FloatingTextBoxStyle

.xaml

<ResourceDictionary
    xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation" 
    xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml">

    <Style x:Key="FloatingHeaderTextBoxStyle" TargetType="TextBox">
        <Setter Property="MinWidth" Value="{ThemeResource TextControlThemeMinWidth}"/>
        <Setter Property="MinHeight" Value="{ThemeResource TextControlThemeMinHeight}"/>
        <Setter Property="Foreground" Value="{ThemeResource SystemControlForegroundBaseHighBrush}"/>
        <Setter Property="Background" Value="{ThemeResource SystemControlBackgroundAltHighBrush}"/>
        <Setter Property="BorderBrush" Value="{ThemeResource SystemControlForegroundChromeDisabledLowBrush}"/>
        <Setter Property="SelectionHighlightColor" Value="{ThemeResource SystemControlHighlightAccentBrush}"/>
        <Setter Property="BorderThickness" Value="{ThemeResource TextControlBorderThemeThickness}"/>
        <Setter Property="FontFamily" Value="{ThemeResource ContentControlThemeFontFamily}"/>
        <Setter Property="FontSize" Value="{ThemeResource ControlContentThemeFontSize}"/>
        <Setter Property="ScrollViewer.HorizontalScrollBarVisibility" Value="Hidden"/>
        <Setter Property="ScrollViewer.VerticalScrollBarVisibility" Value="Hidden"/>
        <Setter Property="ScrollViewer.IsDeferredScrollingEnabled" Value="False"/>
        <Setter Property="Padding" Value="{ThemeResource TextControlThemePadding}"/>
        <Setter Property="Template">
            <Setter.Value>
                <ControlTemplate TargetType="TextBox">
                    <Grid>
                        <Grid.Resources>
                            <Style x:Name="DeleteButtonStyle" TargetType="Button">
                                <Setter Property="Template">
                                    <Setter.Value>
                                        <ControlTemplate TargetType="Button">
                                            <Grid x:Name="ButtonLayoutGrid" BorderBrush="{ThemeResource TextBoxButtonBorderThemeBrush}" BorderThickness="{TemplateBinding BorderThickness}" Background="{ThemeResource TextBoxButtonBackgroundThemeBrush}">
                                                <VisualStateManager.VisualStateGroups>
                                                    <VisualStateGroup x:Name="CommonStates">
                                                        <VisualState x:Name="Normal"/>
                                                        <VisualState x:Name="PointerOver">
                                                            <Storyboard>
                                                                <ObjectAnimationUsingKeyFrames Storyboard.TargetProperty="Foreground" Storyboard.TargetName="GlyphElement">
                                                                    <DiscreteObjectKeyFrame KeyTime="0" Value="{ThemeResource SystemControlHighlightAccentBrush}"/>
                                                                </ObjectAnimationUsingKeyFrames>
                                                            </Storyboard>
                                                        </VisualState>
                                                        <VisualState x:Name="Pressed">
                                                            <Storyboard>
                                                                <ObjectAnimationUsingKeyFrames Storyboard.TargetProperty="Background" Storyboard.TargetName="ButtonLayoutGrid">
                                                                    <DiscreteObjectKeyFrame KeyTime="0" Value="{ThemeResource SystemControlHighlightAccentBrush}"/>
                                                                </ObjectAnimationUsingKeyFrames>
                                                                <ObjectAnimationUsingKeyFrames Storyboard.TargetProperty="Foreground" Storyboard.TargetName="GlyphElement">
                                                                    <DiscreteObjectKeyFrame KeyTime="0" Value="{ThemeResource SystemControlHighlightAltChromeWhiteBrush}"/>
                                                                </ObjectAnimationUsingKeyFrames>
                                                            </Storyboard>
                                                        </VisualState>
                                                        <VisualState x:Name="Disabled">
                                                            <Storyboard>
                                                                <DoubleAnimation Duration="0" To="0" Storyboard.TargetProperty="Opacity" Storyboard.TargetName="ButtonLayoutGrid"/>
                                                            </Storyboard>
                                                        </VisualState>
                                                    </VisualStateGroup>
                                                </VisualStateManager.VisualStateGroups>
                                                <TextBlock x:Name="GlyphElement" AutomationProperties.AccessibilityView="Raw" Foreground="{ThemeResource SystemControlForegroundChromeBlackMediumBrush}" FontStyle="Normal" FontSize="12" FontFamily="{ThemeResource SymbolThemeFontFamily}" HorizontalAlignment="Center" Text="&#xE10A;" VerticalAlignment="Center"/>
                                            </Grid>
                                        </ControlTemplate>
                                    </Setter.Value>
                                </Setter>
                            </Style>
                        </Grid.Resources>
                        <Grid.ColumnDefinitions>
                            <ColumnDefinition Width="*"/>
                            <ColumnDefinition Width="Auto"/>
                        </Grid.ColumnDefinitions>
                        <Grid.RowDefinitions>
                            <RowDefinition Height="Auto"/>
