /// of the <see cref="AutoCompleteBox" /> control.
-        /// the <see cref="AutoCompleteBox" />
-        /// control.
         /// </summary>
-        /// <value>The <see cref="T:Avalonia.Data.IBinding" /> object used
+        /// <value>The <see cref="T:Avalonia.Data.BindingBase" /> object used when binding to a collection property.</value>
-        /// when binding to a collection property.</value>
         [AssignBinding]
         [InheritDataTypeFromItems(nameof(ItemsSource))]
         public BindingBase? ValueMemberBinding
         {
-            get => _valueBindingEvaluator?.ValueBinding;
+            get => GetValue(ValueMemberBindingProperty);
-            set
+            set => SetValue(ValueMemberBindingProperty, value);
-            {
-                if (ValueMemberBinding != value)
-                {
-                    _valueBindingEvaluator = new BindingEvaluator<string>(value);
-                    OnValueMemberBindingChanged(value);
-                }
-            }
         }
 
         /// <summary>

src/Avalonia.Controls/AutoCompleteBox/AutoCompleteBox.cs

@@ -189,7 +189,7 @@ namespace Avalonia.Controls
         /// <summary>
         /// A control that can provide updated string values from a binding.
         /// </summary>
-        private BindingEvaluator<string>? _valueBindingEvaluator;
+        private BindingEvaluator<string?>? _valueMemberBindingEvaluator;
 
         /// <summary>
         /// A weak subscription for the collection changed event.
@@ -439,6 +439,7 @@ namespace Avalonia.Controls
             if (!_settingItemTemplateFromValueMemberBinding)
                 _itemTemplateIsFromValueMemberBinding = false;
         }
+
         private void OnValueMemberBindingChanged(BindingBase? value)
         {
             if (_itemTemplateIsFromValueMemberBinding)
@@ -460,6 +461,16 @@ namespace Avalonia.Controls
             }
         }
 
+        protected override void OnPropertyChanged(AvaloniaPropertyChangedEventArgs change)
+        {
+            base.OnPropertyChanged(change);
+
+            if (change.Property == ValueMemberBindingProperty)
+            {
+                OnValueMemberBindingChanged(change.GetNewValue<BindingBase?>());
+            }
+        }
+
         static AutoCompleteBox()
         {
             FocusableProperty.OverrideDefaultValue<AutoCompleteBox>(true);
@@ -1181,25 +1192,6 @@ namespace Avalonia.Controls
             }
         }
 
-        /// <summary>
-        /// Formats an Item for text comparisons based on Converter
-        /// and ConverterCulture properties.
-        /// </summary>
-        /// <param name="value">The object to format.</param>
-        /// <param name="clearDataContext">A value indicating whether to clear
-        /// the data context after the lookup is performed.</param>
-        /// <returns>Formatted Value.</returns>
-        private string? FormatValue(object? value, bool clearDataContext)
-        {
-            string? result = FormatValue(value);
-            if (clearDataContext && _valueBindingEvaluator != null)
-            {
-                _valueBindingEvaluator.ClearDataContext();
-            }
-
-            return result;
-        }
-
         /// <summary>
         /// Converts the specified object to a string by using the
         /// <see cref="P:Avalonia.Data.Binding.Converter" /> and
@@ -1215,9 +1207,13 @@ namespace Avalonia.Controls
         /// </remarks>
         protected virtual string? FormatValue(object? value)
         {
-            if (_valueBindingEvaluator != null)
+            if (ValueMemberBinding is { } valueMemberBinding)
             {
-                return _valueBindingEvaluator.GetDynamicValue(value) ?? String.Empty;
+                _valueMemberBindingEvaluator ??= new();
+                _valueMemberBindingEvaluator.UpdateBinding(valueMemberBinding);
+                var result = _valueMemberBindingEvaluator.Evaluate(value) ?? string.Empty;
+                _valueMemberBindingEvaluator.ClearDataContext();
+                return result;
             }
 
             return value == null ? String.Empty : value.ToString();
@@ -1451,9 +1447,6 @@ namespace Avalonia.Controls
 
                 _view?.Clear();
                 _view?.AddRange(_newViewItems);
-
-                // Clear the evaluator to discard a reference to the last item
-                _valueBindingEvaluator?.ClearDataContext();
             }
             finally
             {
@@ -1638,7 +1631,7 @@ namespace Avalonia.Controls
                         if (top != null)
                         {
                             newSelectedItem = top;
-                            string? topString = FormatValue(top, true);
+                            string? topString = FormatValue(top);
 
