Avalonia/src/Avalonia.Themes.Fluent/TextBox.xaml

<Styles xmlns="https://github.com/avaloniaui" xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml">
  <Design.PreviewWith>
    <Border Padding="20">
      <TextBox Text="Sample"
               FontSize="20"
               Width="100"
               TextAlignment="Center"/>
    </Border>
  </Design.PreviewWith>
  
  <Styles.Resources>
    <Thickness x:Key="TextBoxTopHeaderMargin">0,0,0,4</Thickness>
  </Styles.Resources>
  <Style Selector="TextBox">
    <Setter Property="Foreground" Value="{DynamicResource TextControlForeground}" />
    <Setter Property="Background" Value="{DynamicResource TextControlBackground}" />
    <Setter Property="CaretBrush" Value="{DynamicResource TextControlForeground}" />
    <Setter Property="BorderBrush" Value="{DynamicResource TextControlBorderBrush}" />
    <Setter Property="SelectionBrush" Value="{DynamicResource TextControlSelectionHighlightColor}" />
    <Setter Property="BorderThickness" Value="{DynamicResource TextControlBorderThemeThickness}" />    
    <Setter Property="FontSize" Value="{DynamicResource ControlContentThemeFontSize}" />
    <Setter Property="MinHeight" Value="{DynamicResource TextControlThemeMinHeight}" />
    <Setter Property="MinWidth" Value="{DynamicResource TextControlThemeMinWidth}" />
    <Setter Property="Padding" Value="{DynamicResource TextControlThemePadding}" />
    <Setter Property="Template">
      <ControlTemplate>
        <DockPanel>

          <!-- TODO bind Content -> Header and ContentTemplate -> HeaderTemplate -->
          <ContentPresenter x:Name="HeaderContentPresenter"
                            DockPanel.Dock="Top"
                            TextBlock.FontWeight="Normal"
                            TextBlock.Foreground="{DynamicResource TextControlHeaderForeground}"
                            IsVisible="False"
                            Margin="{DynamicResource TextBoxTopHeaderMargin}" />

          <Panel>
            <Border
              Name="border"
              Background="{TemplateBinding Background}"
              BorderBrush="{TemplateBinding BorderBrush}"
              BorderThickness="{TemplateBinding BorderThickness}"
              CornerRadius="{DynamicResource ControlCornerRadius}"
              MinWidth="{TemplateBinding MinWidth}"
              MinHeight="{TemplateBinding MinHeight}">
            </Border>

            <Border
              Padding="{TemplateBinding Padding}"
              Margin="{TemplateBinding BorderThickness}">
              <DockPanel>
                <TextBlock Name="floatingWatermark"
                           Foreground="{DynamicResource SystemAccentColor}"
                           FontSize="{TemplateBinding FontSize}"
                           Text="{TemplateBinding Watermark}"
                           DockPanel.Dock="Top">
                  <TextBlock.IsVisible>
                      <MultiBinding Converter="{x:Static BoolConverters.And}">
                        <Binding RelativeSource="{RelativeSource TemplatedParent}"
                               Path="UseFloatingWatermark"/>
                        <Binding RelativeSource="{RelativeSource TemplatedParent}"
                               Path="Text"
                               Converter="{x:Static StringConverters.IsNotNullOrEmpty}"/>
                      </MultiBinding>
                  </TextBlock.IsVisible>
                </TextBlock>

                <DataValidationErrors>
                  <ScrollViewer HorizontalScrollBarVisibility="{TemplateBinding (ScrollViewer.HorizontalScrollBarVisibility)}"
                                VerticalScrollBarVisibility="{TemplateBinding (ScrollViewer.VerticalScrollBarVisibility)}">

