From 0f8027094ec0af7e89a2feac7a02d32fc8d23400 Mon Sep 17 00:00:00 2001
From: database64128 <free122448@hotmail.com>
Date: Sun, 28 Sep 2025 05:44:41 +0800
Subject: [PATCH] Fix TextBox horizontal scrollbar position when
 VerticalContentAlignment is set to Top

---
 src/MainDemo.Wpf/Fields.xaml                  |  6 ++--
 .../Converters/VerticalAlignmentConverter.cs  |  1 -
 .../Themes/MaterialDesignTheme.TextBox.xaml   |  9 +++---
 .../WPF/TextBoxes/TextBoxTests.cs             | 28 -------------------
 4 files changed, 9 insertions(+), 35 deletions(-)

diff --git a/src/MainDemo.Wpf/Fields.xaml b/src/MainDemo.Wpf/Fields.xaml
index 432e141ac0..c915a2057b 100644
--- a/src/MainDemo.Wpf/Fields.xaml
+++ b/src/MainDemo.Wpf/Fields.xaml
@@ -340,12 +340,14 @@
 
           <TextBox Height="100"
                    VerticalAlignment="Top"
+                   VerticalContentAlignment="Top"
                    materialDesign:HintAssist.Hint="This is a text area"
                    AcceptsReturn="True"
                    IsEnabled="{Binding Path=IsChecked, ElementName=MaterialDesignOutlinedTextBoxEnabledComboBox}"
                    Style="{StaticResource MaterialDesignOutlinedTextBox}"
-                   TextWrapping="Wrap"
-                   VerticalScrollBarVisibility="Auto" />
+                   TextWrapping="NoWrap"
+                   VerticalScrollBarVisibility="Auto"
+                   HorizontalScrollBarVisibility="Auto" />
         </StackPanel>
       </smtx:XamlDisplay>
 
diff --git a/src/MaterialDesignThemes.Wpf/Converters/VerticalAlignmentConverter.cs b/src/MaterialDesignThemes.Wpf/Converters/VerticalAlignmentConverter.cs
index d585cc1ab0..37e6291320 100644
--- a/src/MaterialDesignThemes.Wpf/Converters/VerticalAlignmentConverter.cs
+++ b/src/MaterialDesignThemes.Wpf/Converters/VerticalAlignmentConverter.cs
@@ -3,7 +3,6 @@
 
 namespace MaterialDesignThemes.Wpf.Converters;
 
-[Obsolete("This class is obsolete and will be removed in a future version.")]
 public class VerticalAlignmentConverter : IValueConverter
 {
     public VerticalAlignment StretchReplacement { get; set; } = VerticalAlignment.Top;
diff --git a/src/MaterialDesignThemes.Wpf/Themes/MaterialDesignTheme.TextBox.xaml b/src/MaterialDesignThemes.Wpf/Themes/MaterialDesignTheme.TextBox.xaml
index ea6ee70104..bf926e18ba 100644
--- a/src/MaterialDesignThemes.Wpf/Themes/MaterialDesignTheme.TextBox.xaml
+++ b/src/MaterialDesignThemes.Wpf/Themes/MaterialDesignTheme.TextBox.xaml
@@ -43,6 +43,7 @@
     <Style.Resources>
       <convertersInternal:TextFieldClearButtonVisibilityConverter x:Key="ClearButtonVisibilityConverter" ContentEmptyVisibility="Collapsed" />
       <converters:TextFieldPrefixTextVisibilityConverter x:Key="PrefixSuffixTextVisibilityConverter" HiddenState="Collapsed" />
+      <converters:VerticalAlignmentConverter x:Key="PrefixSuffixTextVerticalAlignmentConverter" StretchReplacement="Center" />
       <converters:BooleanToDashStyleConverter x:Key="BooleanToDashStyleConverter" TrueValue="{x:Static DashStyles.Solid}" />
       <converters:ThicknessCloneConverter x:Key="HelperTextMarginConverter" CloneEdges="Left,Right" />
       <converters:MathConverter x:Key="DivisionConverter" Operation="Divide" Offset="1.5" />
@@ -133,7 +134,7 @@
 
