fix: Adjust TextBox ScrollViewer workaround for Material TextBox to wrap properly

src/Uno.UI.RuntimeTests/Tests/Windows_UI_Xaml_Controls/Given_TextBox.cs

@@ -694,5 +694,63 @@ public async Task When_TextBox_ImeAction_Enter()
 			act.Should().NotThrow();
 		}
 #endif
+
+		[TestMethod]
+#if __SKIA__
+		[Ignore("Fails on Skia")]
+#endif
+		public async Task When_TextBox_Wrap_Custom_Style()
+		{
+			var page = new TextBox_Wrapping();
+			await UITestHelper.Load(page);
+
+			page.SUT.Text = "Short";
+			await WindowHelper.WaitForIdle();
+			var height1 = page.SUT.ActualHeight;
+
+			page.SUT.Text = "This is a very very very much longer text. This TextBox should now wrap and have a larger height.";
+			await WindowHelper.WaitForIdle();
+			var height2 = page.SUT.ActualHeight;
+
+			page.SUT.Text = "Short";
+			await WindowHelper.WaitForIdle();
+			var height3 = page.SUT.ActualHeight;
+
+			Assert.AreEqual(height1, height3);
+			height2.Should().BeGreaterThan(height1);
+		}
+
+		[TestMethod]
+#if __SKIA__ || __IOS__
+		[Ignore("Fails on Skia and iOS")]
+  		// On iOS, the failure is: AssertFailedException: Expected value to be greater than 1199.0, but found 1199.0.
+		// Since the number is large, it looks like the TextBox is taking the full height.
+#endif
+		public async Task When_TextBox_Wrap_Fluent()
+		{
+			var SUT = new TextBox()
+			{
+				Width = 200,
+				TextWrapping = TextWrapping.Wrap,
+				AcceptsReturn = true,
+			};
+
+			await UITestHelper.Load(SUT);
+
+			SUT.Text = "Short";
+			await WindowHelper.WaitForIdle();
+			var height1 = SUT.ActualHeight;
+
+			SUT.Text = "This is a very very very much longer text. This TextBox should now wrap and have a larger height.";
+			await WindowHelper.WaitForIdle();
+			var height2 = SUT.ActualHeight;
+
+			SUT.Text = "Short";
+			await WindowHelper.WaitForIdle();
+			var height3 = SUT.ActualHeight;
+
+			Assert.AreEqual(height1, height3);
+			height2.Should().BeGreaterThan(height1);
+		}
 	}
 }

