Outer glow rounded corners TextBox

Question

I'm trying to understand some of the basic limitations of XAML for UWP and how to bend the styling of the XAML controls.

I decided to see if its possible to create a textbox control with rounded corners with an outer glow border effect.

I haven't tried anything since all the places I end up at when searching for a solution appears to only apply to the WPF platform.

How would one create a textbox with rounded corners and an outer glow effect? Is their any further read of how to create truly custom controls?

Example:

Answer 1

To do it you will have to edit a Style of your TextBox. The radius is quite easy - just change the CornerRadius of BorderElement, the shadow is more complicated. You can simulate it with couple of Borders/Rectangles like in this answer, however it's quite difficult to obtain nice effect. Much better you can achieve with UWPCommunityToolkit's DropShadowPanel. The sample style I've created can look like this:

<Page.Resources>
    <Style x:Key="MyTextBoxStyle" TargetType="TextBox">
        <Setter Property="MinWidth" Value="{ThemeResource TextControlThemeMinWidth}"/>
        <Setter Property="MinHeight" Value="{ThemeResource TextControlThemeMinHeight}"/>
        <Setter Property="Foreground" Value="{ThemeResource TextControlForeground}"/>
        <Setter Property="Background" Value="{ThemeResource TextControlBackground}"/>
        <Setter Property="BorderBrush" Value="{ThemeResource TextControlBorderBrush}"/>
        <Setter Property="SelectionHighlightColor" Value="{ThemeResource TextControlSelectionHighlightColor}"/>
        <Setter Property="BorderThickness" Value="{ThemeResource TextControlBorderThemeThickness}"/>
        <Setter Property="FontFamily" Value="{ThemeResource ContentControlThemeFontFamily}"/>
        <Setter Property="FontSize" Value="{ThemeResource ControlContentThemeFontSize}"/>
        <Setter Property="ScrollViewer.HorizontalScrollMode" Value="Auto"/>
        <Setter Property="ScrollViewer.VerticalScrollMode" Value="Auto"/>
        <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 TextControlButtonBorderBrush}" BorderThickness="{TemplateBinding BorderThickness}" Background="{ThemeResource TextControlButtonBackground}">
                                                <VisualStateManager.VisualStateGroups>
                                                    <VisualStateGroup x:Name="CommonStates">
                                                        <VisualState x:Name="Normal"/>
                                                        <VisualState x:Name="PointerOver">
                                                            <Storyboard>
                                                                <ObjectAnimationUsingKeyFrames Storyboard.TargetProperty="Background" Storyboard.TargetName="ButtonLayoutGrid">
                                                                    <DiscreteObjectKeyFrame KeyTime="0" Value="{ThemeResource TextControlButtonBackgroundPointerOver}"/>
                                                                </ObjectAnimationUsingKeyFrames>
                                                                <ObjectAnimationUsingKeyFrames Storyboard.TargetProperty="BorderBrush" Storyboard.TargetName="ButtonLayoutGrid">
                                                                    <DiscreteObjectKeyFrame KeyTime="0" Value="{ThemeResource TextControlButtonBorderBrushPointerOver}"/>
                                                                </ObjectAnimationUsingKeyFrames>
                                                                <ObjectAnimationUsingKeyFrames Storyboard.TargetProperty="Foreground" Storyboard.TargetName="GlyphElement">
                                                                    <DiscreteObjectKeyFrame KeyTime="0" Value="{ThemeResource TextControlButtonForegroundPointerOver}"/>
                                                                </ObjectAnimationUsingKeyFrames>
                                                            </Storyboard>
                                                        </VisualState>
                                                        <VisualState x:Name="Pressed">
                                                            <Storyboard>
                                                                <ObjectAnimationUsingKeyFrames Storyboard.TargetProperty="Background" Storyboard.TargetName="ButtonLayoutGrid">
                                                                    <DiscreteObjectKeyFrame KeyTime="0" Value="{ThemeResource TextControlButtonBackgroundPressed}"/>
