WP7 VisualState以编程方式更改

我正在尝试创建一个图像，当它被触摸时，会出现一个小弹出窗口。当你再次触摸它（或在外面的任何地方）时，它应该会消失
我已经创建了弹出窗口，以及一些隐藏和折叠的视觉状态转换

<Grid x:Name="LayoutRoot" Background="Transparent">
    <VisualStateManager.VisualStateGroups>
                <VisualStateGroup x:Name="PopupVisibility">
                    <VisualState x:Name="PopupVisible">
                        <Storyboard>
                            <ObjectAnimationUsingKeyFrames Storyboard.TargetProperty="(UIElement.Visibility)" Storyboard.TargetName="PopupControl">
                                <DiscreteObjectKeyFrame KeyTime="0">
                                    <DiscreteObjectKeyFrame.Value>
                                        <Visibility>Visible</Visibility>
                                    </DiscreteObjectKeyFrame.Value>
                                </DiscreteObjectKeyFrame>
                            </ObjectAnimationUsingKeyFrames>
                            <DoubleAnimationUsingKeyFrames Storyboard.TargetProperty="(UIElement.Opacity)" Storyboard.TargetName="PopupControl">
                                <EasingDoubleKeyFrame KeyTime="0" Value="0"/>
                                <EasingDoubleKeyFrame KeyTime="0:0:0.5" Value="1"/>
                            </DoubleAnimationUsingKeyFrames>
                            <DoubleAnimationUsingKeyFrames Storyboard.TargetProperty="(UIElement.RenderTransform).(CompositeTransform.ScaleX)" Storyboard.TargetName="PopupControl">
                                <EasingDoubleKeyFrame KeyTime="0" Value="0"/>
                                <EasingDoubleKeyFrame KeyTime="0:0:0.5" Value="1"/>
                            </DoubleAnimationUsingKeyFrames>
                            <DoubleAnimationUsingKeyFrames Storyboard.TargetProperty="(UIElement.RenderTransform).(CompositeTransform.ScaleY)" Storyboard.TargetName="PopupControl">
                                <EasingDoubleKeyFrame KeyTime="0" Value="0"/>
                                <EasingDoubleKeyFrame KeyTime="0:0:0.5" Value="1"/>
                            </DoubleAnimationUsingKeyFrames>
                        </Storyboard>
                    </VisualState>
                    <VisualState x:Name="PopupCollapsed">
                        <Storyboard>
                            <DoubleAnimation Duration="0:0:0.5" To="0" Storyboard.TargetProperty="(UIElement.RenderTransform).(CompositeTransform.ScaleX)" Storyboard.TargetName="PopupControl" d:IsOptimized="True"/>
                            <DoubleAnimation Duration="0:0:0.5" To="0" Storyboard.TargetProperty="(UIElement.RenderTransform).(CompositeTransform.ScaleY)" Storyboard.TargetName="PopupControl" d:IsOptimized="True"/>
                            <DoubleAnimation Duration="0:0:0.5" To="0" Storyboard.TargetProperty="(UIElement.Opacity)" Storyboard.TargetName="PopupControl" d:IsOptimized="True"/>
                            <ObjectAnimationUsingKeyFrames Storyboard.TargetProperty="(UIElement.Visibility)" Storyboard.TargetName="PopupControl">
                                <DiscreteObjectKeyFrame KeyTime="0:0:0.5">
                                    <DiscreteObjectKeyFrame.Value>
                                        <Visibility>Visible</Visibility>
                                    </DiscreteObjectKeyFrame.Value>
                                </DiscreteObjectKeyFrame>
                                <DiscreteObjectKeyFrame KeyTime="0:0:0.7">
                                    <DiscreteObjectKeyFrame.Value>
                                        <Visibility>Collapsed</Visibility>
                                    </DiscreteObjectKeyFrame.Value>
                                </DiscreteObjectKeyFrame>
                            </ObjectAnimationUsingKeyFrames>
                        </Storyboard>
                    </VisualState>
                </VisualStateGroup>
            </VisualStateManager.VisualStateGroups>
<Button Content="Text" HorizontalAlignment="Right" Margin="0,0,12,-37" Width="152" Background="#00C06B6B" Height="75" VerticalAlignment="Bottom" Visibility="Visible">
            <Custom:Interaction.Triggers>
                <Custom:EventTrigger EventName="Click">
                    <ic:GoToStateAction x:Name="GoToStatePopupVisible" StateName="PopupVisible"/>
                </Custom:EventTrigger>
                <Custom:EventTrigger EventName="LostFocus">
                    <ic:GoToStateAction x:Name="LostFocus" StateName="PopupCollapsed"/>
                </Custom:EventTrigger>
            </Custom:Interaction.Triggers>
        </Button>
 <Grid x:Name="PopupControl" Height="241" Margin="39,-28,203,0" Grid.Row="1" VerticalAlignment="Top" RenderTransformOrigin="0.5,0.5">


