WPF设置ListBoxItem失去焦点时的背景色

 <Style TargetType="ListBoxItem">
    <Style.Resources>
        <!--SelectedItem with focus-->
        <SolidColorBrush x:Key="{x:Static SystemColors.HighlightBrushKey}" Color="LightBlue" Opacity=".4"/>
        <!--SelectedItem without focus-->
        <SolidColorBrush x:Key="{x:Static SystemColors.ControlBrushKey}" Color="LightBlue" Opacity=".4"/>
    </Style.Resources>
</Style>