WPFで背景が透明なウィンドウを作成する

WPFで背景が透明なウィンドウを作成する方法を紹介します。

App.xaml

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

MainWindow.xaml

WindowStyle="None"、AllowsTransparency="true"、Background="Transparent"がポイントです。

<Window
    xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
    xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
    x:Class="Lancher.MainWindow"
    x:Name="Window"
    Title="MainWindow"
    Width="640" Height="100" WindowStyle="None" AllowsTransparency="true" Background="Transparent">

    <Grid x:Name="LayoutRoot">
        <Rectangle Stroke="#FF9999A6" VerticalAlignment="Top" Height="56" RadiusX="10" RadiusY="10" StrokeThickness="2">
            <Rectangle.Fill>
                <LinearGradientBrush EndPoint="0.5,1" StartPoint="0.5,0" MappingMode="RelativeToBoundingBox">
                    <GradientStop Color="White" Offset="0"/>
                    <GradientStop Color="#FF0E3BF8" Offset="1"/>
                    <GradientStop Color="White"/>
                    <GradientStop Color="#FFFCFCFC"/>
                    <GradientStop Color="#FF2AB3FC" Offset="0.25"/>
                </LinearGradientBrush>
            </Rectangle.Fill>
        </Rectangle>
    </Grid>
</Window>