默认格式

<Style x:Key="RadioButtonStyle" TargetType="{x:Type RadioButton}">
    <Setter Property="FocusVisualStyle" Value="{StaticResource FocusVisual}"/>
    <Setter Property="Background" Value="{StaticResource RadioButton.Static.Background}"/>
    <Setter Property="BorderBrush" Value="{StaticResource RadioButton.Static.Border}"/>
    <Setter Property="Foreground" Value="{DynamicResource {x:Static SystemColors.ControlTextBrushKey}}"/>
    <Setter Property="BorderThickness" Value="1"/>
    <Setter Property="Template">
        <Setter.Value>
            <ControlTemplate TargetType="{x:Type RadioButton}">
                <Grid x:Name="templateRoot" Background="Transparent" SnapsToDevicePixels="True">
                    <Grid.ColumnDefinitions>
                        <ColumnDefinition Width="Auto"/>
                        <ColumnDefinition Width="*"/>
                    </Grid.ColumnDefinitions>
                    <!--CornerRadius="100"  最大大小就是200 超过200 不是正圆-->
                    <Border x:Name="radioButtonBorder"
                            Background="{TemplateBinding Background}"
                            BorderBrush="{TemplateBinding BorderBrush}" 
                            BorderThickness="{TemplateBinding BorderThickness}" 
                            CornerRadius="100" 
                            Grid.Column="0"
                            HorizontalAlignment="{TemplateBinding HorizontalContentAlignment}" 
                            Margin="1,1,2,1" 
                            VerticalAlignment="{TemplateBinding VerticalContentAlignment}">
                        <Grid x:Name="markGrid" Margin="2">
                            <Ellipse x:Name="optionMark" 
                                     Fill="{StaticResource RadioButton.Static.Glyph}" 
                                     MinWidth="6" 
                                     MinHeight="6" 
                                     Opacity="0"/>
                        </Grid>
                    </Border>
                    <ContentPresenter x:Name="contentPresenter" 
                                      Grid.Column="1" 
                                      Focusable="False" 
                                      HorizontalAlignment="{TemplateBinding HorizontalContentAlignment}"
                                      Margin="{TemplateBinding Padding}" 
                                      RecognizesAccessKey="True" 
                                      SnapsToDevicePixels="{TemplateBinding SnapsToDevicePixels}" 
                                      VerticalAlignment="{TemplateBinding VerticalContentAlignment}"/>
                </Grid>
                <ControlTemplate.Triggers>
                    <Trigger Property="HasContent" Value="true">
                        <Setter Property="FocusVisualStyle" Value="{StaticResource OptionMarkFocusVisual}"/>
                        <Setter Property="Padding" Value="4,-1,0,0"/>
                    </Trigger>
                    <Trigger Property="IsMouseOver" Value="true">
                        <Setter Property="Background" TargetName="radioButtonBorder" Value="{StaticResource RadioButton.MouseOver.Background}"/>
                        <Setter Property="BorderBrush" TargetName="radioButtonBorder" Value="{StaticResource RadioButton.MouseOver.Border}"/>
                        <Setter Property="Fill" TargetName="optionMark" Value="{StaticResource RadioButton.MouseOver.Glyph}"/>
                    </Trigger>
                    <Trigger Property="IsEnabled" Value="false">
                        <Setter Property="Background" TargetName="radioButtonBorder" Value="{StaticResource RadioButton.Disabled.Background}"/>
                        <Setter Property="BorderBrush" TargetName="radioButtonBorder" Value="{StaticResource RadioButton.Disabled.Border}"/>
                        <Setter Property="Fill" TargetName="optionMark" Value="{StaticResource RadioButton.Disabled.Glyph}"/>
                    </Trigger>
                    <Trigger Property="IsPressed" Value="true">
                        <Setter Property="Background" TargetName="radioButtonBorder" Value="{StaticResource RadioButton.Pressed.Background}"/>
                        <Setter Property="BorderBrush" TargetName="radioButtonBorder" Value="{StaticResource RadioButton.Pressed.Border}"/>
                        <Setter Property="Fill" TargetName="optionMark" Value="{StaticResource RadioButton.Pressed.Glyph}"/>
                    </Trigger>
                    <Trigger Property="IsChecked" Value="true">
                        <Setter Property="Opacity" TargetName="optionMark" Value="1"/>
                    </Trigger>
                    <Trigger Property="IsChecked" Value="{x:Null}">
                        <Setter Property="Opacity" TargetName="optionMark" Value="0.56"/>
                    </Trigger>
                </ControlTemplate.Triggers>
            </ControlTemplate>
        </Setter.Value>
    </Setter>
</Style>

解释

1. Border: 定义了单选按钮的外观，设置了宽度、高度、边框颜色和厚度，并使用圆角（CornerRadius）创建圆形按钮。
2. ContentPresenter: 用于显示按钮的内容，可以是文本或其他控件。
3. Triggers: 定义了两种触发器，当IsChecked属性为True时，背景颜色变为蓝色；当IsEnabled属性为False时，背景颜色变为灰色。

自定义模板

 <Style x:Key="RadioButtonStyleDemo" TargetType="{x:Type RadioButton}">
     <Setter Property="FocusVisualStyle" Value="{x:Null}"/>
     <Setter Property="Background" Value="Transparent"/>
     <Setter Property="BorderBrush" Value="#333"/>
     <Setter Property="Foreground" Value="#333"/>
     <Setter Property="BorderThickness" Value="1"/>
     <Setter Property="Template">
         <Setter.Value>
             <ControlTemplate TargetType="{x:Type RadioButton}">
                 <Grid>
                     <Grid.ColumnDefinitions>
                         <ColumnDefinition Width="auto" />
                         <ColumnDefinition />
                     </Grid.ColumnDefinitions>
                     <Border Grid.Column="0"  Width="16" Height="16">
                         <Grid>
                             <Ellipse x:Name="OuterCircle" 
                                  Fill="{TemplateBinding Background}" 
                                  Stroke="{TemplateBinding BorderBrush}" 
                                  StrokeThickness="1"/>
                             <Ellipse x:Name="InnerCircle" 
                                  Width="8" 
                                  Height="8" 
                                  Fill="Blue" 
                                  Visibility="Hidden"/>
                         </Grid>
                     </Border>
                     <ContentPresenter Margin="4,0,0,0" 
                                       Grid.Column="1"
                                       VerticalAlignment="Center" 
                                       HorizontalAlignment="Left" 
                                       RecognizesAccessKey="True"/>
                 </Grid>
                 <ControlTemplate.Triggers>
                     <Trigger Property="IsChecked" Value="True">
                         <Setter TargetName="InnerCircle" Property="Visibility" Value="Visible"/>
                     </Trigger>
                     <Trigger Property="IsEnabled" Value="False">
                         <Setter TargetName="OuterCircle" Property="Fill" Value="Gray"/>
                     </Trigger>
                 </ControlTemplate.Triggers>
             </ControlTemplate>
         </Setter.Value>
     </Setter>
 </Style>

解释

1. Grid: 使用Grid容器来包含两个Ellipse元素，一个是外圈（OuterCircle），一个是内圈（InnerCircle）。
2. OuterCircle: 定义了单选按钮的外圈，使用Background和BorderBrush属性。
3. InnerCircle: 定义了单选按钮的内圈，默认情况下隐藏（Visibility设置为Hidden）。
4. Triggers: 当IsChecked属性为True时，显示内圈；当IsEnabled属性为False时，外圈的填充颜色变为灰色。

样式：