chore: add avalonia DataValidationErrors demo.

src/Avalonia/HandyControlDemo_Avalonia/App.axaml.cs

@@ -1,4 +1,5 @@
 using System.Globalization;
+using System.Linq;
 using Avalonia;
 using Avalonia.Controls.ApplicationLifetimes;
 using Avalonia.Data.Core.Plugins;
@@ -17,7 +18,7 @@ public class App : Application
     public override void OnFrameworkInitializationCompleted()
     {
         Properties.Langs.Lang.Culture = new CultureInfo("en");
-        BindingPlugins.DataValidators.RemoveAt(0);
+        RemoveDefaultDataValidator();
 
         if (ApplicationLifetime is IClassicDesktopStyleApplicationLifetime desktop)
         {
@@ -26,4 +27,17 @@ public class App : Application
 
         base.OnFrameworkInitializationCompleted();
     }
+
+    private static void RemoveDefaultDataValidator()
+    {
+        // Get an array of plugins to remove
+        var dataValidationPluginsToRemove =
+            BindingPlugins.DataValidators.OfType<DataAnnotationsValidationPlugin>().ToArray();
+
+        // remove each entry found
+        foreach (var plugin in dataValidationPluginsToRemove)
+        {
+            BindingPlugins.DataValidators.Remove(plugin);
+        }
+    }
 }

src/Avalonia/HandyControlDemo_Avalonia/UserControl/Styles/TextBoxDemo.axaml

@@ -1,12 +1,9 @@
 <UserControl xmlns="https://github.com/avaloniaui"
              xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
-             xmlns:d="http://schemas.microsoft.com/expression/blend/2008"
-             xmlns:mc="http://schemas.openxmlformats.org/markup-compatibility/2006"
              xmlns:hc="https://handyorg.github.io/handycontrol"
-             mc:Ignorable="d"
+             xmlns:vm="clr-namespace:HandyControlDemo.ViewModel"
-             d:DesignWidth="800"
+             x:Class="HandyControlDemo.UserControl.TextBoxDemo"
-             d:DesignHeight="450"
+             DataContext="{Binding InputElementDemo, Source={x:Static vm:ViewModelLocator.Instance}}">
-             x:Class="HandyControlDemo.UserControl.TextBoxDemo">
     <ScrollViewer>
         <hc:UniformSpacingPanel Spacing="32"
                                 Margin="32"
@@ -32,6 +29,7 @@
                          Text="This is the content"
                          IsEnabled="False" />
                 <TextBox Watermark="please enter email"
+                         Text="{Binding Email1, UpdateSourceTrigger=PropertyChanged}"
                          hc:TitleElement.Title="This item must be filled in"
                          Theme="{StaticResource TextBoxExtend}"
                          hc:InfoElement.Necessary="True"
@@ -44,6 +42,7 @@
                          Margin="0,32,0,0"
                          Text="This is the content" />
                 <TextBox Width="380"
+                         Text="{Binding Text1, UpdateSourceTrigger=PropertyChanged}"
                          hc:TitleElement.TitleWidth="120"
                          Watermark="Please enter content"
                          hc:TitleElement.TitlePlacement="Left"
@@ -75,6 +74,7 @@
                          Text="This is the content"
                          IsEnabled="False" />
                 <TextBox Watermark="please enter email"
+                         Text="{Binding Email2, UpdateSourceTrigger=PropertyChanged}"
                          hc:TitleElement.Title="This item must be filled in"
                          Theme="{StaticResource TextBoxExtend.Small}"
                          hc:InfoElement.Necessary="True"
@@ -87,6 +87,7 @@
                          Margin="0,32,0,0"
                          Text="This is the content" />
                 <TextBox Width="380"
+                         Text="{Binding Text2, UpdateSourceTrigger=PropertyChanged}"
                          hc:TitleElement.TitleWidth="120"
                          Watermark="Please enter content"
                          hc:TitleElement.TitlePlacement="Left"

src/Avalonia/HandyControlDemo_Avalonia/ViewModel/Common/InputElementDemoViewModel.cs

