feat: Implement TextBox.Select, TextBox.SelectAll on all platforms

src/SamplesApp/UITests.Shared/UITests.Shared.projitems

@@ -1789,6 +1789,10 @@
       <SubType>Designer</SubType>
       <Generator>MSBuild:Compile</Generator>
     </Page>
+    <Page Include="$(MSBuildThisFileDirectory)Windows_UI_Xaml_Controls\TextBox\TextBox_Selection.xaml">
+      <SubType>Designer</SubType>
+      <Generator>MSBuild:Compile</Generator>
+    </Page>
     <Page Include="$(MSBuildThisFileDirectory)Windows_UI_Xaml_Controls\TextBox\TextBox_TextChanging.xaml">
       <SubType>Designer</SubType>
       <Generator>MSBuild:Compile</Generator>
@@ -5471,6 +5475,9 @@
     <Compile Include="$(MSBuildThisFileDirectory)Windows_UI_Xaml_Controls\TextBox\TextBox_RoundedCorners.xaml.cs">
       <DependentUpon>TextBox_RoundedCorners.xaml</DependentUpon>
     </Compile>
+    <Compile Include="$(MSBuildThisFileDirectory)Windows_UI_Xaml_Controls\TextBox\TextBox_Selection.xaml.cs">
+      <DependentUpon>TextBox_Selection.xaml</DependentUpon>
+    </Compile>
     <Compile Include="$(MSBuildThisFileDirectory)Windows_UI_Xaml_Controls\TextBox\TextBox_TextChanging.xaml.cs">
       <DependentUpon>TextBox_TextChanging.xaml</DependentUpon>
     </Compile>

src/SamplesApp/UITests.Shared/Windows_UI_Xaml_Controls/TextBox/TextBox_Selection.xaml

@@ -0,0 +1,20 @@
+<UserControl
+    x:Class="UITests.Shared.Windows_UI_Xaml_Controls.TextBoxTests.TextBox_Selection"
+    xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
+    xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
+    xmlns:local="using:UITests.Windows_UI_Xaml_Controls.TextBox"
+    xmlns:controls="using:Microsoft.UI.Xaml.Controls"
+    xmlns:d="http://schemas.microsoft.com/expression/blend/2008"
+    xmlns:mc="http://schemas.openxmlformats.org/markup-compatibility/2006"
+    mc:Ignorable="d"
+    d:DesignHeight="300"
+    d:DesignWidth="400">
+
+	<StackPanel>
+		<controls:NumberBox x:Name="startNumber" PlaceholderText="Start" />
+		<controls:NumberBox x:Name="lengthNumber" PlaceholderText="Length" />
+		<TextBox x:Name="myTextBox" />
+		<Button Click="Select_OnClick" Content="Select"></Button>
+		<Button Click="SelectAll_OnClick" Content="Select all"></Button>
+	</StackPanel>
+</UserControl>

src/SamplesApp/UITests.Shared/Windows_UI_Xaml_Controls/TextBox/TextBox_Selection.xaml.cs

@@ -0,0 +1,28 @@
+using Uno.UI.Samples.Controls;
+using Windows.UI.Xaml;
+using Windows.UI.Xaml.Controls;
+using static Uno.UI.FeatureConfiguration;
+
+
+namespace UITests.Shared.Windows_UI_Xaml_Controls.TextBoxTests
+{
+	[Sample("TextBox")]
+	public sealed partial class TextBox_Selection : UserControl
+	{
+		public TextBox_Selection()
+		{
+			this.InitializeComponent();
+		}
+		private void Select_OnClick(object sender, RoutedEventArgs args)
+		{
+			myTextBox.Focus(FocusState.Programmatic);
+			myTextBox.Select((int)startNumber.Value, (int)lengthNumber.Value);
+		}
+
+		private void SelectAll_OnClick(object sender, RoutedEventArgs args)
+		{
+			myTextBox.Focus(FocusState.Programmatic);
+			myTextBox.SelectAll();
+		}
+	}
+}

src/Uno.UI.Runtime.Skia.Gtk/UI/Xaml/Controls/TextBoxViewExtension.cs

@@ -288,5 +288,14 @@ public void SetIsPassword(bool isPassword)
 				entry.Visibility = !isPassword;
 			}
 		}
+
+		public void Select(int start, int length)
+		{
+			if (_currentInputWidget is Entry entry)
+			{
+				entry.SelectRegion(start_pos: start, end_pos: start + length);
+			}
+			// TODO: Handle TextView..
+		}
 	}
 }