                                                                </ObjectAnimationUsingKeyFrames>
                                                                <ObjectAnimationUsingKeyFrames Storyboard.TargetProperty="BorderBrush" Storyboard.TargetName="ButtonLayoutGrid">
                                                                    <DiscreteObjectKeyFrame KeyTime="0" Value="{ThemeResource TextControlButtonBorderBrushPressed}"/>
                                                                </ObjectAnimationUsingKeyFrames>
                                                                <ObjectAnimationUsingKeyFrames Storyboard.TargetProperty="Foreground" Storyboard.TargetName="GlyphElement">
                                                                    <DiscreteObjectKeyFrame KeyTime="0" Value="{ThemeResource TextControlButtonForegroundPressed}"/>
                                                                </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 TextControlButtonForeground}" 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">
                                <VisualState x:Name="Disabled">
                                    <Storyboard>
                                        <ObjectAnimationUsingKeyFrames Storyboard.TargetProperty="Foreground" Storyboard.TargetName="HeaderContentPresenter">
                                            <DiscreteObjectKeyFrame KeyTime="0" Value="{ThemeResource TextControlHeaderForegroundDisabled}"/>
                                        </ObjectAnimationUsingKeyFrames>
                                        <ObjectAnimationUsingKeyFrames Storyboard.TargetProperty="Background" Storyboard.TargetName="BorderElement">
                                            <DiscreteObjectKeyFrame KeyTime="0" Value="{ThemeResource TextControlBackgroundDisabled}"/>
                                        </ObjectAnimationUsingKeyFrames>
                                        <ObjectAnimationUsingKeyFrames Storyboard.TargetProperty="BorderBrush" Storyboard.TargetName="BorderElement">
                                            <DiscreteObjectKeyFrame KeyTime="0" Value="{ThemeResource TextControlBorderBrushDisabled}"/>
                                        </ObjectAnimationUsingKeyFrames>
                                        <ObjectAnimationUsingKeyFrames Storyboard.TargetProperty="Foreground" Storyboard.TargetName="ContentElement">
                                            <DiscreteObjectKeyFrame KeyTime="0" Value="{ThemeResource TextControlForegroundDisabled}"/>
                                        </ObjectAnimationUsingKeyFrames>
                                        <ObjectAnimationUsingKeyFrames Storyboard.TargetProperty="Foreground" Storyboard.TargetName="PlaceholderTextContentPresenter">
                                            <DiscreteObjectKeyFrame KeyTime="0" Value="{ThemeResource TextControlPlaceholderForegroundDisabled}"/>
                                        </ObjectAnimationUsingKeyFrames>
                                    </Storyboard>
                                </VisualState>
                                <VisualState x:Name="Normal"/>
                                <VisualState x:Name="PointerOver">
                                    <Storyboard>
                                        <ObjectAnimationUsingKeyFrames Storyboard.TargetProperty="BorderBrush" Storyboard.TargetName="BorderElement">
                                            <DiscreteObjectKeyFrame KeyTime="0" Value="{ThemeResource TextControlBorderBrushPointerOver}"/>
                                        </ObjectAnimationUsingKeyFrames>
                                        <ObjectAnimationUsingKeyFrames Storyboard.TargetProperty="Background" Storyboard.TargetName="BorderElement">
                                            <DiscreteObjectKeyFrame KeyTime="0" Value="{ThemeResource TextControlBackgroundPointerOver}"/>
                                        </ObjectAnimationUsingKeyFrames>
                                        <ObjectAnimationUsingKeyFrames Storyboard.TargetProperty="Foreground" Storyboard.TargetName="PlaceholderTextContentPresenter">
                                            <DiscreteObjectKeyFrame KeyTime="0" Value="{ThemeResource TextControlPlaceholderForegroundPointerOver}"/>
                                        </ObjectAnimationUsingKeyFrames>
                                        <ObjectAnimationUsingKeyFrames Storyboard.TargetProperty="Foreground" Storyboard.TargetName="ContentElement">