                            <RowDefinition Height="*"/>
                        </Grid.RowDefinitions>
                        <VisualStateManager.VisualStateGroups>
                            <VisualStateGroup x:Name="CommonStates">
                                <VisualStateGroup.Transitions>
                                    <VisualTransition From="Focused"
                                                          GeneratedDuration="0:0:0.1"
                                                          />
                                </VisualStateGroup.Transitions>
                                <VisualState x:Name="Disabled">
                                    <Storyboard>
                                        <ObjectAnimationUsingKeyFrames Storyboard.TargetProperty="Foreground" Storyboard.TargetName="HeaderContentPresenter">
                                            <DiscreteObjectKeyFrame KeyTime="0" Value="{ThemeResource SystemControlDisabledBaseLowBrush}"/>
                                        </ObjectAnimationUsingKeyFrames>
                                        <ObjectAnimationUsingKeyFrames Storyboard.TargetProperty="Background" Storyboard.TargetName="BackgroundElement">
                                            <DiscreteObjectKeyFrame KeyTime="0" Value="{ThemeResource SystemControlDisabledTransparentBrush}"/>
                                        </ObjectAnimationUsingKeyFrames>
                                        <ObjectAnimationUsingKeyFrames Storyboard.TargetProperty="Background" Storyboard.TargetName="BorderElement">
                                            <DiscreteObjectKeyFrame KeyTime="0" Value="{ThemeResource SystemControlBackgroundBaseLowBrush}"/>
                                        </ObjectAnimationUsingKeyFrames>
                                        <ObjectAnimationUsingKeyFrames Storyboard.TargetProperty="BorderBrush" Storyboard.TargetName="BorderElement">
                                            <DiscreteObjectKeyFrame KeyTime="0" Value="{ThemeResource SystemControlDisabledBaseLowBrush}"/>
                                        </ObjectAnimationUsingKeyFrames>
                                        <ObjectAnimationUsingKeyFrames Storyboard.TargetProperty="Foreground" Storyboard.TargetName="ContentElement">
                                            <DiscreteObjectKeyFrame KeyTime="0" Value="{ThemeResource SystemControlDisabledChromeDisabledLowBrush}"/>
                                        </ObjectAnimationUsingKeyFrames>
                                        <ObjectAnimationUsingKeyFrames Storyboard.TargetProperty="Foreground" Storyboard.TargetName="PlaceholderTextContentPresenter">
                                            <DiscreteObjectKeyFrame KeyTime="0" Value="{ThemeResource SystemControlDisabledChromeDisabledLowBrush}"/>
                                        </ObjectAnimationUsingKeyFrames>
                                    </Storyboard>
                                </VisualState>
                                <VisualState x:Name="Normal"/>
                                <VisualState x:Name="PointerOver">
                                    <Storyboard>
                                        <ObjectAnimationUsingKeyFrames Storyboard.TargetProperty="BorderBrush" Storyboard.TargetName="BorderElement">
                                            <DiscreteObjectKeyFrame KeyTime="0" Value="{ThemeResource SystemControlHighlightChromeAltLowBrush}"/>
                                        </ObjectAnimationUsingKeyFrames>
                                        <ObjectAnimationUsingKeyFrames Storyboard.TargetProperty="Opacity" Storyboard.TargetName="BackgroundElement">
                                            <DiscreteObjectKeyFrame KeyTime="0" Value="{ThemeResource TextControlBackgroundHoverOpacity}"/>
                                        </ObjectAnimationUsingKeyFrames>
                                    </Storyboard>
                                </VisualState>
                                <VisualState x:Name="Focused">
                                    <Storyboard>
                                        <ObjectAnimationUsingKeyFrames Storyboard.TargetProperty="Foreground" Storyboard.TargetName="PlaceholderTextContentPresenter">
                                            <DiscreteObjectKeyFrame KeyTime="0" Value="{ThemeResource SystemControlPageTextChromeBlackMediumLowBrush}"/>
                                        </ObjectAnimationUsingKeyFrames>
                                        <ObjectAnimationUsingKeyFrames Storyboard.TargetProperty="Background" Storyboard.TargetName="BackgroundElement">
                                            <DiscreteObjectKeyFrame KeyTime="0" Value="{ThemeResource SystemControlBackgroundChromeWhiteBrush}"/>
                                        </ObjectAnimationUsingKeyFrames>
                                        <ObjectAnimationUsingKeyFrames Storyboard.TargetProperty="Opacity" Storyboard.TargetName="BackgroundElement">
                                            <DiscreteObjectKeyFrame KeyTime="0" Value="{ThemeResource TextControlBackgroundFocusedOpacity}"/>
                                        </ObjectAnimationUsingKeyFrames>
                                        <ObjectAnimationUsingKeyFrames Storyboard.TargetProperty="BorderBrush" Storyboard.TargetName="BorderElement">
                                            <DiscreteObjectKeyFrame KeyTime="0" Value="{ThemeResource SystemControlHighlightAccentBrush}"/>
                                        </ObjectAnimationUsingKeyFrames>
                                        <ObjectAnimationUsingKeyFrames Storyboard.TargetProperty="Foreground" Storyboard.TargetName="ContentElement">
                                            <DiscreteObjectKeyFrame KeyTime="0" Value="{ThemeResource SystemControlForegroundChromeBlackHighBrush}"/>
                                        </ObjectAnimationUsingKeyFrames>