src/Uno.UI.Runtime.Skia.Wpf/Extensions/UI/Xaml/Controls/TextBoxViewExtension.cs

@@ -187,5 +187,7 @@ public void SetIsPassword(bool isPassword)
 		{
 			// No support for now.
 		}
+
+		public void Select(int start, int length) => _currentInputWidget?.Select(start, length);
 	}
 }

src/Uno.UI/Generated/3.0.0.0/Windows.UI.Xaml.Controls/TextBox.cs

@@ -463,14 +463,14 @@ public  bool CanUndo
 		// Forced skipping of method Windows.UI.Xaml.Controls.TextBox.SelectionChanged.remove
 		// Forced skipping of method Windows.UI.Xaml.Controls.TextBox.ContextMenuOpening.add
 		// Forced skipping of method Windows.UI.Xaml.Controls.TextBox.ContextMenuOpening.remove
-		#if __ANDROID__ || __IOS__ || NET461 || __WASM__ || __SKIA__ || __NETSTD_REFERENCE__ || __MACOS__
+		#if false || false || false || false || false || false || false
 		[global::Uno.NotImplemented("__ANDROID__", "__IOS__", "NET461", "__WASM__", "__SKIA__", "__NETSTD_REFERENCE__", "__MACOS__")]
 		public  void Select( int start,  int length)
 		{
 			global::Windows.Foundation.Metadata.ApiInformation.TryRaiseNotImplemented("Windows.UI.Xaml.Controls.TextBox", "void TextBox.Select(int start, int length)");
 		}
 		#endif
-		#if __ANDROID__ || __IOS__ || NET461 || __WASM__ || __SKIA__ || __NETSTD_REFERENCE__ || __MACOS__
+		#if false || false || false || false || false || false || false
 		[global::Uno.NotImplemented("__ANDROID__", "__IOS__", "NET461", "__WASM__", "__SKIA__", "__NETSTD_REFERENCE__", "__MACOS__")]
 		public  void SelectAll()
 		{

src/Uno.UI/UI/Xaml/Controls/TextBox/ITextBoxExtension.skia.cs

@@ -17,5 +17,7 @@ internal interface ITextBoxViewExtension
 		void SetTextNative(string text);
 
 		void SetIsPassword(bool isPassword);
+
+		void Select(int start, int length);
 	}
 }

src/Uno.UI/UI/Xaml/Controls/TextBox/TextBox.Android.cs

@@ -122,7 +122,7 @@ public ImeAction ImeOptions
 			set { this.SetValue(ImeOptionsProperty, value); }
 		}
 
-		public static DependencyProperty ImeOptionsProperty { get ; } =
+		public static DependencyProperty ImeOptionsProperty { get; } =
 			DependencyProperty.Register("ImeOptions",
 				typeof(ImeAction),
 				typeof(TextBox),
@@ -188,6 +188,11 @@ public override bool RequestFocus(FocusSearchDirection direction, Rect previousl
 			}
 		}
 
+		partial void SelectPartial(int start, int length)
+			=> _textBoxView.SetSelection(start: start, stop: start + length);
+
+		public void SelectAll() => _textBoxView.SelectAll();
+
 		/// <summary>
 		/// Applies PreventKeyboardDisplayOnProgrammaticFocus by temporarily disabling soft input display.
 		/// </summary>

src/Uno.UI/UI/Xaml/Controls/TextBox/TextBox.cs

@@ -762,6 +762,37 @@ protected override void OnVerticalContentAlignmentChanged(VerticalAlignment oldV
 
 		partial void OnVerticalContentAlignmentChangedPartial(VerticalAlignment oldVerticalContentAlignment, VerticalAlignment newVerticalContentAlignment);
 
+		public void Select(int start, int length)
+		{
+			if (start < 0)
+			{
+				throw new ArgumentOutOfRangeException(nameof(start), $"'{start}' cannot be negative.");
+			}
+
+			if (length < 0)
+			{
+				throw new ArgumentOutOfRangeException(nameof(length), $"'{length}' cannot be negative.");
+			}
+
+			// TODO: Test and adjust (if needed) this logic for surrogate pairs.
+
+			var textLength = Text.Length;
+
+			if (start >= textLength)
+			{
+				start = textLength;
+				length = 0;
+			}
+			else if (start + length > textLength)
+			{
+				length = textLength - start;
+			}
+
+			SelectPartial(start, length);
+		}
+
+		partial void SelectPartial(int start, int length);
+
 		internal override bool CanHaveChildren() => true;
 	}
 }

src/Uno.UI/UI/Xaml/Controls/TextBox/TextBox.iOS.cs

@@ -71,6 +71,14 @@ partial void OnTextAlignmentChangedPartial(DependencyPropertyChangedEventArgs e)
 			_textBoxView?.UpdateTextAlignment();
 		}
 
