WPF 对Border 边框进行投影

<Window x:Class="WpfApp1.MainWindow"
        xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
        xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
        xmlns:d="http://schemas.microsoft.com/expression/blend/2008"
        xmlns:mc="http://schemas.openxmlformats.org/markup-compatibility/2006" 
        mc:Ignorable="d"
        Title="MainWindow" Height="450" Width="800">
    <Grid>
        <Border Margin="100" BorderThickness="1" BorderBrush="Blue">
            <Border.Effect>
                <DropShadowEffect Color="#E6EFFC"
                          Direction="320" 
                          BlurRadius="10"
                          ShadowDepth="10" />
            </Border.Effect>
            <Grid Background="White">
                <TextBlock Text="WPF 边框投影" Margin="50" FontSize="30"/>
            </Grid>
        </Border> 
    </Grid>
</Window>