透明色で塗りつぶす

アプリ実行

ソースコード

App.xaml

<Application x:Class="HelloWorld.App"
             xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
             xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
             StartupUri="MainWindow.xaml">
</Application>

MainWindow.xaml

<Window x:Class="HelloWold.MainWindow"
        xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
        xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
        Title="MainWindow" Height="200" Width="300">
    <UniformGrid Background="Aqua">
        <!-- 半分の不透明度の白で塗りつぶす -->
        <Rectangle Height="150" Width="200" Fill="#88FFFFFF"></Rectangle>
    </UniformGrid>
</Window>