单击XAML仅清除按钮单击组合框

Question

我想在按钮点击时清除组合框选择/内容，所有这些都在XAML中，没有代码。我正确使用故事板吗？我需要一个故事板吗？

我在ItemsControl中，所以浏览可视树并不容易，也很难看。

<StackPanel Orientation="Horizontal" 
            HorizontalAlignment="Center">
    <TextBlock FontSize="20" 
               Text="Sensitivity Parameter: "  
               VerticalAlignment="Center"/>
    <ComboBox x:Name="cbSensitivityParameter2" 
              FontSize="20" 
              DisplayMemberPath="Name" 
              VerticalAlignment="Center">
        <ComboBox.ItemsSource>
            <MultiBinding Converter="{StaticResource parameter2SensitivityNameListConverter}" 
                         UpdateSourceTrigger="PropertyChanged" 
                         Mode="OneWay">
                <Binding ElementName="tbUserLevel" 
                         Path="IsChecked"/>
                <Binding Path="Parameters"/>
            </MultiBinding>
        </ComboBox.ItemsSource>
    </ComboBox>
    <Button Style="{DynamicResource MetroCircleButtonStyle}" 
            Width="50" 
            Height="50" 
            Margin="10,0,0,0" 
            Visibility="{Binding ElementName=cbSensitivityParameter2, Path=SelectedIndex, Converter={StaticResource hideMeConverter}, UpdateSourceTrigger=PropertyChanged}" VerticalAlignment="Center">
        <Rectangle Width="20" Height="20">
            <Rectangle.Fill>
                <VisualBrush Stretch="Fill" 
                             Visual="{StaticResource appbar_delete}" />
            </Rectangle.Fill>
        </Rectangle>
        <Button.Triggers>
            <EventTrigger RoutedEvent="Button.Click">
                <BeginStoryboard>
                    <Storyboard>
                        <SingleAnimationUsingKeyFrames Storyboard.TargetName="cbSensitivityParameter2" Storyboard.TargetProperty="SelectedIndex">
                            <LinearSingleKeyFrame Value="-1" />
                        </SingleAnimationUsingKeyFrames>
                    </Storyboard>
                </BeginStoryboard>
            </EventTrigger>
        </Button.Triggers>
    </Button>
</StackPanel>

谢谢！