@@ -0,0 +1,19 @@
+using System.ComponentModel.DataAnnotations;
+using CommunityToolkit.Mvvm.ComponentModel;
+
+namespace HandyControlDemo.ViewModel;
+
+public partial class InputElementDemoViewModel : ObservableValidator
+{
+    [Required] [EmailAddress] [ObservableProperty] [NotifyDataErrorInfo]
+    private string? _email1;
+
+    [Required] [EmailAddress] [ObservableProperty] [NotifyDataErrorInfo]
+    private string? _email2;
+
+    [Required] [ObservableProperty] [NotifyDataErrorInfo]
+    private string? _text1;
+
+    [Required] [ObservableProperty] [NotifyDataErrorInfo]
+    private string? _text2;
+}

src/Avalonia/HandyControlDemo_Avalonia/ViewModel/DemoViewModelBase`1.cs

@@ -3,13 +3,7 @@ using CommunityToolkit.Mvvm.ComponentModel;
 
 namespace HandyControlDemo.ViewModel;
 
-public class DemoViewModelBase<T> : ObservableObject
+public partial class DemoViewModelBase<T> : ObservableObject
 {
-    private IList<T> _dataList = [];
+    [ObservableProperty] private IList<T> _dataList = [];
-
-    public IList<T> DataList
-    {
-        get => _dataList;
-        set => SetProperty(ref _dataList, value);
-    }
 }

src/Avalonia/HandyControlDemo_Avalonia/ViewModel/ViewModelLocator.cs

@@ -19,9 +19,12 @@ public class ViewModelLocator
 
         services.AddSingleton<DataService>();
         services.AddTransient<MainViewModel>();
+        services.AddTransient<InputElementDemoViewModel>();
 
         _serviceProvider = services.BuildServiceProvider();
     }
 
     public MainViewModel Main => _serviceProvider.GetService<MainViewModel>()!;
+
+    public InputElementDemoViewModel InputElementDemo => _serviceProvider.GetService<InputElementDemoViewModel>()!;
 }

src/Avalonia/HandyControl_Avalonia/Themes/Styles/DataValidationErrors.axaml

@@ -0,0 +1,50 @@
+<ResourceDictionary xmlns="https://github.com/avaloniaui"
+                    xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml">
+    <ControlTheme x:Key="{x:Type DataValidationErrors}"
+                  TargetType="DataValidationErrors">
+        <Setter Property="Template">
+            <ControlTemplate>
+                <DockPanel LastChildFill="True">
+                    <ContentControl x:DataType="DataValidationErrors"
+                                    Content="{Binding (DataValidationErrors.Errors)}"
+                                    ContentTemplate="{TemplateBinding ErrorTemplate}"
+                                    DataContext="{TemplateBinding Owner}"
+                                    DockPanel.Dock="Right"
+                                    IsVisible="{Binding (DataValidationErrors.HasErrors)}" />
+                    <ContentPresenter Name="PART_ContentPresenter"
+                                      Padding="{TemplateBinding Padding}"
+                                      Background="{TemplateBinding Background}"
+                                      BorderBrush="{TemplateBinding BorderBrush}"
+                                      BorderThickness="{TemplateBinding BorderThickness}"
+                                      Content="{TemplateBinding Content}"
+                                      ContentTemplate="{TemplateBinding ContentTemplate}"
+                                      CornerRadius="{TemplateBinding CornerRadius}" />
+                </DockPanel>
+            </ControlTemplate>
+        </Setter>
+        <Setter Property="ErrorTemplate">
+            <DataTemplate>
+                <Canvas Width="16"
+                        Height="16"
+                        Margin="4,0,1,0"
+                        Background="Transparent">
+                    <Canvas.Styles>
+                        <Style Selector="ToolTip">
+                            <Setter Property="BorderBrush"
+                                    Value="{DynamicResource DangerBrush}" />
+                        </Style>
+                    </Canvas.Styles>
+                    <ToolTip.Tip>
+                        <ItemsControl x:DataType="DataValidationErrors"
+                                      ItemsSource="{Binding}" />
+                    </ToolTip.Tip>
+                    <Path Data="{StaticResource WarningGeometry}"
+                          Width="16"
+                          Height="16"
+                          Fill="{DynamicResource DangerBrush}"
+                          Stretch="Uniform" />
+                </Canvas>
+            </DataTemplate>
+        </Setter>
+    </ControlTheme>
+</ResourceDictionary>

src/Avalonia/HandyControl_Avalonia/Themes/Styles/TextBox.axaml

@@ -97,6 +97,11 @@
             <Setter Property="BorderBrush"
                     Value="{DynamicResource PrimaryBrush}" />
         </Style>
+
+        <Style Selector="^:error /template/ Border#border">
+            <Setter Property="BorderBrush"
+                    Value="{DynamicResource DangerBrush}" />
+        </Style>
     </ControlTheme>
 