                <Grid.RenderTransform>
                <CompositeTransform/>
            </Grid.RenderTransform>
            <Rectangle Stroke="Black">
                <Rectangle.Fill>
                    <LinearGradientBrush EndPoint="0.5,1" StartPoint="0.5,0">
                        <GradientStop Color="#FF726969" Offset="1"/>
                        <GradientStop Color="White"/>
                    </LinearGradientBrush>
                </Rectangle.Fill>
            </Rectangle>
            <TextBlock TextWrapping="Wrap" Text="TextBlock" d:LayoutOverrides="Width" Foreground="#FF1D0E0E" Margin="5"/>
        </Grid>
<Image HorizontalAlignment="Right" Height="100" Margin="0,-38,37,0" Grid.Row="1" VerticalAlignment="Top" Width="100" Source="Images/pushpin.jpg" ManipulationStarted="Image_ManipulationStarted">
        </Image>
</Grid>

我尝试使用Blend来测试这一点，效果很好，例如，添加一个按钮并创建一个事件触发器：

<Button Content="Text" HorizontalAlignment="Right" Margin="0,0,12,-37" Width="152" Background="#00C06B6B" Height="75" VerticalAlignment="Bottom" Visibility="Visible">
            <Custom:Interaction.Triggers>
                <Custom:EventTrigger EventName="Click">
                    <ic:GoToStateAction x:Name="GoToStatePopupVisible" StateName="PopupVisible"/>
                </Custom:EventTrigger>
                <Custom:EventTrigger EventName="LostFocus">
                    <ic:GoToStateAction x:Name="LostFocus" StateName="PopupCollapsed"/>
                </Custom:EventTrigger>
            </Custom:Interaction.Triggers>
        </Button>

然而，当尝试"真实"的东西时，我需要更多的逻辑。如果我按下图像，它是可见的，我希望它过渡到塌陷，反之亦然。所以我保存了我当前的可见性状态

(VisualStateManager.GetVisualStateGroups(LayoutRoot)[0] as VisualStateGroup).CurrentStateChanged += new EventHandler<VisualStateChangedEventArgs>(MainPage_CurrentStateChanged);
public string CurrentState { get; set; }
        void MainPage_CurrentStateChanged(object sender, VisualStateChangedEventArgs e)
        {
            CurrentState = e.NewState.Name;
        }

然后我创建图像：

<Image HorizontalAlignment="Right" Height="100" Margin="0,-38,37,0" Grid.Row="1" VerticalAlignment="Top" Width="100" Source="Images/pushpin.jpg" ManipulationStarted="Image_ManipulationStarted">
            </Image>

最后，我通过编程尝试做与事件触发器相同的事情，但有一些逻辑：

private void Image_ManipulationStarted(object sender, ManipulationStartedEventArgs e)
        {
            switch (CurrentState)
            {
                case "PopupVisible":
                    {
                        ExtendedVisualStateManager.GoToElementState(LayoutRoot, "PopupCollapsed", true);
                        break;
                    }
                case "PopupCollapsed":
                    {
                        ExtendedVisualStateManager.GoToElementState(LayoutRoot, "PopupVisible", true);
                        break;
                    }
            }
        }

我尝试了VisualStateManager和ExtendedVisualStateManager方法GoToState和GoToElementState，但都没有成功。方法总是返回false，并且屏幕上没有任何更改。我做错了什么？？