Avalonia/samples/ControlCatalog/Pages/TextBoxPage.xaml

<UserControl xmlns="https://github.com/avaloniaui"
  xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml" x:Class="ControlCatalog.Pages.TextBoxPage">
  <StackPanel Orientation="Vertical" Spacing="4">
    <TextBlock Classes="h1">TextBox</TextBlock>
    <TextBlock Classes="h2">A control into which the user can input text</TextBlock>

    <StackPanel Orientation="Horizontal" Margin="0,16,0,0" HorizontalAlignment="Center" Spacing="16">
      <StackPanel Orientation="Vertical" Spacing="8">
        <TextBox Text="Lorem ipsum dolor sit amet, consectetur adipiscing elit." Width="200" />
        <TextBox Watermark="ReadOnly" IsReadOnly="True" Text="This is read only"/>
        <TextBox Width="200" Watermark="Watermark" />
        <TextBox Width="200" Watermark="Floating Watermark" UseFloatingWatermark="True" Text="Lorem ipsum dolor sit amet, consectetur adipiscing elit."/>

        <TextBox Width="200" Watermark="Password Box" UseFloatingWatermark="True" PasswordChar="*" Text="Password" />
        <TextBox Width="200" Text="Left aligned text" TextAlignment="Left" />
        <TextBox Width="200" Text="Center aligned text" TextAlignment="Center" />
        <TextBox Width="200" Text="Right aligned text" TextAlignment="Right" />
        <TextBox Width="200" Text="Custom selection brush" SelectionStart="5" SelectionEnd="22" SelectionBrush="Green" SelectionForegroundBrush="Yellow"/>
        <TextBox Width="200" Text="Custom caret brush" CaretBrush="DarkOrange"/>
      </StackPanel>

      <StackPanel Orientation="Vertical" Spacing="8">
        <TextBox AcceptsReturn="True" TextWrapping="Wrap" Width="200" Height="125" Text="Multiline TextBox with TextWrapping.&#xD;&#xD;Lorem ipsum dolor sit amet, consectetur adipiscing elit. Vivamus magna. Cras in mi at felis aliquet congue. Ut a est eget ligula molestie gravida. Curabitur massa. Donec eleifend, libero at sagittis mollis, tellus est malesuada tellus, at luctus turpis elit sit amet quam. Vivamus pretium ornare est." />
        <TextBox AcceptsReturn="True" Width="200" Height="125" Text="Multiline TextBox with no TextWrapping.&#xD;&#xD;Lorem ipsum dolor sit amet, consectetur adipiscing elit. Vivamus magna. Cras in mi at felis aliquet congue. Ut a est eget ligula molestie gravida. Curabitur massa. Donec eleifend, libero at sagittis mollis, tellus est malesuada tellus, at luctus turpis elit sit amet quam. Vivamus pretium ornare est." />
      </StackPanel>
      <StackPanel Orientation="Vertical" Spacing="8">
        <TextBlock Classes="h2">resm fonts</TextBlock>
        <TextBox Width="200" Text="Custom font regular" FontWeight="Normal" FontStyle="Normal" FontFamily="resm:ControlCatalog.Assets.Fonts?assembly=ControlCatalog#Source Sans Pro"/>
        <TextBox Width="200" Text="Custom font bold" FontWeight="Bold" FontStyle="Normal" FontFamily="resm:ControlCatalog.Assets.Fonts?assembly=ControlCatalog#Source Sans Pro"/>
        <TextBox Width="200" Text="Custom font italic" FontWeight="Normal" FontStyle="Italic" FontFamily="resm:ControlCatalog.Assets.Fonts.SourceSansPro-Italic.ttf?assembly=ControlCatalog#Source Sans Pro"/>
        <TextBox Width="200" Text="Custom font italic bold" FontWeight="Bold" FontStyle="Italic" FontFamily="resm:ControlCatalog.Assets.Fonts.SourceSansPro-*.ttf?assembly=ControlCatalog#Source Sans Pro"/>
      </StackPanel>

      <StackPanel Orientation="Vertical" Spacing="8">
        <TextBlock Classes="h2">res fonts</TextBlock>
        <TextBox Width="200" Text="Custom font regular" FontWeight="Normal" FontStyle="Normal" FontFamily="avares://ControlCatalog/Assets/Fonts#Source Sans Pro"/>
        <TextBox Width="200" Text="Custom font bold" FontWeight="Bold" FontStyle="Normal" FontFamily="avares://ControlCatalog/Assets/Fonts#Source Sans Pro"/>
        <TextBox Width="200" Text="Custom font italic" FontWeight="Normal" FontStyle="Italic" FontFamily="/Assets/Fonts/SourceSansPro-Italic.ttf#Source Sans Pro"/>
        <TextBox Width="200" Text="Custom font italic bold" FontWeight="Bold" FontStyle="Italic" FontFamily="/Assets/Fonts/SourceSansPro-*.ttf#Source Sans Pro"/>
      </StackPanel>


      <StackPanel Orientation="Vertical" Spacing="8">
        <StackPanel.Styles>
          <Style Selector="TextBox">
            <Setter Property="InnerRightContent">
              <Template>
                <Button Content="Clear" />
              </Template>
            </Setter>

          </Style>
        </StackPanel.Styles>

        <TextBlock Classes="h2">Test</TextBlock>
        <TextBox Width="200" Text="Custom font regular" FontWeight="Normal" FontStyle="Normal" FontFamily="avares://ControlCatalog/Assets/Fonts#Source Sans Pro"/>
      </StackPanel>

    </StackPanel>
  </StackPanel>
</UserControl>