                    <Panel>
                      <TextBlock Name="watermark"
                               Opacity="0.5"
                               Text="{TemplateBinding Watermark}"
                               TextAlignment="{TemplateBinding TextAlignment}"
                               TextWrapping="{TemplateBinding TextWrapping}"
                               IsVisible="{TemplateBinding Text, Converter={x:Static StringConverters.IsNullOrEmpty}}"
                               HorizontalAlignment="{TemplateBinding HorizontalContentAlignment}" 
                               VerticalAlignment="{TemplateBinding VerticalContentAlignment}"/>
                      <!-- TODO eliminate this margin... text layout issue? -->
                      <TextPresenter Name="PART_TextPresenter"
                                   Margin="0 1 0 0"
                                   Text="{TemplateBinding Text, Mode=TwoWay}"
                                   CaretIndex="{TemplateBinding CaretIndex}"
                                   SelectionStart="{TemplateBinding SelectionStart}"
                                   SelectionEnd="{TemplateBinding SelectionEnd}"
                                   TextAlignment="{TemplateBinding TextAlignment}"
                                   TextWrapping="{TemplateBinding TextWrapping}"
                                   PasswordChar="{TemplateBinding PasswordChar}"
                                   SelectionBrush="{TemplateBinding SelectionBrush}"
                                   SelectionForegroundBrush="{TemplateBinding SelectionForegroundBrush}"
                                   CaretBrush="{TemplateBinding CaretBrush}"
                                   HorizontalAlignment="{TemplateBinding HorizontalContentAlignment}" 
                                   VerticalAlignment="{TemplateBinding VerticalContentAlignment}"/> 
                    </Panel>
                  </ScrollViewer>
                </DataValidationErrors>
              </DockPanel>
            </Border>
          </Panel>
        </DockPanel>
      </ControlTemplate>
    </Setter>
  </Style>

  <!-- Disabled State -->
  <Style Selector="TextBox:disabled">
    <Setter Property="Foreground" Value="{DynamicResource TextControlForegroundDisabled}" />
  </Style>

  <Style Selector="TextBox:disabled /template/ Border#border">
    <Setter Property="Background" Value="{DynamicResource TextControlBackgroundDisabled}" />
    <Setter Property="BorderBrush" Value="{DynamicResource TextControlBorderBrushDisabled}" />
  </Style>

  <Style Selector="TextBox:disabled /template/ TextBlock#watermark, TextBox:disabled /template/ TextBlock#floatingWatermark">
    <Setter Property="Foreground" Value="{DynamicResource TextControlPlaceholderForegroundDisabled}" />
  </Style>

  <!-- PointerOver State-->
  <Style Selector="TextBox:disabled">
    <Setter Property="Foreground" Value="{DynamicResource TextControlForegroundPointerOver}" />
  </Style>

  <Style Selector="TextBox:pointerover /template/ Border#border">
    <Setter Property="BorderBrush" Value="{DynamicResource TextControlBorderBrushPointerOver}"/>
    <Setter Property="Background" Value="{DynamicResource TextControlBackgroundPointerOver}" />
  </Style>

  <Style Selector="TextBox:pointerover /template/ TextBlock#watermark, TextBox:pointerover /template/ TextBlock#floatingWatermark">
    <Setter Property="Foreground" Value="{DynamicResource TextControlPlaceholderForegroundPointerOver}" />
  </Style>

  <!-- Focused State -->
  <Style Selector="TextBox:focus">
    <Setter Property="Foreground" Value="{DynamicResource TextControlForegroundFocused}" />
  </Style>

  <Style Selector="TextBox:focus /template/ TextBlock#watermark, TextBox:focus /template/ TextBlock#floatingWatermark">
    <Setter Property="Foreground" Value="{DynamicResource TextControlPlaceholderForegroundFocused}" />
  </Style>

  <Style Selector="TextBox:focus /template/ Border#border">
    <Setter Property="Background" Value="{DynamicResource TextControlBackgroundFocused}"/>
    <Setter Property="BorderBrush" Value="{DynamicResource TextControlBorderBrushFocused}"/>
    <Setter Property="BorderThickness" Value="{DynamicResource TextControlBorderThemeThicknessFocused}" />
  </Style>


  <Style Selector="TextBox:error /template/ Border#border">
    <Setter Property="BorderBrush" Value="{DynamicResource SystemControlErrorTextForegroundBrush}"/>
  </Style>

  <Style Selector="TextBox /template/ DockPanel">
    <Setter Property="Cursor" Value="IBeam" />
  </Style>

</Styles>