xaml - ScrollViewer reaching bottom WindowsPhone8

Question

Im trying to open a App-Bar when the user reaches the end of the (ScrollViewer)Page... Therefore I need a indicator when the end is reached...

• My Scrollviewer (maybe because WP8) has no "ViewChanged"-event like posted in other questions
• And this solution is just overkill for my Problem I think: http://blogs.msdn.com/b/slmperf/archive/2011/06/30/windows-phone-mango-change-listbox-how-to-detect-compression-end-of-scroll-states.aspx

I cant find any event within this Viewer which could help me...

       <ScrollViewer x:Name="SV_ScrollViewer"
                      Grid.Row="1" 
                      Margin="12,0,12,0"
                      ManipulationMode="Control"                       
                      AllowDrop="False">
            <Grid x:Name="ContentPanel">
                <StackPanel>
                    <Controls:Map                             
                        Height="730"
                        x:Name="M_MainMap"                                  
                        ZoomLevel="10" 
                        Loaded="Map_Loaded"/>
                    <phone:LongListSelector 
                        x:Name="LLS_FuelStations" 
                        Height="700">                        
                    </phone:LongListSelector>
                </StackPanel>                    
            </Grid>
        </ScrollViewer>

Thank you for your help!

2-EDIT: The LayoutUpdated-Event was not good for closing app-bar again... I ended up with a Dispatcher-Timer for closing AND opening it. Now it works fine (smooth):

    // Constructor
    public MainPage()
    {
        InitializeComponent();           

        Dispatcher.BeginInvoke(() =>
        {
            //initialize timer
            if (timer == null)
            {
                int timerSpan = 500;
                timer = new DispatcherTimer { Interval = TimeSpan.FromMilliseconds(timerSpan) };
                timer.Tick += (o, arg) => OffsetWatcher();
            }
        });
    }  

Closing and opening app-bar:

private void OffsetWatcher()
        {
            if (SV_ScrollViewer.ScrollableHeight - SV_ScrollViewer.VerticalOffset > 100 )
            {
                if (ApplicationBar.IsVisible)
                {
                    ApplicationBar.IsVisible = false;
                    ApplicationBar.IsMenuEnabled = false;
                }
            }
            else
            {
                if (!ApplicationBar.IsVisible)
                {
                    BuildLocalizedApplicationBar();
                }   
            }
        }

Answer 1

使用更新的布局这是我使用和调试以获得滚动效果的代码。您可能还需要跟踪指针被按下的位置以及滚动查看器操作完成事件。这是在 xaml 后面的代码中添加相应的事件处理程序。

 <ScrollViewer ManipulationCompleted="ScrollViewer_ManipulationCompleted" ManipulationMode="All">
        <StackPanel  LayoutUpdated="StackPanel_LayoutUpdated" PointerPressed="StackPanel_PointerPressed">
            <Grid Height="100" Width="100" Background="Red" ></Grid>
            <Grid Height="100" Width="100" Background="Green" ></Grid>
            <Grid Height="100" Width="100" Background="Blue" ></Grid>
            <Grid Height="100" Width="100" Background="Yellow" ></Grid>
            <Grid Height="100" Width="100" Background="Red" ></Grid>
            <Grid Height="100" Width="100" Background="Green" ></Grid>
            <Grid Height="100" Width="100" Background="Blue" ></Grid>
            <Grid Height="100" Width="100" Background="Yellow" ></Grid>
            <Grid Height="100" Width="100" Background="Red" ></Grid>
            <Grid Height="100" Width="100" Background="Green" ></Grid>
            <Grid Height="100" Width="100" Background="Blue" ></Grid>
            <Grid Height="100" Width="100" Background="Yellow" ></Grid>
            <Grid Height="100" Width="100" Background="Red" ></Grid>
            <Grid Height="100" Width="100" Background="Green" ></Grid>
            <Grid Height="100" Width="100" Background="Blue" ></Grid>
            <Grid Height="100" Width="100" Background="Yellow" ></Grid>
            <Grid Height="100" Width="100" Background="Red" ></Grid>
            <Grid Height="100" Width="100" Background="Green" ></Grid>
            <Grid Height="100" Width="100" Background="Blue" ></Grid>
            <Grid Height="100" Width="100" Background="Yellow" ></Grid>
            <Grid Height="100" Width="100" Background="Red" ></Grid>
            <Grid Height="100" Width="100" Background="Green" ></Grid>
            <Grid Height="100" Width="100" Background="Blue" ></Grid>
            <Grid Height="100" Width="100" Background="Yellow" ></Grid>
            <Grid Height="100" Width="100" Background="Red" ></Grid>
            <Grid Height="100" Width="100" Background="Green" ></Grid>
            <Grid Height="100" Width="100" Background="Blue" ></Grid>
            <Grid Height="100" Width="100" Background="Yellow" ></Grid>
            <Grid Height="100" Width="100" Background="Red" ></Grid>
            <Grid Height="100" Width="100" Background="Green" ></Grid>
            <Grid Height="100" Width="100" Background="Blue" ></Grid>
            <Grid Height="100" Width="100" Background="Yellow" ></Grid>
            <Grid Height="100" Width="100" Background="Red" ></Grid>
            <Grid Height="100" Width="100" Background="Green" ></Grid>
            <Grid Height="100" Width="100" Background="Blue" ></Grid>
            <Grid Height="100" Width="100" Background="Yellow" ></Grid>
        </StackPanel>
    </ScrollViewer>

这是后面的代码

        public MainPage()
    {
        this.InitializeComponent();
    }

    /// <summary>
    /// Invoked when this page is about to be displayed in a Frame.
    /// </summary>
    /// <param name="e">Event data that describes how this page was reached.  The Parameter
    /// property is typically used to configure the page.</param>
    protected override void OnNavigatedTo(NavigationEventArgs e)
    {

    }


    private void ScrollViewer_ManipulationCompleted(object sender, ManipulationCompletedRoutedEventArgs e)
    {
        //scroll bar being dragged
    }

    private void StackPanel_LayoutUpdated(object sender, object e)
    {
        //if swipe gesture then check for vertical offset and carry on with the //calculations you have to do else do nothing
    }

    private void StackPanel_PointerPressed(object sender, PointerRoutedEventArgs e)
    {
        //swipe gesture being made
    }

请让我知道它是否有效