     <ControlTemplate x:Key="TextBoxExtendTopTemplate"
@@ -121,77 +126,78 @@
                            TextTrimming="CharacterEllipsis"
                            Text="{Binding Path=(hc:TitleElement.Title), RelativeSource={RelativeSource TemplatedParent}}" />
             </DockPanel>
-            <Grid Grid.Row="1"
+            <DataValidationErrors Grid.Row="1">
-                  ColumnDefinitions="*,Auto">
+                <Grid ColumnDefinitions="*,Auto">
-                <Border x:Name="border"
+                    <Border x:Name="border"
-                        Grid.ColumnSpan="2"
+                            Grid.ColumnSpan="2"
-                        CornerRadius="{Binding Path=(hc:BorderElement.CornerRadius), RelativeSource={RelativeSource TemplatedParent}}"
+                            CornerRadius="{Binding Path=(hc:BorderElement.CornerRadius), RelativeSource={RelativeSource TemplatedParent}}"
-                        BorderBrush="{TemplateBinding BorderBrush}"
+                            BorderBrush="{TemplateBinding BorderBrush}"
-                        BorderThickness="{TemplateBinding BorderThickness}"
+                            BorderThickness="{TemplateBinding BorderThickness}"
-                        Background="{TemplateBinding Background}" />
+                            Background="{TemplateBinding Background}" />
-                <TextBlock Grid.Column="0"
+                    <TextBlock Grid.Column="0"
-                           VerticalAlignment="{TemplateBinding VerticalContentAlignment}"
+                               VerticalAlignment="{TemplateBinding VerticalContentAlignment}"
-                           Margin="{TemplateBinding Padding}"
+                               Margin="{TemplateBinding Padding}"
-                           IsVisible="{TemplateBinding Text, Converter={x:Static StringConverters.IsNullOrEmpty}}"
+                               IsVisible="{TemplateBinding Text, Converter={x:Static StringConverters.IsNullOrEmpty}}"
-                           HorizontalAlignment="Stretch"
+                               HorizontalAlignment="Stretch"
-                           Theme="{StaticResource TextBlockDefaultThiLight}"
+                               Theme="{StaticResource TextBlockDefaultThiLight}"
-                           Text="{TemplateBinding Watermark}" />
+                               Text="{TemplateBinding Watermark}" />
-                <ScrollViewer Grid.Column="0"
+                    <ScrollViewer Grid.Column="0"
-                              Name="PART_ScrollViewer"
+                                  Name="PART_ScrollViewer"
-                              AllowAutoHide="{TemplateBinding (ScrollViewer.AllowAutoHide)}"
+                                  AllowAutoHide="{TemplateBinding (ScrollViewer.AllowAutoHide)}"
-                              BringIntoViewOnFocusChange="{TemplateBinding (ScrollViewer.BringIntoViewOnFocusChange)}"
+                                  BringIntoViewOnFocusChange="{TemplateBinding (ScrollViewer.BringIntoViewOnFocusChange)}"
-                              HorizontalScrollBarVisibility="{TemplateBinding (ScrollViewer.HorizontalScrollBarVisibility)}"
+                                  HorizontalScrollBarVisibility="{TemplateBinding (ScrollViewer.HorizontalScrollBarVisibility)}"
-                              IsScrollChainingEnabled="{TemplateBinding (ScrollViewer.IsScrollChainingEnabled)}"
+                                  IsScrollChainingEnabled="{TemplateBinding (ScrollViewer.IsScrollChainingEnabled)}"
-                              VerticalScrollBarVisibility="{TemplateBinding (ScrollViewer.VerticalScrollBarVisibility)}">
+                                  VerticalScrollBarVisibility="{TemplateBinding (ScrollViewer.VerticalScrollBarVisibility)}">
-                    <TextPresenter Name="PART_TextPresenter"
+                        <TextPresenter Name="PART_TextPresenter"
-                                   Margin="{TemplateBinding Padding}"
+                                       Margin="{TemplateBinding Padding}"
-                                   VerticalAlignment="{TemplateBinding VerticalContentAlignment}"
+                                       VerticalAlignment="{TemplateBinding VerticalContentAlignment}"
-                                   CaretBlinkInterval="{TemplateBinding CaretBlinkInterval}"
+                                       CaretBlinkInterval="{TemplateBinding CaretBlinkInterval}"
-                                   CaretBrush="{TemplateBinding CaretBrush}"
+                                       CaretBrush="{TemplateBinding CaretBrush}"
-                                   CaretIndex="{TemplateBinding CaretIndex}"
+                                       CaretIndex="{TemplateBinding CaretIndex}"
-                                   LineHeight="{TemplateBinding LineHeight}"
+                                       LineHeight="{TemplateBinding LineHeight}"
-                                   LetterSpacing="{TemplateBinding LetterSpacing}"
+                                       LetterSpacing="{TemplateBinding LetterSpacing}"
-                                   PasswordChar="{TemplateBinding PasswordChar}"
+                                       PasswordChar="{TemplateBinding PasswordChar}"
-                                   RevealPassword="{TemplateBinding RevealPassword}"
+                                       RevealPassword="{TemplateBinding RevealPassword}"
