Set SelectedItemProperty when value is commit and bind it 2-way by default

Author: corvinsz

src/MaterialDesignThemes.Wpf/AutoSuggestBox.cs

@@ -96,7 +96,11 @@ public object SelectedItem
         set => SetValue(SelectedItemProperty, value);
     }
     public static readonly DependencyProperty SelectedItemProperty =
-        DependencyProperty.Register(nameof(SelectedItem), typeof(object), typeof(AutoSuggestBox), new PropertyMetadata(default(object)));
+        DependencyProperty.Register(
+            nameof(SelectedItem),
+            typeof(object),
+            typeof(AutoSuggestBox),
+            new FrameworkPropertyMetadata(default(object), FrameworkPropertyMetadataOptions.BindsTwoWayByDefault));
 
 
     public object SelectedValue
@@ -254,6 +258,7 @@ private bool CommitValueSelection(object? selectedValue)
         {
             CaretIndex = Text.Length;
         }
+        SetCurrentValue(SelectedItemProperty, selectedValue);
         CloseAutoSuggestionPopUp();
         var args = new RoutedPropertyChangedEventArgs<object?>(oldValue, Text)
         {

tests/MaterialDesignThemes.UITests/WPF/AutoSuggestBoxes/AutoSuggestTextBoxTests.cs

@@ -201,6 +201,33 @@ public async Task AutoSuggestBox_KeysUpAndDown_WrapAround()
         Assert.Equal(0, await suggestionListBox.GetSelectedIndex());
     }
 
+    [Fact]
+    [Description("Issue 3845")]
+    public async Task AutoSuggestBox_SelectingAnItem_SetsSelectedItem()
+    {
+        await using var recorder = new TestRecorder(App);
+
+        //Arrange
+        IVisualElement<AutoSuggestBox> suggestBox = (await LoadUserControl<AutoSuggestTextBoxWithTemplate>()).As<AutoSuggestBox>();
+        IVisualElement<Popup> popup = await suggestBox.GetElement<Popup>();
+        IVisualElement<ListBox> suggestionListBox = await popup.GetElement<ListBox>();
+
+        //Act
+        await suggestBox.MoveKeyboardFocus();
+        await Task.Delay(50);
+        await suggestBox.SendInput(new KeyboardInput("B"));
+        await Task.Delay(50);
+        await suggestBox.SendInput(new KeyboardInput(Key.Enter));
+        await Task.Delay(50);
+
+        //Assert
+        string? selectedItem = (await suggestBox.GetSelectedItem()) as string;
+        Assert.NotNull(selectedItem);
+        Assert.Equal("Bananas", selectedItem);
+
+        recorder.Success();
+    }
+
     private static async Task AssertExists(IVisualElement<ListBox> suggestionListBox, string text, bool existsOrNotCheck = true)
     {
         try