Implement PickerHandler in WinUI

src/Compatibility/Core/src/WinUI/PickerRenderer.cs

@@ -125,6 +125,7 @@ void ControlOnOpenAnimationCompleted(object sender, EventArgs eventArgs)
 			}
 		}
 
+		[PortHandler]
 		void OnControlSelectionChanged(object sender, WSelectionChangedEventArgs e)
 		{
 			if (Element != null)
@@ -173,11 +174,13 @@ void StartAnimationRefresh()
 			});
 		}
 
+		[PortHandler]
 		void UpdateCharacterSpacing()
 		{
 			Control.CharacterSpacing = Element.CharacterSpacing.ToEm();
 		}
 
+		[PortHandler]
 		void UpdateFont()
 		{
 			if (Control == null)
@@ -211,17 +214,20 @@ void UpdateFont()
 			_fontApplied = true;
 		}
 
+		[PortHandler]
 		void UpdateSelectedIndex()
 		{
 			Control.SelectedIndex = Element.SelectedIndex;
 		}
 
+		[PortHandler]
 		void UpdateTextColor()
 		{
 			Color color = Element.TextColor;
 			Control.Foreground = color.IsDefault() ? (_defaultBrush ?? Maui.ColorExtensions.ToNative(color)) : Maui.ColorExtensions.ToNative(color);
 		}
 
+		[PortHandler]
 		void UpdateTitle()
 		{
 			Control.Header = null;

src/Core/src/Handlers/Picker/PickerHandler.Windows.cs

@@ -1,28 +1,74 @@
-using System;
-using Microsoft.UI.Xaml.Controls;
+#nullable enable
+using WBrush = Microsoft.UI.Xaml.Media.Brush;
+using WSelectionChangedEventArgs = Microsoft.UI.Xaml.Controls.SelectionChangedEventArgs;
 
 namespace Microsoft.Maui.Handlers
 {
-	public partial class PickerHandler : ViewHandler<IPicker, ComboBox>
+	public partial class PickerHandler : ViewHandler<IPicker, MauiComboBox>
 	{
-		protected override ComboBox CreateNativeView() => new ComboBox();
+		WBrush? _defaultForeground;
 
-		[MissingMapper]
-		public static void MapTitle(PickerHandler handler, IPicker view) { }
+		protected override MauiComboBox CreateNativeView()
+		{
+			var nativePicker = new MauiComboBox();
+
+			if (VirtualView != null)
+				nativePicker.ItemsSource = ((LockableObservableListWrapper)VirtualView.Items)._list;
+
+			return nativePicker;
+		}
 
-		[MissingMapper]
-		public static void MapSelectedIndex(PickerHandler handler, IPicker view) { }
+		protected override void ConnectHandler(MauiComboBox nativeView)
+		{
+			nativeView.SelectionChanged += OnControlSelectionChanged;
+		}
 
-		[MissingMapper]
-		public static void MapCharacterSpacing(PickerHandler handler, IPicker view) { }
+		protected override void DisconnectHandler(MauiComboBox nativeView)
+		{
+			nativeView.SelectionChanged -= OnControlSelectionChanged;
+		}
 
-		[MissingMapper]
-		public static void MapFont(PickerHandler handler, IPicker view) { }
+		protected override void SetupDefaults(MauiComboBox nativeView)
+		{
+			_defaultForeground = nativeView.Foreground;
 
-		[MissingMapper]
-		public static void MapTextColor(PickerHandler handler, IPicker view) { }
+			base.SetupDefaults(nativeView);
+		}
+
+		public static void MapTitle(PickerHandler handler, IPicker picker) 
+		{
+			handler.NativeView?.UpdateTitle(picker);
+		}
+
+		public static void MapSelectedIndex(PickerHandler handler, IPicker picker)
+		{
+			handler.NativeView?.UpdateSelectedIndex(picker);
+		}
+
+		public static void MapCharacterSpacing(PickerHandler handler, IPicker picker) 
+		{
+			handler.NativeView?.UpdateCharacterSpacing(picker);
+		}
+
+		public static void MapFont(PickerHandler handler, IPicker picker) 
+		{
+			var fontManager = handler.GetRequiredService<IFontManager>();
+
+			handler.NativeView?.UpdateFont(picker, fontManager);
+		}
+
+		public static void MapTextColor(PickerHandler handler, IPicker picker)
+		{
+			handler.NativeView?.UpdateTextColor(picker, handler._defaultForeground);
+		}
 