                 <Grid x:Name="ContentGrid"
                       MinHeight="16"
-                      VerticalAlignment="{TemplateBinding VerticalContentAlignment}">
+                      VerticalAlignment="Stretch">
                   <Grid.ColumnDefinitions>
                     <ColumnDefinition Width="Auto" />
                     <ColumnDefinition Width="Auto" />
@@ -156,7 +157,7 @@
                   <ScrollViewer x:Name="PART_ContentHost"
                                 Grid.Column="2"
                                 HorizontalAlignment="Stretch"
-                                VerticalAlignment="Center"
+                                VerticalAlignment="Stretch"
                                 HorizontalContentAlignment="{TemplateBinding HorizontalContentAlignment}"
                                 VerticalContentAlignment="{TemplateBinding VerticalContentAlignment}"
                                 Panel.ZIndex="1"
@@ -224,7 +225,7 @@
                   <TextBlock x:Name="PrefixTextBlock"
                              Grid.Column="1"
                              Margin="0,0,2,0"
-                             VerticalAlignment="Center"
+                             VerticalAlignment="{TemplateBinding VerticalContentAlignment, Converter={StaticResource PrefixSuffixTextVerticalAlignmentConverter}}"
                              FontSize="{TemplateBinding FontSize}"
                              Opacity="{TemplateBinding wpf:HintAssist.HintOpacity}"
                              Text="{TemplateBinding wpf:TextFieldAssist.PrefixText}">
@@ -242,7 +243,7 @@
                   <TextBlock x:Name="SuffixTextBlock"
                              Grid.Column="3"
                              Margin="2,0,0,0"
-                             VerticalAlignment="Center"
+                             VerticalAlignment="{TemplateBinding VerticalContentAlignment, Converter={StaticResource PrefixSuffixTextVerticalAlignmentConverter}}"
                              FontSize="{TemplateBinding FontSize}"
                              Opacity="{TemplateBinding wpf:HintAssist.HintOpacity}"
                              Text="{TemplateBinding wpf:TextFieldAssist.SuffixText}">
diff --git a/tests/MaterialDesignThemes.UITests/WPF/TextBoxes/TextBoxTests.cs b/tests/MaterialDesignThemes.UITests/WPF/TextBoxes/TextBoxTests.cs
index cb99989ac5..4b44c8d061 100644
--- a/tests/MaterialDesignThemes.UITests/WPF/TextBoxes/TextBoxTests.cs
+++ b/tests/MaterialDesignThemes.UITests/WPF/TextBoxes/TextBoxTests.cs
@@ -536,34 +536,6 @@ public async Task TextBox_WithHintAndValidationError_RespectsPadding(string styl
         recorder.Success();
     }
 
-    [Test]
-    [Arguments(VerticalAlignment.Stretch, VerticalAlignment.Stretch)]
-    [Arguments(VerticalAlignment.Top, VerticalAlignment.Top)]
-    [Arguments(VerticalAlignment.Bottom, VerticalAlignment.Bottom)]
-    [Arguments(VerticalAlignment.Center, VerticalAlignment.Center)]
-    [Description("Issue 3161")]
-    public async Task TextBox_MultiLineAndFixedHeight_RespectsVerticalContentAlignment(VerticalAlignment alignment, VerticalAlignment expectedFloatingHintAlignment)
-    {
-        await using var recorder = new TestRecorder(App);
-
-        var stackPanel = await LoadXaml<StackPanel>($$"""
-            <StackPanel>
-              <TextBox Style="{StaticResource MaterialDesignFilledTextBox}"
-                materialDesign:HintAssist.Hint="Hint text"
-                VerticalContentAlignment="{{alignment}}"
-                AcceptsReturn="True"
-                Height="200" />
-            </StackPanel>
-            """);
-
-        IVisualElement<TextBox> textBox = await stackPanel.GetElement<TextBox>("/TextBox");
-        IVisualElement<Grid> contentGrid = await textBox.GetElement<Grid>("ContentGrid");
-
-        await Assert.That(await contentGrid.GetVerticalAlignment()).IsEqualTo(expectedFloatingHintAlignment);
-
-        recorder.Success();
-    }
-
     [Test]
     [Description("Issue 3176")]
     public async Task ValidationErrorTemplate_WithChangingErrors_UpdatesValidation()