src/Uno.UI.RuntimeTests/Tests/Windows_UI_Xaml_Controls/TextBox_Wrapping.xaml

@@ -0,0 +1,62 @@
+<Page
+    x:Class="Uno.UI.RuntimeTests.Tests.Windows_UI_Xaml_Controls.TextBox_Wrapping"
+    xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
+    xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
+    xmlns:local="using:Uno.UI.RuntimeTests.Tests.Windows_UI_Xaml_Controls"
+    xmlns:d="http://schemas.microsoft.com/expression/blend/2008"
+    xmlns:mc="http://schemas.openxmlformats.org/markup-compatibility/2006"
+    mc:Ignorable="d"
+    Background="{ThemeResource ApplicationPageBackgroundThemeBrush}">
+
+	<StackPanel>
+		<StackPanel.Resources>
+			<Style x:Key="TextBoxStyle" TargetType="TextBox">
+				<Setter Property="HorizontalContentAlignment" Value="Left" />
+				<Setter Property="VerticalContentAlignment" Value="Center" />
+
+
+				<Setter Property="MinHeight" Value="58" />
+
+				<Setter Property="Template">
+					<Setter.Value>
+						<ControlTemplate TargetType="TextBox">
+							<Grid x:Name="Root"
+						  Background="{TemplateBinding Background}"
+						  CornerRadius="{TemplateBinding CornerRadius}"
+                          Padding="{TemplateBinding Padding}">
+
+								<ScrollViewer x:Name="ContentElement"
+										  Background="Red"
+										  HorizontalScrollBarVisibility="{TemplateBinding ScrollViewer.HorizontalScrollBarVisibility}"
+										  HorizontalScrollMode="{TemplateBinding ScrollViewer.HorizontalScrollMode}"
+										  IsDeferredScrollingEnabled="{TemplateBinding ScrollViewer.IsDeferredScrollingEnabled}"
+										  IsHorizontalRailEnabled="{TemplateBinding ScrollViewer.IsHorizontalRailEnabled}"
+										  IsTabStop="False"
+										  IsVerticalRailEnabled="{TemplateBinding ScrollViewer.IsVerticalRailEnabled}"
+										  VerticalAlignment="{TemplateBinding VerticalContentAlignment}"
+										  VerticalScrollMode="{TemplateBinding ScrollViewer.VerticalScrollMode}"
+										  VerticalScrollBarVisibility="{TemplateBinding ScrollViewer.VerticalScrollBarVisibility}"
+										  ZoomMode="Disabled"
+										  AutomationProperties.AccessibilityView="Raw">
+								</ScrollViewer>
+
+							</Grid>
+						</ControlTemplate>
+					</Setter.Value>
+				</Setter>
+			</Style>
+		</StackPanel.Resources>
+		<StackPanel Margin="10" VerticalAlignment="Center" Width="200">
+			<TextBox AutomationProperties.AutomationId="NewTextBox"
+					 x:Name="SUT"
+					 x:FieldModifier="public"
+					 AcceptsReturn="True"
+					 IsSpellCheckEnabled="True"
+                     Margin="0,10"
+					 MaxLength="500"
+					 PlaceholderText="Enter text here"
+					 Style="{StaticResource TextBoxStyle}"
+					 TextWrapping="Wrap" />
+		</StackPanel>
+	</StackPanel>
+</Page>

src/Uno.UI.RuntimeTests/Tests/Windows_UI_Xaml_Controls/TextBox_Wrapping.xaml.cs

@@ -0,0 +1,11 @@
+using Windows.UI.Xaml.Controls;
+
+namespace Uno.UI.RuntimeTests.Tests.Windows_UI_Xaml_Controls;
+
+public sealed partial class TextBox_Wrapping : Page
+{
+	public TextBox_Wrapping()
+	{
+		this.InitializeComponent();
+	}
+}

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

@@ -87,12 +87,6 @@ private protected override void OnUnloaded()
 			}
 		}
 
-		private protected override void OnLoaded()
-		{
-			base.OnLoaded();
-			SetupTextBoxView();
-		}
-
 		partial void InitializePropertiesPartial()
 		{
 			OnImeOptionsChanged(ImeOptions);

