ShadowBorder

A decorator control that renders a drop shadow behind its child content. Provides customizable shadow color, blur radius, offset, and corner radius with cached bitmap rendering for performance.

Basic usage

<ShadowBorder ShadowColor="#80000000"
              BlurRadius="12"
              Offset="0,4"
              CornerRadius="8">
    <Border Background="White" CornerRadius="8" Padding="16">
        <TextBlock Text="Content with shadow" />
    </Border>
</ShadowBorder>

Properties

Property	Type	Default	Description
ShadowColor	Color	Colors.Black	Color of the shadow
BlurRadius	double	12	Blur radius of the shadow in pixels
Offset	Vector	0,4	X/Y offset of the shadow
CornerRadius	CornerRadius	0	Corner radius for the shadow (matches content corners)

Shadow color

Customize the shadow color:

<!-- Black shadow (default) -->
<ShadowBorder ShadowColor="Black" />

<!-- Semi-transparent black -->
<ShadowBorder ShadowColor="#80000000" />

<!-- Colored shadow -->
<ShadowBorder ShadowColor="#4000AAFF" />

Blur radius

Control the softness of the shadow:

<!-- Sharp shadow -->
<ShadowBorder BlurRadius="4" />

<!-- Soft shadow (default) -->
<ShadowBorder BlurRadius="12" />

<!-- Very soft shadow -->
<ShadowBorder BlurRadius="24" />

Offset

Adjust the shadow position:

<!-- Downward shadow (default) -->
<ShadowBorder Offset="0,4" />

<!-- Upward shadow -->
<ShadowBorder Offset="0,-4" />

<!-- Rightward shadow -->
<ShadowBorder Offset="4,0" />

<!-- Diagonal shadow -->
<ShadowBorder Offset="2,2" />

Corner radius

Match the shadow to rounded content:

<ShadowBorder CornerRadius="8">
    <Border Background="White" CornerRadius="8" Padding="16">
        <!-- Content -->
    </Border>
</ShadowBorder>

Performance

The shadow bitmap is cached and only regenerated when:

• The child content size changes
• Shadow properties (color, blur, offset, corner radius) change
• The control is detached from the visual tree

This caching ensures good performance even with complex shadows.

Example

<ShadowBorder ShadowColor="#40000000"
              BlurRadius="16"
              Offset="0,8"
              CornerRadius="12">
    <Border Background="White"
            CornerRadius="12"
            Padding="20"
            BoxShadow="none">
        <StackPanel Spacing="8">
            <TextBlock Text="Card Title" FontWeight="Bold" FontSize="18" />
            <TextBlock Text="Card content goes here" />
        </StackPanel>
    </Border>
</ShadowBorder>