-                                   SelectionBrush="{TemplateBinding SelectionBrush}"
+                                       SelectionBrush="{TemplateBinding SelectionBrush}"
-                                   SelectionEnd="{TemplateBinding SelectionEnd}"
+                                       SelectionEnd="{TemplateBinding SelectionEnd}"
-                                   SelectionForegroundBrush="{TemplateBinding SelectionForegroundBrush}"
+                                       SelectionForegroundBrush="{TemplateBinding SelectionForegroundBrush}"
-                                   SelectionStart="{TemplateBinding SelectionStart}"
+                                       SelectionStart="{TemplateBinding SelectionStart}"
-                                   Text="{TemplateBinding Text,Mode=TwoWay}"
+                                       Text="{TemplateBinding Text,Mode=TwoWay}"
-                                   TextAlignment="{TemplateBinding TextAlignment}"
+                                       TextAlignment="{TemplateBinding TextAlignment}"
-                                   TextWrapping="{TemplateBinding TextWrapping}" />
+                                       TextWrapping="{TemplateBinding TextWrapping}" />
-                    <ScrollViewer.Styles>
+                        <ScrollViewer.Styles>
-                        <Style Selector="ScrollContentPresenter#PART_ContentPresenter">
+                            <Style Selector="ScrollContentPresenter#PART_ContentPresenter">
-                            <Setter Property="Cursor"
+                                <Setter Property="Cursor"
-                                    Value="IBeam" />
+                                        Value="IBeam" />
-                        </Style>
+                            </Style>
-                    </ScrollViewer.Styles>
+                        </ScrollViewer.Styles>
-                </ScrollViewer>
+                    </ScrollViewer>
-                <Button HorizontalContentAlignment="Left"
+                    <Button HorizontalContentAlignment="Left"
-                        HorizontalAlignment="Stretch"
+                            HorizontalAlignment="Stretch"
-                        VerticalAlignment="Stretch"
+                            VerticalAlignment="Stretch"
-                        hc:IconElement.Width="14"
+                            hc:IconElement.Width="14"
-                        Command="{Binding $parent[TextBox].Clear}"
+                            Command="{Binding $parent[TextBox].Clear}"
-                        Name="ButtonClear"
+                            Name="ButtonClear"
-                        Focusable="False"
+                            Focusable="False"
-                        Grid.Column="1"
+                            Grid.Column="1"
-                        Theme="{StaticResource ButtonIcon}"
+                            Theme="{StaticResource ButtonIcon}"
-                        Padding="{Binding Padding, RelativeSource={RelativeSource TemplatedParent}, Converter={StaticResource ThicknessSplitConverter}, ConverterParameter='0,0,1,0'}"
+                            Padding="{Binding Padding, RelativeSource={RelativeSource TemplatedParent}, Converter={StaticResource ThicknessSplitConverter}, ConverterParameter='0,0,1,0'}"
-                        hc:IconElement.Geometry="{StaticResource DeleteFillCircleGeometry}"
+                            hc:IconElement.Geometry="{StaticResource DeleteFillCircleGeometry}"
-                        Foreground="{Binding BorderBrush,ElementName=border}">
+                            Foreground="{Binding BorderBrush,ElementName=border}">
-                    <Button.IsVisible>
+                        <Button.IsVisible>
-                        <MultiBinding Converter="{x:Static BoolConverters.And}">
+                            <MultiBinding Converter="{x:Static BoolConverters.And}">
-                            <Binding RelativeSource="{RelativeSource TemplatedParent}"
+                                <Binding RelativeSource="{RelativeSource TemplatedParent}"
-                                     Path="IsPointerOver" />
+                                         Path="IsPointerOver" />
-                            <Binding RelativeSource="{RelativeSource TemplatedParent}"
+                                <Binding RelativeSource="{RelativeSource TemplatedParent}"
-                                     Path="(hc:InfoElement.ShowClearButton)" />
+                                         Path="(hc:InfoElement.ShowClearButton)" />
-                            <Binding RelativeSource="{RelativeSource TemplatedParent}"
+                                <Binding RelativeSource="{RelativeSource TemplatedParent}"
-                                     Path="IsReadOnly"
+                                         Path="IsReadOnly"
-                                     Converter="{x:Static BoolConverters.Not}" />
+                                         Converter="{x:Static BoolConverters.Not}" />
-                        </MultiBinding>
+                            </MultiBinding>
-                    </Button.IsVisible>
+                        </Button.IsVisible>
-                </Button>
+                    </Button>
-            </Grid>
+                </Grid>
+            </DataValidationErrors>
         </Grid>
     </ControlTemplate>
 
