.NET将像素转换为点并创建错误的图像大小

<Window x:Class="test_image_resizing.MainWindow"
    xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
    xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
    Title="MainWindow" WindowState="Maximized" Loaded="Window_Loaded">
    <Grid> 
        <Image 
            x:Name="test"  
            VerticalAlignment="Top" 
            HorizontalAlignment="Center" 
            Stretch="None" 
            Source="/test%20image%20resizing;component/Resources/Test.png" />
    </Grid>
</Window>

private void Window_Loaded(object sender, RoutedEventArgs e)
{
    MessageBox.Show("test=" + test.ActualWidth.ToString());
}