                             // Only replace partially when the two words being the same
                             int minLength = Math.Min(topString?.Length ?? 0, Text?.Length ?? 0);
@@ -1744,7 +1737,7 @@ namespace Avalonia.Controls
             }
             else if (TextSelector != null)
             {
-                text = TextSelector(SearchText, FormatValue(newItem, true));
+                text = TextSelector(SearchText, FormatValue(newItem));
             }
             else if (ItemSelector != null)
             {
@@ -1752,7 +1745,7 @@ namespace Avalonia.Controls
             }
             else
             {
-                text = FormatValue(newItem, true);
+                text = FormatValue(newItem);
             }
 
             // Update the Text property and the TextBox values
@@ -2020,109 +2013,5 @@ namespace Avalonia.Controls
                 return string.Equals(value, text, StringComparison.Ordinal);
             }
         }
-
-        // TODO12: Remove, this shouldn't be part of the public API. Use our internal BindingEvaluator instead.
-        /// <summary>
-        /// A framework element that permits a binding to be evaluated in a new data
-        /// context leaf node.
-        /// </summary>
-        /// <typeparam name="T">The type of dynamic binding to return.</typeparam>
-        public class BindingEvaluator<T> : Control
-        {
-            /// <summary>
-            /// Gets or sets the string value binding used by the control.
-            /// </summary>
-            private BindingBase? _binding;
-
-            /// <summary>
-            /// Identifies the Value dependency property.
-            /// </summary>
-            [System.Diagnostics.CodeAnalysis.SuppressMessage("AvaloniaProperty", "AVP1002:AvaloniaProperty objects should not be owned by a generic type",
-                Justification = "This property is not supposed to be used from XAML.")]
-            public static readonly StyledProperty<T> ValueProperty =
-                AvaloniaProperty.Register<BindingEvaluator<T>, T>(nameof(Value));
-
-            /// <summary>
-            /// Gets or sets the data item value.
-            /// </summary>
-            public T Value
-            {
-                get => GetValue(ValueProperty);
-                set => SetValue(ValueProperty, value);
-            }
-
-            /// <summary>
-            /// Gets or sets the value binding.
-            /// </summary>
-            public BindingBase? ValueBinding
-            {
-                get => _binding;
-                set
-                {
-                    _binding = value;
-                    if (value is not null)
-                        Bind(ValueProperty, value);
-                }
-            }
-
-            /// <summary>
-            /// Initializes a new instance of the BindingEvaluator class.
-            /// </summary>
-            public BindingEvaluator()
-            { }
-
-            /// <summary>
-            /// Initializes a new instance of the BindingEvaluator class,
-            /// setting the initial binding to the provided parameter.
-            /// </summary>
-            /// <param name="binding">The initial string value binding.</param>
-            public BindingEvaluator(BindingBase? binding)
-                : this()
-            {
-                ValueBinding = binding;
-            }
-
-            /// <summary>
-            /// Clears the data context so that the control does not keep a
-            /// reference to the last-looked up item.
-            /// </summary>
-            public void ClearDataContext()
-            {
-                DataContext = null;
-            }
-
-            /// <summary>
-            /// Updates the data context of the framework element and returns the
-            /// updated binding value.
-            /// </summary>
-            /// <param name="o">The object to use as the data context.</param>
-            /// <param name="clearDataContext">If set to true, this parameter will
-            /// clear the data context immediately after retrieving the value.</param>
-            /// <returns>Returns the evaluated T value of the bound dependency
-            /// property.</returns>
-            public T GetDynamicValue(object o, bool clearDataContext)
-            {
-                DataContext = o;
-                T value = Value;
-                if (clearDataContext)
-                {
-                    DataContext = null;
-                }
-                return value;
-            }
-
-            /// <summary>
-            /// Updates the data context of the framework element and returns the
-            /// updated binding value.
-            /// </summary>
-            /// <param name="o">The object to use as the data context.</param>
-            /// <returns>Returns the evaluated T value of the bound dependency
-            /// property.</returns>
-            public T GetDynamicValue(object? o)
-            {
-                DataContext = o;
-                return Value;
-            }
-        }
     }
 }