feat: implement SelectedItems property in MultiAutoCompleteBox and remove SelectedItem property

src/Ursa/Controls/AutoCompleteBox/MultiAutoCompleteBox.Properties.cs

@@ -78,16 +78,6 @@ public partial class MultiAutoCompleteBox
             AvaloniaProperty.Register<MultiAutoCompleteBox, bool>(
                 nameof(IsDropDownOpen));
 
-        /// <summary>
-        /// Identifies the <see cref="SelectedItem" /> property.
-        /// </summary>
-        /// <value>The identifier the <see cref="SelectedItem" /> property.</value>
-        public static readonly StyledProperty<object?> SelectedItemProperty =
-            AvaloniaProperty.Register<MultiAutoCompleteBox, object?>(
-                nameof(SelectedItem),
-                defaultBindingMode: BindingMode.TwoWay,
-                enableDataValidation: true);
-
         /// <summary>
         /// Identifies the <see cref="Text" /> property.
         /// </summary>
@@ -182,6 +172,16 @@ public partial class MultiAutoCompleteBox
         /// </summary>
         public static readonly StyledProperty<object?> InnerRightContentProperty =
             TextBox.InnerRightContentProperty.AddOwner<MultiAutoCompleteBox>();
+        
+        public static readonly StyledProperty<IList?> SelectedItemsProperty =
+            AvaloniaProperty.Register<MultiAutoCompleteBox, IList?>(
+                nameof(SelectedItems));
+        
+        public IList? SelectedItems
+        {
+            get => GetValue(SelectedItemsProperty);
+            set => SetValue(SelectedItemsProperty, value);
+        }
 
         /// <summary>
         /// Gets or sets the caret index
@@ -316,22 +316,6 @@ public partial class MultiAutoCompleteBox
             }
         }
 
-        /// <summary>
-        /// Gets or sets the selected item in the drop-down.
-        /// </summary>
-        /// <value>The selected item in the drop-down.</value>
-        /// <remarks>
-        /// If the IsTextCompletionEnabled property is true and text typed by
-        /// the user matches an item in the ItemsSource collection, which is
-        /// then displayed in the text box, the SelectedItem property will be
-        /// a null reference.
-        /// </remarks>
-        public object? SelectedItem
-        {
-            get => GetValue(SelectedItemProperty);
-            set => SetValue(SelectedItemProperty, value);
-        }
-
         /// <summary>
         /// Gets or sets the text in the text box portion of the
         /// <see cref="AutoCompleteBox" /> control.

src/Ursa/Controls/AutoCompleteBox/MultiAutoCompleteBox.cs

@@ -14,13 +14,14 @@ using Avalonia.Input;
 using Avalonia.Interactivity;
 using Avalonia.Threading;
 using Avalonia.VisualTree;
+using Irihi.Avalonia.Shared.Contracts;
 using Irihi.Avalonia.Shared.Helpers;
 using Ursa.Common;
 
 
 namespace Ursa.Controls;
 
-public partial class MultiAutoCompleteBox : TemplatedControl
+public partial class MultiAutoCompleteBox : TemplatedControl, IInnerContentControl
 {
     /// <summary>
     ///     Specifies the name of the selection adapter TemplatePart.
@@ -181,7 +182,7 @@ public partial class MultiAutoCompleteBox : TemplatedControl
         MinimumPopulateDelayProperty.Changed.AddClassHandler<MultiAutoCompleteBox>((x, e) =>
             x.OnMinimumPopulateDelayChanged(e));
         IsDropDownOpenProperty.Changed.AddClassHandler<MultiAutoCompleteBox>((x, e) => x.OnIsDropDownOpenChanged(e));
-        SelectedItemProperty.Changed.AddClassHandler<MultiAutoCompleteBox>((x, e) => x.OnSelectedItemPropertyChanged(e));
+        // SelectedItemProperty.Changed.AddClassHandler<MultiAutoCompleteBox>((x, e) => x.OnSelectedItemPropertyChanged(e));
         TextProperty.Changed.AddClassHandler<MultiAutoCompleteBox>((x, e) => x.OnTextPropertyChanged(e));
         SearchTextProperty.Changed.AddClassHandler<MultiAutoCompleteBox>((x, e) => x.OnSearchTextPropertyChanged(e));
         FilterModeProperty.Changed.AddClassHandler<MultiAutoCompleteBox>((x, e) => x.OnFilterModePropertyChanged(e));
@@ -589,7 +590,10 @@ public partial class MultiAutoCompleteBox : TemplatedControl
         BindingValueType state,
         Exception? error)
     {
-        if (property == TextProperty || property == SelectedItemProperty) DataValidationErrors.SetError(this, error);
+        if (property == TextProperty || property == SelectedItemProperty)
+        {
+            DataValidationErrors.SetError(this, error);
+        }
     }
 
     /// <summary>