                                            <DiscreteObjectKeyFrame KeyTime="0" Value="{ThemeResource TextControlForegroundPointerOver}"/>
                                        </ObjectAnimationUsingKeyFrames>
                                    </Storyboard>
                                </VisualState>
                                <VisualState x:Name="Focused">
                                    <Storyboard>
                                        <ObjectAnimationUsingKeyFrames Storyboard.TargetProperty="Foreground" Storyboard.TargetName="PlaceholderTextContentPresenter">
                                            <DiscreteObjectKeyFrame KeyTime="0" Value="{ThemeResource TextControlPlaceholderForegroundFocused}"/>
                                        </ObjectAnimationUsingKeyFrames>
                                        <ObjectAnimationUsingKeyFrames Storyboard.TargetProperty="Background" Storyboard.TargetName="BorderElement">
                                            <DiscreteObjectKeyFrame KeyTime="0" Value="{ThemeResource TextControlBackgroundFocused}"/>
                                        </ObjectAnimationUsingKeyFrames>
                                        <ObjectAnimationUsingKeyFrames Storyboard.TargetProperty="BorderBrush" Storyboard.TargetName="BorderElement">
                                            <DiscreteObjectKeyFrame KeyTime="0" Value="{ThemeResource TextControlBorderBrushFocused}"/>
                                        </ObjectAnimationUsingKeyFrames>
                                        <ObjectAnimationUsingKeyFrames Storyboard.TargetProperty="Foreground" Storyboard.TargetName="ContentElement">
                                            <DiscreteObjectKeyFrame KeyTime="0" Value="{ThemeResource TextControlForegroundFocused}"/>
                                        </ObjectAnimationUsingKeyFrames>
                                        <ObjectAnimationUsingKeyFrames Storyboard.TargetProperty="RequestedTheme" Storyboard.TargetName="ContentElement">
                                            <DiscreteObjectKeyFrame KeyTime="0" Value="Light"/>
                                        </ObjectAnimationUsingKeyFrames>
                                        <ObjectAnimationUsingKeyFrames Storyboard.TargetProperty="ShadowOpacity" Storyboard.TargetName="Shadow">
                                            <DiscreteObjectKeyFrame KeyTime="0" Value="0.7"/>
                                        </ObjectAnimationUsingKeyFrames>
                                    </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>
                        <controls:DropShadowPanel x:Name="Shadow" BlurRadius="8" OffsetX="0" OffsetY="0" ShadowOpacity="0" Color="Black" Grid.ColumnSpan="2" Grid.Row="1" Grid.RowSpan="1">
                            <Border x:Name="BorderElement" BorderBrush="{TemplateBinding BorderBrush}" BorderThickness="{TemplateBinding BorderThickness}" Background="{TemplateBinding Background}" CornerRadius="5"/>
                        </controls:DropShadowPanel>
                        <ContentPresenter x:Name="HeaderContentPresenter" Grid.ColumnSpan="2" ContentTemplate="{TemplateBinding HeaderTemplate}" Content="{TemplateBinding Header}" Foreground="{ThemeResource TextControlHeaderForeground}" FontWeight="Normal" Margin="0,0,0,8" Grid.Row="0" Visibility="Collapsed" x:DeferLoadStrategy="Lazy"/>
                        <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 TextControlPlaceholderForeground}" IsHitTestVisible="False" IsTabStop="False" Margin="{TemplateBinding BorderThickness}" Padding="{TemplateBinding Padding}" Grid.Row="1"/>
                        <Button x:Name="DeleteButton" AutomationProperties.AccessibilityView="Raw" 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>
</Page.Resources>

<Grid Background="{ThemeResource ApplicationPageBackgroundThemeBrush}">
    <TextBox Width="100" Margin="50" Height="30" Style="{StaticResource MyTextBoxStyle}" HorizontalAlignment="Left"/>
    <TextBox Width="100" Margin="50,100,0,0" Height="30" Style="{StaticResource MyTextBoxStyle}" HorizontalAlignment="Left"/>
</Grid>

To activate the shadow only when the TextBox is focused, I'm changing the DropShadowPanel's opacity from 0 to 0.7 on Focused VisualState.

(of course you need to install the toolkit as a Nuget package and add its namespace xmlns:controls="using:Microsoft.Toolkit.Uwp.UI.Controls")

And the effect looks like this:

Working sample you will find at my GitHub.