@@ -218,77 +224,78 @@
                            TextTrimming="CharacterEllipsis"
                            Text="{Binding Path=(hc:TitleElement.Title), RelativeSource={RelativeSource TemplatedParent}}" />
             </DockPanel>
-            <Grid Grid.Column="1"
+            <DataValidationErrors Grid.Column="1">
-                  ColumnDefinitions="*,Auto">
+                <Grid ColumnDefinitions="*,Auto">
-                <Border x:Name="border"
+                    <Border x:Name="border"
-                        Grid.ColumnSpan="2"
+                            Grid.ColumnSpan="2"
-                        CornerRadius="{Binding Path=(hc:BorderElement.CornerRadius), RelativeSource={RelativeSource TemplatedParent}}"
+                            CornerRadius="{Binding Path=(hc:BorderElement.CornerRadius), RelativeSource={RelativeSource TemplatedParent}}"
-                        BorderBrush="{TemplateBinding BorderBrush}"
+                            BorderBrush="{TemplateBinding BorderBrush}"
-                        BorderThickness="{TemplateBinding BorderThickness}"
+                            BorderThickness="{TemplateBinding BorderThickness}"
-                        Background="{TemplateBinding Background}" />
+                            Background="{TemplateBinding Background}" />
-                <TextBlock Grid.Column="0"
+                    <TextBlock Grid.Column="0"
-                           VerticalAlignment="{TemplateBinding VerticalContentAlignment}"
+                               VerticalAlignment="{TemplateBinding VerticalContentAlignment}"
-                           Margin="{TemplateBinding Padding}"
+                               Margin="{TemplateBinding Padding}"
-                           IsVisible="{TemplateBinding Text, Converter={x:Static StringConverters.IsNullOrEmpty}}"
+                               IsVisible="{TemplateBinding Text, Converter={x:Static StringConverters.IsNullOrEmpty}}"
-                           HorizontalAlignment="Stretch"
+                               HorizontalAlignment="Stretch"
-                           Theme="{StaticResource TextBlockDefaultThiLight}"
+                               Theme="{StaticResource TextBlockDefaultThiLight}"
-                           Text="{TemplateBinding Watermark}" />
+                               Text="{TemplateBinding Watermark}" />
-                <ScrollViewer Grid.Column="0"
+                    <ScrollViewer Grid.Column="0"
-                              Name="PART_ScrollViewer"
+                                  Name="PART_ScrollViewer"
-                              AllowAutoHide="{TemplateBinding (ScrollViewer.AllowAutoHide)}"
+                                  AllowAutoHide="{TemplateBinding (ScrollViewer.AllowAutoHide)}"
-                              BringIntoViewOnFocusChange="{TemplateBinding (ScrollViewer.BringIntoViewOnFocusChange)}"
+                                  BringIntoViewOnFocusChange="{TemplateBinding (ScrollViewer.BringIntoViewOnFocusChange)}"
-                              HorizontalScrollBarVisibility="{TemplateBinding (ScrollViewer.HorizontalScrollBarVisibility)}"
+                                  HorizontalScrollBarVisibility="{TemplateBinding (ScrollViewer.HorizontalScrollBarVisibility)}"
-                              IsScrollChainingEnabled="{TemplateBinding (ScrollViewer.IsScrollChainingEnabled)}"
+                                  IsScrollChainingEnabled="{TemplateBinding (ScrollViewer.IsScrollChainingEnabled)}"
-                              VerticalScrollBarVisibility="{TemplateBinding (ScrollViewer.VerticalScrollBarVisibility)}">
+                                  VerticalScrollBarVisibility="{TemplateBinding (ScrollViewer.VerticalScrollBarVisibility)}">
-                    <TextPresenter Name="PART_TextPresenter"
+                        <TextPresenter Name="PART_TextPresenter"