 		[MissingMapper]
 		public static void MapHorizontalTextAlignment(PickerHandler handler, IPicker view) { }
+
+		void OnControlSelectionChanged(object? sender, WSelectionChangedEventArgs e)
+		{
+			if (VirtualView != null && NativeView != null)
+				VirtualView.SelectedIndex = NativeView.SelectedIndex;
+		}
 	}
 }

src/Core/src/Platform/Windows/CharacterSpacingExtensions.cs

@@ -9,4 +9,4 @@ public static int ToEm(this double pt)
 			return Convert.ToInt32(pt * 0.0624f * 1000); // Coefficient for converting Pt to Em. The value is uniform spacing between characters, in units of 1/1000 of an em.
 		}
 	}
-}
+}

src/Core/src/Platform/Windows/ColorConverter.cs

@@ -0,0 +1,27 @@
+using System;
+using Microsoft.UI;
+using WBrush = Microsoft.UI.Xaml.Media.Brush;
+using WSolidColorBrush = Microsoft.UI.Xaml.Media.SolidColorBrush;
+
+namespace Microsoft.Maui
+{
+	public sealed class ColorConverter : UI.Xaml.Data.IValueConverter
+	{
+		public object Convert(object value, Type targetType, object parameter, string language)
+		{
+			var color = (Graphics.Color)value;
+			var defaultColorKey = (string)parameter;
+
+			WBrush defaultBrush = defaultColorKey != null ? 
+				(WBrush)UI.Xaml.Application.Current.Resources[defaultColorKey] : 
+				new WSolidColorBrush(Colors.Transparent);
+
+			return color.IsDefault() ? defaultBrush : color.ToNative();
+		}
+
+		public object ConvertBack(object value, Type targetType, object parameter, string language)
+		{
+			throw new NotImplementedException();
+		}
+	}
+}

src/Core/src/Platform/Windows/MauiCombobox.cs

@@ -0,0 +1,26 @@
+#nullable enable
+using Microsoft.UI.Xaml.Controls;
+
+namespace Microsoft.Maui
+{
+	public class MauiComboBox : ComboBox
+	{
+		public MauiComboBox()
+		{
+			DefaultStyleKey = typeof(MauiComboBox);
+
+			DropDownOpened += OnMauiComboBoxDropDownOpened;
+			SelectionChanged += OnMauiComboBoxSelectionChanged;
+		}
+
+		void OnMauiComboBoxDropDownOpened(object? sender, object e)
+		{
+			MinWidth = ActualWidth;
+		}
+
+		void OnMauiComboBoxSelectionChanged(object? sender, SelectionChangedEventArgs e)
+		{
+			MinWidth = 0;
+		}
+	}
+}

src/Core/src/Platform/Windows/PickerExtensions.cs

@@ -0,0 +1,43 @@
+#nullable enable
+using Microsoft.Maui.Graphics;
+using Microsoft.UI.Xaml.Controls;
+using WBrush = Microsoft.UI.Xaml.Media.Brush;
+
+namespace Microsoft.Maui
+{
+	public static class PickerExtensions
+	{
+		public static void UpdateTitle(this MauiComboBox nativeComboBox, IPicker picker)
+		{
+			nativeComboBox.Header = null;
+
+			nativeComboBox.HeaderTemplate = string.IsNullOrEmpty(picker.Title) ? null : 
+				(UI.Xaml.DataTemplate)UI.Xaml.Application.Current.Resources["ComboBoxHeader"];
+
+			nativeComboBox.DataContext = picker;
+		}
+		public static void UpdateTextColor(this MauiComboBox nativeComboBox, IPicker picker)
+		{
+			nativeComboBox.UpdateTextColor(picker, null);
+		}
+
+		public static void UpdateTextColor(this MauiComboBox nativeComboBox, IPicker picker, WBrush? defaultForeground)
+		{
+			Color color = picker.TextColor;
+			nativeComboBox.Foreground = color.IsDefault() ? (defaultForeground ?? color.ToNative()) : color.ToNative();
+		}
+
+		public static void UpdateSelectedIndex(this MauiComboBox nativeComboBox, IPicker picker)
+		{
+			nativeComboBox.SelectedIndex = picker.SelectedIndex;
+		}
+
+		public static void UpdateCharacterSpacing(this MauiComboBox nativeComboBox, IPicker picker)
+		{
+			nativeComboBox.CharacterSpacing = picker.CharacterSpacing.ToEm();
+		}
+
+		public static void UpdateFont(this MauiComboBox nativeComboBox, IPicker picker, IFontManager fontManager) =>
+			nativeComboBox.UpdateFont(picker.Font, fontManager);
+	}
+}