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

@@ -118,6 +118,46 @@ public TextBox()
 			SizeChanged += OnSizeChanged;
 		}
 
+		private protected override void OnLoaded()
+		{
+			base.OnLoaded();
+
+#if __ANDROID__
+			SetupTextBoxView();
+#endif
+
+			// This workaround is added in OnLoaded rather than OnApplyTemplate.
+			// Apparently, sometimes (e.g, Material style), the TextBox style setters are executed after OnApplyTemplate
+			// So, the style setters would override what the workaround does.
+			// OnLoaded appears to be executed after both OnApplyTemplate and after the style setters, making sure the values set here are not modified after.
+			if (_contentElement is ScrollViewer scrollViewer)
+			{
+#if __IOS__ || __MACOS__
+				// We disable scrolling because the inner ITextBoxView provides its own scrolling
+				scrollViewer.HorizontalScrollMode = ScrollMode.Disabled;
+				scrollViewer.VerticalScrollMode = ScrollMode.Disabled;
+				scrollViewer.HorizontalScrollBarVisibility = ScrollBarVisibility.Disabled;
+				scrollViewer.VerticalScrollBarVisibility = ScrollBarVisibility.Disabled;
+#else
+				// The template of TextBox contains the following:
+				/*
+					HorizontalScrollBarVisibility="{TemplateBinding ScrollViewer.HorizontalScrollBarVisibility}"
+					HorizontalScrollMode="{TemplateBinding ScrollViewer.HorizontalScrollMode}"
+					VerticalScrollBarVisibility="{TemplateBinding ScrollViewer.VerticalScrollBarVisibility}"
+					VerticalScrollMode="{TemplateBinding ScrollViewer.VerticalScrollMode}"
+				 */
+				// Historically, TemplateBinding for attached DPs wasn't supported, and TextBox worked perfectly fine.
+				// When support for TemplateBinding for attached DPs was added, TextBox broke (test: TextBox_AutoGrow_Vertically_Wrapping_Test) because of
+				// change in the values of these properties. The following code serves as a workaround to set the values to what they used to be
+				// before the support for TemplateBinding for attached DPs.
+				scrollViewer.HorizontalScrollMode = ScrollMode.Enabled; // The template sets this to Auto
+				scrollViewer.VerticalScrollMode = ScrollMode.Enabled; // The template sets this to Auto
+				scrollViewer.HorizontalScrollBarVisibility = ScrollBarVisibility.Disabled; // The template sets this to Hidden
+				scrollViewer.VerticalScrollBarVisibility = ScrollBarVisibility.Auto; // The template sets this to Hidden
+#endif
+			}
+		}
+
 		internal bool IsUserModifying => _isInputModifyingText || _isInputClearingText;
 
 		private void OnSizeChanged(object sender, SizeChangedEventArgs args)
@@ -169,33 +209,6 @@ protected override void OnApplyTemplate()
 			_contentElement = GetTemplateChild(TextBoxConstants.ContentElementPartName) as ContentControl;
 			_header = GetTemplateChild(TextBoxConstants.HeaderContentPartName) as ContentPresenter;
 
-			if (_contentElement is ScrollViewer scrollViewer)
-			{
-#if __IOS__ || __MACOS__
-				// We disable scrolling because the inner ITextBoxView provides its own scrolling
-				scrollViewer.HorizontalScrollMode = ScrollMode.Disabled;
-				scrollViewer.VerticalScrollMode = ScrollMode.Disabled;
-				scrollViewer.HorizontalScrollBarVisibility = ScrollBarVisibility.Disabled;
-				scrollViewer.VerticalScrollBarVisibility = ScrollBarVisibility.Disabled;
-#else
-				// The template of TextBox contains the following:
-				/*
-					HorizontalScrollBarVisibility="{TemplateBinding ScrollViewer.HorizontalScrollBarVisibility}"
-					HorizontalScrollMode="{TemplateBinding ScrollViewer.HorizontalScrollMode}"
-					VerticalScrollBarVisibility="{TemplateBinding ScrollViewer.VerticalScrollBarVisibility}"
-					VerticalScrollMode="{TemplateBinding ScrollViewer.VerticalScrollMode}"
-				 */
-				// Historically, TemplateBinding for attached DPs wasn't supported, and TextBox worked perfectly fine.
-				// When support for TemplateBinding for attached DPs was added, TextBox broke (test: TextBox_AutoGrow_Vertically_Wrapping_Test) because of
-				// change in the values of these properties. The following code serves as a workaround to set the values to what they used to be
-				// before the support for TemplateBinding for attached DPs.
-				scrollViewer.HorizontalScrollMode = ScrollMode.Enabled; // The template sets this to Auto
-				scrollViewer.VerticalScrollMode = ScrollMode.Enabled; // The template sets this to Auto
-				scrollViewer.HorizontalScrollBarVisibility = ScrollBarVisibility.Disabled; // The template sets this to Hidden
-				scrollViewer.VerticalScrollBarVisibility = ScrollBarVisibility.Auto; // The template sets this to Hidden
-#endif
-			}
-
 			if (GetTemplateChild(TextBoxConstants.DeleteButtonPartName) is Button button)
 			{
 				_deleteButton = new WeakReference<Button>(button);