-                                   Margin="{TemplateBinding Padding}"
+                                       Margin="{TemplateBinding Padding}"
-                                   VerticalAlignment="{TemplateBinding VerticalContentAlignment}"
+                                       VerticalAlignment="{TemplateBinding VerticalContentAlignment}"
-                                   CaretBlinkInterval="{TemplateBinding CaretBlinkInterval}"
+                                       CaretBlinkInterval="{TemplateBinding CaretBlinkInterval}"
-                                   CaretBrush="{TemplateBinding CaretBrush}"
+                                       CaretBrush="{TemplateBinding CaretBrush}"
-                                   CaretIndex="{TemplateBinding CaretIndex}"
+                                       CaretIndex="{TemplateBinding CaretIndex}"
-                                   LineHeight="{TemplateBinding LineHeight}"
+                                       LineHeight="{TemplateBinding LineHeight}"
-                                   LetterSpacing="{TemplateBinding LetterSpacing}"
+                                       LetterSpacing="{TemplateBinding LetterSpacing}"
-                                   PasswordChar="{TemplateBinding PasswordChar}"
+                                       PasswordChar="{TemplateBinding PasswordChar}"
-                                   RevealPassword="{TemplateBinding RevealPassword}"
+                                       RevealPassword="{TemplateBinding RevealPassword}"
-                                   SelectionBrush="{TemplateBinding SelectionBrush}"
+                                       SelectionBrush="{TemplateBinding SelectionBrush}"
-                                   SelectionEnd="{TemplateBinding SelectionEnd}"
+                                       SelectionEnd="{TemplateBinding SelectionEnd}"
-                                   SelectionForegroundBrush="{TemplateBinding SelectionForegroundBrush}"
+                                       SelectionForegroundBrush="{TemplateBinding SelectionForegroundBrush}"
-                                   SelectionStart="{TemplateBinding SelectionStart}"
+                                       SelectionStart="{TemplateBinding SelectionStart}"
-                                   Text="{TemplateBinding Text,Mode=TwoWay}"
+                                       Text="{TemplateBinding Text,Mode=TwoWay}"
-                                   TextAlignment="{TemplateBinding TextAlignment}"
+                                       TextAlignment="{TemplateBinding TextAlignment}"
-                                   TextWrapping="{TemplateBinding TextWrapping}" />
+                                       TextWrapping="{TemplateBinding TextWrapping}" />
-                    <ScrollViewer.Styles>
+                        <ScrollViewer.Styles>
-                        <Style Selector="ScrollContentPresenter#PART_ContentPresenter">
+                            <Style Selector="ScrollContentPresenter#PART_ContentPresenter">
-                            <Setter Property="Cursor"
+                                <Setter Property="Cursor"
-                                    Value="IBeam" />
+                                        Value="IBeam" />
-                        </Style>
+                            </Style>
-                    </ScrollViewer.Styles>
+                        </ScrollViewer.Styles>
-                </ScrollViewer>
+                    </ScrollViewer>
-                <Button HorizontalContentAlignment="Left"
+                    <Button HorizontalContentAlignment="Left"
-                        HorizontalAlignment="Stretch"
+                            HorizontalAlignment="Stretch"
-                        VerticalAlignment="Stretch"
+                            VerticalAlignment="Stretch"
-                        hc:IconElement.Width="14"
