删除默认事件点击ExpandedView（Windows Phone）

Question

当我执行DoubleTap时，我希望属性ExpandedView.IsExpanded更改为值“true”，而不是在我执行Tap时。我怎样才能做到这一点？我认为我必须删除工具包ExpandedView中的默认事件Tap，但我不确切知道。

<toolkit:ExpanderView x:Name="ExpandedItem">
                                <toolkit:ExpanderView.Header>
                                    <StackPanel x:Name="ItemChat" Height="93" Margin="0,6,0,0">
                                        <StackPanel Orientation="Horizontal" Width="420" Height="85" Margin="0,0,0,6">
                                           <StackPanel Height="85" Width="208">
                                                <TextBlock Text="Timer" Padding="0,2,0,0" VerticalAlignment="Top" HorizontalAlignment="Left" 
                                                    Width="186" Height="52" FontSize="{StaticResource PhoneFontSizeLarge}" Margin="15,0,0,0"/>
                                                <TextBlock Text="Later" VerticalAlignment="Bottom" HorizontalAlignment="Left" 
                                                    Width="207" Height="33" FontSize="{StaticResource PhoneFontSizeSmall}" Foreground="#FF2190AC" Margin="15,0,0,0"/>
                                            </StackPanel>
                                            <StackPanel Height="85" Width="91">
                                                <TextBlock Text="some" Padding="3,12,0,0" 
                                                    Width="91" Height="52" FontSize="{StaticResource PhoneFontSizeNormal}" Margin="0"/>
                                                <es:RegularPolygon x:Name="TrianguloExpandible" Fill="#FF888888" Height="10" InnerRadius="1" PointCount="3" Stretch="Fill" Stroke="White" Width="20" Margin="50,8,0,0" StrokeThickness="0"/>
                                            </StackPanel>
                                        </StackPanel>
                                        <Rectangle Fill="#FFDADADA" Height="1" Width="382" HorizontalAlignment="Left" Margin="35,0,5,0"/>
                                    </StackPanel>
                                </toolkit:ExpanderView.Header>
                                <toolkit:ExpanderView.Items>
                                    <TextBlock FontSize="40" Text="Expanded Content 1" Foreground="Orange"/>
                                    <TextBlock FontSize="40" Text="Expanded Content 2" Foreground="YellowGreen"/>
                                </toolkit:ExpanderView.Items>
                            </toolkit:ExpanderView>