<RadioButton.Style>
    <Style TargetType="{x:Type RadioButton}">
        <Style.Resources>
            <Style x:Key="CheckRadioFocusVisual">
                <Setter Property="Control.Template">
                    <Setter.Value>
                        <ControlTemplate>
                            <Rectangle
                                Margin="14,0,0,0"
                                StrokeThickness="1"
                                Stroke="Black"
                                StrokeDashArray="1 2"
                                SnapsToDevicePixels="true"/>
                        </ControlTemplate>
                    </Setter.Value>
                </Setter>
            </Style>
        </Style.Resources>
        <Setter Property="Foreground" Value="{DynamicResource {x:Static SystemColors.ControlTextBrushKey}}"/>
        <Setter Property="Background" Value="Transparent"/>
        <Setter Property="BorderBrush" Value="#dddddd"/>
        <Setter Property="BorderThickness" Value="1"/>
        <Setter Property="HorizontalAlignment" Value="Center"/>
        <Setter Property="VerticalAlignment" Value="Center"/>
        <Setter Property="Template">
            <Setter.Value>
                <ControlTemplate TargetType="{x:Type RadioButton}">
                    <BulletDecorator Background="Transparent">
                        <BulletDecorator.Bullet>
                            <!-- 这里是修改过的部分 开始 -->
                            <Border
                                Background="{TemplateBinding Background}"
                                BorderBrush="{TemplateBinding BorderBrush}"
                                HorizontalAlignment="{TemplateBinding HorizontalAlignment}"
                                VerticalAlignment="{TemplateBinding VerticalAlignment}"
                                SnapsToDevicePixels="{TemplateBinding SnapsToDevicePixels}">
                                <Image x:Name="PART_Image" Width="12">
                                    <Image.Source>
                                        <DrawingImage>
                                            <DrawingImage.Drawing>
                                                <GeometryDrawing Brush="OrangeRed" Geometry="M 0 0 L 3.5 4 L 7 0 Z"/>
                                            </DrawingImage.Drawing>
                                        </DrawingImage>
                                    </Image.Source>
                                    <Image.Effect>
                                        <DropShadowEffect BlurRadius="1" Opacity="0.75" ShadowDepth="0"/>
                                    </Image.Effect>
                                </Image>
                            </Border>
                            <!-- 这里是修改过的部分 结束 -->
                        </BulletDecorator.Bullet>
                        <ContentPresenter
                            Margin="{TemplateBinding Padding}"
                            VerticalAlignment="{TemplateBinding VerticalContentAlignment}"