+                            hc:IconElement.Width="14"
-                        Command="{Binding $parent[TextBox].Clear}"
+                            Command="{Binding $parent[TextBox].Clear}"
-                        Name="ButtonClear"
+                            Name="ButtonClear"
-                        Focusable="False"
+                            Focusable="False"
-                        Grid.Column="1"
+                            Grid.Column="1"
-                        Theme="{StaticResource ButtonIcon}"
+                            Theme="{StaticResource ButtonIcon}"
-                        Padding="{Binding Padding, RelativeSource={RelativeSource TemplatedParent}, Converter={StaticResource ThicknessSplitConverter}, ConverterParameter='0,0,1,0'}"
+                            Padding="{Binding Padding, RelativeSource={RelativeSource TemplatedParent}, Converter={StaticResource ThicknessSplitConverter}, ConverterParameter='0,0,1,0'}"
-                        hc:IconElement.Geometry="{StaticResource DeleteFillCircleGeometry}"
+                            hc:IconElement.Geometry="{StaticResource DeleteFillCircleGeometry}"
-                        Foreground="{Binding BorderBrush,ElementName=border}">
+                            Foreground="{Binding BorderBrush,ElementName=border}">
-                    <Button.IsVisible>
+                        <Button.IsVisible>
-                        <MultiBinding Converter="{x:Static BoolConverters.And}">
+                            <MultiBinding Converter="{x:Static BoolConverters.And}">
-                            <Binding RelativeSource="{RelativeSource TemplatedParent}"
+                                <Binding RelativeSource="{RelativeSource TemplatedParent}"
-                                     Path="IsPointerOver" />
+                                         Path="IsPointerOver" />
-                            <Binding RelativeSource="{RelativeSource TemplatedParent}"
+                                <Binding RelativeSource="{RelativeSource TemplatedParent}"
-                                     Path="(hc:InfoElement.ShowClearButton)" />
+                                         Path="(hc:InfoElement.ShowClearButton)" />
-                            <Binding RelativeSource="{RelativeSource TemplatedParent}"
+                                <Binding RelativeSource="{RelativeSource TemplatedParent}"
-                                     Path="IsReadOnly"
+                                         Path="IsReadOnly"
-                                     Converter="{x:Static BoolConverters.Not}" />
+                                         Converter="{x:Static BoolConverters.Not}" />
-                        </MultiBinding>
+                            </MultiBinding>
-                    </Button.IsVisible>
+                        </Button.IsVisible>
-                </Button>
+                    </Button>
-            </Grid>
+                </Grid>
+            </DataValidationErrors>
         </Grid>
     </ControlTemplate>
 

src/Avalonia/HandyControl_Avalonia/Themes/Theme.axaml

@@ -15,6 +15,7 @@
                 <MergeResourceInclude Source="/Themes/Basic/Brushes.axaml" />
                 <MergeResourceInclude Source="/Themes/Basic/Converters.axaml" />
 
+                <MergeResourceInclude Source="/Themes/Styles/DataValidationErrors.axaml" />
                 <MergeResourceInclude Source="/Themes/Styles/TextBlock.axaml" />
                 <MergeResourceInclude Source="/Themes/Styles/ContentControl.axaml" />
                 <MergeResourceInclude Source="/Themes/Styles/UserControl.axaml" />
@@ -39,9 +40,4 @@
             </ResourceDictionary.MergedDictionaries>
         </ResourceDictionary>
     </Styles.Resources>
-
-    <Style Selector=":is(UserControl)">
-        <Setter Property="Theme"
-                Value="{DynamicResource {x:Type UserControl}}" />
-    </Style>
 </Styles>