                                        <DoubleAnimation Storyboard.TargetName="HeaderContentPresenter"
                                                             Storyboard.TargetProperty="Opacity"
                                                             To="1" Duration="0:0:0.25"
                                                             />
                                        <DoubleAnimation Storyboard.TargetName="HeaderContentPresenter"
                                                             Storyboard.TargetProperty="(UIElement.RenderTransform).(TranslateTransform.Y)"
                                                             To="0" Duration="0:0:0.25"
                                                             >
                                            <DoubleAnimation.EasingFunction>
                                                <SineEase EasingMode="EaseOut" />
                                            </DoubleAnimation.EasingFunction>
                                        </DoubleAnimation>
                                    </Storyboard>
                                </VisualState>
                            </VisualStateGroup>
                            <VisualStateGroup x:Name="ButtonStates">
                                <VisualState x:Name="ButtonVisible">
                                    <Storyboard>
                                        <ObjectAnimationUsingKeyFrames Storyboard.TargetProperty="Visibility" Storyboard.TargetName="DeleteButton">
                                            <DiscreteObjectKeyFrame KeyTime="0">
                                                <DiscreteObjectKeyFrame.Value>
                                                    <Visibility>Visible</Visibility>
                                                </DiscreteObjectKeyFrame.Value>
                                            </DiscreteObjectKeyFrame>
                                        </ObjectAnimationUsingKeyFrames>
                                    </Storyboard>
                                </VisualState>
                                <VisualState x:Name="ButtonCollapsed"/>
                            </VisualStateGroup>
                        </VisualStateManager.VisualStateGroups>
                        <Border x:Name="BackgroundElement" Background="{TemplateBinding Background}" Grid.ColumnSpan="2" Margin="{TemplateBinding BorderThickness}" Opacity="{ThemeResource TextControlBackgroundRestOpacity}" Grid.Row="1" Grid.RowSpan="1"/>
                        <Border x:Name="BorderElement" BorderBrush="{TemplateBinding BorderBrush}" BorderThickness="{TemplateBinding BorderThickness}" Grid.ColumnSpan="2" Grid.Row="1" Grid.RowSpan="1"/>
                        <ContentPresenter x:Name="HeaderContentPresenter" Grid.ColumnSpan="2" ContentTemplate="{TemplateBinding HeaderTemplate}" Content="{TemplateBinding Header}" Foreground="{ThemeResource SystemControlForegroundBaseHighBrush}" FontWeight="Normal" Margin="0,0,0,8" Grid.Row="0"
                                              Opacity="0"
                                              >
                            <ContentPresenter.RenderTransform>
                                <TranslateTransform Y="25" />
                            </ContentPresenter.RenderTransform>
                        </ContentPresenter>
                        <ScrollViewer x:Name="ContentElement" AutomationProperties.AccessibilityView="Raw" HorizontalScrollMode="{TemplateBinding ScrollViewer.HorizontalScrollMode}" HorizontalScrollBarVisibility="{TemplateBinding ScrollViewer.HorizontalScrollBarVisibility}" IsTabStop="False" IsHorizontalRailEnabled="{TemplateBinding ScrollViewer.IsHorizontalRailEnabled}" IsVerticalRailEnabled="{TemplateBinding ScrollViewer.IsVerticalRailEnabled}" IsDeferredScrollingEnabled="{TemplateBinding ScrollViewer.IsDeferredScrollingEnabled}" Margin="{TemplateBinding BorderThickness}" Padding="{TemplateBinding Padding}" Grid.Row="1" VerticalScrollBarVisibility="{TemplateBinding ScrollViewer.VerticalScrollBarVisibility}" VerticalScrollMode="{TemplateBinding ScrollViewer.VerticalScrollMode}" ZoomMode="Disabled"/>
                        <ContentControl x:Name="PlaceholderTextContentPresenter" Grid.ColumnSpan="2" Content="{TemplateBinding PlaceholderText}" Foreground="{ThemeResource SystemControlPageTextBaseMediumBrush}" IsHitTestVisible="False" IsTabStop="False" Margin="{TemplateBinding BorderThickness}" Padding="{TemplateBinding Padding}" Grid.Row="1"/>
                        <Button x:Name="DeleteButton" BorderThickness="{TemplateBinding BorderThickness}" Grid.Column="1" FontSize="{TemplateBinding FontSize}" IsTabStop="False" Margin="{ThemeResource HelperButtonThemePadding}" MinWidth="34" Grid.Row="1" Style="{StaticResource DeleteButtonStyle}" Visibility="Collapsed" VerticalAlignment="Stretch"/>
                    </Grid>
                </ControlTemplate>
            </Setter.Value>
        </Setter>
    </Style>

</ResourceDictionary>