+		partial void SelectPartial(int start, int length)
+		{
+			if (_textBoxView != null)
+			{
+				_textBoxView.SelectedTextRange = _textBoxView.GetTextRange(start: start, end: start + length);
+			}
+		}
+
 		internal MultilineTextBoxView MultilineTextBox
 		{
 			get
@@ -267,7 +275,7 @@ public UIReturnKeyType ReturnKeyType
 			set { SetValue(ReturnKeyTypeProperty, value); }
 		}
 
-		public static DependencyProperty ReturnKeyTypeProperty { get ; } =
+		public static DependencyProperty ReturnKeyTypeProperty { get; } =
 			DependencyProperty.Register(
 				"ReturnKeyType",
 				typeof(UIReturnKeyType),
@@ -304,7 +312,7 @@ public UIKeyboardAppearance KeyboardAppearance
 			set { SetValue(KeyboardAppearanceProperty, value); }
 		}
 
-		public static DependencyProperty KeyboardAppearanceProperty { get ; } =
+		public static DependencyProperty KeyboardAppearanceProperty { get; } =
 			DependencyProperty.Register(
 				"KeyboardAppearance",
 				typeof(UIKeyboardAppearance),

src/Uno.UI/UI/Xaml/Controls/TextBox/TextBox.macOS.cs

@@ -63,6 +63,14 @@ partial void OnTextAlignmentChangedPartial(DependencyPropertyChangedEventArgs e)
 		{
 		}
 
+		partial void SelectPartial(int start, int length)
+		{
+			if (_textBoxView != null)
+			{
+				_textBoxView.SelectedTextRange = _textBoxView.GetTextRange(start: start, end: start + length);
+			}
+		}
+
 		private void UpdateTextBoxView()
 		{
 			if (_contentElement != null)

src/Uno.UI/UI/Xaml/Controls/TextBox/TextBox.skia.cs

@@ -23,6 +23,13 @@ private void UpdateTextBoxView()
 
 		partial void OnFocusStateChangedPartial(FocusState focusState) => _textBoxView?.OnFocusStateChanged(focusState);
 
+		partial void SelectPartial(int start, int length)
+		{
+			_textBoxView?.Select(start, length);
+		}
+
+		public void SelectAll() => Select(0, Text.Length);
+
 		protected void SetIsPassword(bool isPassword) => _textBoxView?.SetIsPassword(isPassword);
 	}
 }

src/Uno.UI/UI/Xaml/Controls/TextBox/TextBox.wasm.cs

@@ -1,4 +1,5 @@
 using Uno.Extensions;
+using Uno.Foundation;
 using Windows.UI.Xaml.Input;
 using Windows.UI.Xaml.Media;
 
@@ -116,6 +117,13 @@ partial void OnIsReadonlyChangedPartial(DependencyPropertyChangedEventArgs e)
 
 		private void ApplyIsReadonly(bool? isReadOnly = null) => _textBoxView?.SetIsReadOnly(isReadOnly ?? IsReadOnly);
 
+		partial void SelectPartial(int start, int length)
+		{
+			_textBoxView?.Select(start, length);
+		}
+
+		public void SelectAll() => Select(0, Text.Length);
+
 		public int SelectionStart
 		{
 			get => _textBoxView?.SelectionStart ?? 0;

src/Uno.UI/UI/Xaml/Controls/TextBox/TextBoxView.skia.cs

@@ -63,6 +63,11 @@ internal void SetTextNative(string text)
 			_textBoxExtension?.SetTextNative(text);
 		}
 
+		internal void Select(int start, int length)
+		{
+			_textBoxExtension.Select(start, length);
+		}
+
 		internal void OnForegroundChanged(Brush brush) => DisplayBlock.Foreground = brush;
 
 		internal void OnFocusStateChanged(FocusState focusState)

src/Uno.UI/UI/Xaml/Controls/TextBox/TextBoxView.wasm.cs

@@ -8,6 +8,7 @@
 using Windows.Foundation;
 using System.Globalization;
 using Uno.Disposables;
+using Uno.Foundation;
 
 namespace Windows.UI.Xaml.Controls
 {
@@ -105,6 +106,9 @@ internal void SetTextNative(string text)
 			InvalidateMeasure();
 		}
 
+		internal void Select(int start, int length)
+			=> WebAssemblyRuntime.InvokeJS($"document.getElementById({HtmlId}).setSelectionRange({start}, {start + length})");
+
 		protected override Size MeasureOverride(Size availableSize) => MeasureView(availableSize);
 
 		internal void SetIsPassword(bool isPassword)