RoutedEventConverter 无法处理 Checked 事件

checkBox有这样的模板

  <ControlTemplate x:Key="CustomCheckBox" TargetType="CheckBox">
            <StackPanel Orientation="Horizontal" Margin="11, 0, 0, 0">                
                <Canvas VerticalAlignment="Center" Width="30" Height="19" Margin="{TemplateBinding Padding}">
                    <Ellipse x:Name="CheckBoxBackCircle" Width="50" Height="50" Fill="#F8F8FA" Opacity="0">
                        <Ellipse.RenderTransform>
                            <TranslateTransform X="-15" Y="-15"/>
                        </Ellipse.RenderTransform>
                    </Ellipse>
                    <Path x:Name="CheckBoxSquare" Data="M.5,12.5 l0,4 q0,2 2,2 l15,0 q1,0 1,-2 l0,-14 q0,-2 -2,-2 l-15,0 q-1,0 -1,2 l0,10" Stroke="#D6D9DF" StrokeThickness="1.4" StrokeDashArray="69.5" Fill="White" Stretch="Fill" Width="20" Height="20"/>
                    <Path x:Name="CheckBoxCheck" Data="M.5,12.5 l7,6 l11,-15" Stroke="#D6D9DF" StrokeThickness="1.4" StrokeDashArray="28" StrokeDashOffset="28" />
                </Canvas>
                <ContentControl VerticalAlignment="Center" Content="{TemplateBinding Content}"></ContentControl>
            </StackPanel>

        <ControlTemplate.Triggers>
            <EventTrigger RoutedEvent="MouseEnter">
                <EventTrigger.Actions>

                    <BeginStoryboard>
                        <Storyboard TargetName="CheckBoxBackCircle" TargetProperty="Opacity">
                            <DoubleAnimation To="1" Duration="0:0:0:0.2" FillBehavior="HoldEnd"></DoubleAnimation>                                
                        </Storyboard>
                    </BeginStoryboard>

                    <BeginStoryboard>
                        <Storyboard TargetName="CheckBoxSquare" TargetProperty="Stroke.Color">
                            <ColorAnimation To="#6FA2F6" Duration="0:0:0:0.2" FillBehavior="HoldEnd"></ColorAnimation>                                
                        </Storyboard>
                    </BeginStoryboard>

                </EventTrigger.Actions>
            </EventTrigger>
            <EventTrigger RoutedEvent="MouseLeave">
                <EventTrigger.Actions>

                    <BeginStoryboard>
                        <Storyboard TargetName="CheckBoxBackCircle" TargetProperty="Opacity">
                            <DoubleAnimation To="0" Duration="0:0:0:0.2" FillBehavior="HoldEnd"></DoubleAnimation>
                        </Storyboard>
                    </BeginStoryboard>

                    <BeginStoryboard>
                        <Storyboard TargetName="CheckBoxSquare" TargetProperty="Stroke.Color">
                            <ColorAnimation To="#D6D9DF" Duration="0:0:0:0.2" FillBehavior="HoldEnd"></ColorAnimation>
                        </Storyboard>
                    </BeginStoryboard>

                </EventTrigger.Actions>
            </EventTrigger>

            <EventTrigger RoutedEvent="Checked">
                <EventTrigger.Actions>
                    <BeginStoryboard>
                        <Storyboard TargetName="CheckBoxSquare" TargetProperty="StrokeDashOffset">
                            <DoubleAnimation To="-69.5" Duration="0:0:0:1" FillBehavior="HoldEnd"/>
                        </Storyboard>
                    </BeginStoryboard>
                </EventTrigger.Actions>
            </EventTrigger>
        </ControlTemplate.Triggers>
    </ControlTemplate>

问题是这个触发器。

            <EventTrigger RoutedEvent="Checked">
                <EventTrigger.Actions>
                    <BeginStoryboard>
                        <Storyboard TargetName="CheckBoxSquare" TargetProperty="StrokeDashOffset">
                            <DoubleAnimation To="-69.5" Duration="0:0:0:1" FillBehavior="HoldEnd"/>
                        </Storyboard>
                    </BeginStoryboard>
                </EventTrigger.Actions>
            </EventTrigger>

这是带有此模板的复选框

<CheckBox Template="{StaticResource CustomCheckBox}" FontSize="17" HorizontalAlignment="Center"></CheckBox>

错误：

如果为属性设置不同的值RoutedEvent，例如 MouseMove，那么一切都会正常工作（但似乎这不适用于所有事件，因为Click和Unchecked会弹出相同的错误）。

请帮帮我！