C# 当用户在触摸屏上从ScrollViewer中抬起手指时，会触发什么事件
我发现当我点击ScrollViewer时，PointerPressed和PointerExit事件会按预期触发。但是，如果我在触摸屏幕后向任何方向滚动并抬起手指，则除了PointerCaptureLost（指针捕捉丢失）之外，没有任何事件触发，它会在我滚动时过早触发 当我捕获指针ID并使用计时器轮询指针点的状态时，即使在滚动后抬起手指，IsInContact标志仍然为true。当我轻触屏幕时，它就如预期的那样工作了 操纵完成具有与上面相同的效果，并且我不能使用ViewChanged事件，因为它在我抬起手指之前触发 这是一个错误还是我遗漏了什么？当用户将手指从屏幕上移开时，是否有其他方法可以检测到？这简直让我发疯 下面是示例代码。您需要在触摸模式下使用模拟器，或使用具有触摸功能的屏幕来测试： 代码：C# 当用户在触摸屏上从ScrollViewer中抬起手指时，会触发什么事件,c#,xaml,windows-runtime,windows-store-apps,winrt-xaml,C#,Xaml,Windows Runtime,Windows Store Apps,Winrt Xaml,我发现当我点击ScrollViewer时，PointerPressed和PointerExit事件会按预期触发。但是，如果我在触摸屏幕后向任何方向滚动并抬起手指，则除了PointerCaptureLost（指针捕捉丢失）之外，没有任何事件触发，它会在我滚动时过早触发 当我捕获指针ID并使用计时器轮询指针点的状态时，即使在滚动后抬起手指，IsInContact标志仍然为true。当我轻触屏幕时，它就如预期的那样工作了 操纵完成具有与上面相同的效果，并且我不能使用ViewChanged事件，因为它在
using System;
using Windows.UI.Input;
using Windows.UI.Xaml;
using Windows.UI.Xaml.Controls;
using Windows.UI.Xaml.Input;
namespace App1
{
public sealed partial class MainPage : Page
{
private readonly DispatcherTimer pointerTimer = new DispatcherTimer();
private uint? CurrentPointerID; //container for the current pointer id when user makes contact with the screeen
public MainPage()
{
this.InitializeComponent();
scrollviewer.PointerPressed += scrollviewer_PointerPressed;
scrollviewer.PointerMoved += scrollviewer_PointerMoved;
scrollviewer.PointerExited += scrollviewer_PointerExited;
scrollviewer.PointerReleased += scrollviewer_PointerReleased;
scrollviewer.PointerCaptureLost += scrollviewer_PointerCaptureLost;
scrollviewer.PointerCanceled += scrollviewer_PointerCanceled;
pointerTimer.Tick += pointerTimer_Tick;
pointerTimer.Interval = TimeSpan.FromMilliseconds(300);
pointerTimer.Start();
}
#region ScrollViewer Events
void scrollviewer_PointerMoved(object sender, PointerRoutedEventArgs e)
{
EventCalledTextBlock.Text = "Pointer Moved";
}
void scrollviewer_PointerExited(object sender, PointerRoutedEventArgs e)
{
EventCalledTextBlock.Text = "Pointer Exited";
}
void scrollviewer_PointerPressed(object sender, PointerRoutedEventArgs e)
{
CurrentPointerID = e.Pointer.PointerId;
EventCalledTextBlock.Text = "Pointer Pressed";
}
void scrollviewer_PointerCanceled(object sender, PointerRoutedEventArgs e)
{
EventCalledTextBlock.Text = "Pointer Canceled";
}
void scrollviewer_PointerCaptureLost(object sender, PointerRoutedEventArgs e)
{
EventCalledTextBlock.Text = "Capture Lost";
}
void scrollviewer_PointerReleased(object sender, PointerRoutedEventArgs e)
{
EventCalledTextBlock.Text = "Pointer Released";
}
#endregion
void pointerTimer_Tick(object sender, object e)
{
if (!CurrentPointerID.HasValue)
{
PollingTextBlock.Text = string.Empty;
return;
}
try
{
var pointerPoint = PointerPoint.GetCurrentPoint(CurrentPointerID.Value);
PollingTextBlock.Text = pointerPoint.IsInContact ? "Is In Contact" : "Not in Contact";
}
catch (Exception ex)
{
//This exception is raised when the user lifts finger without dragging.
//assume finger is not in contact with screen
PollingTextBlock.Text = "Not in Contact";
}
}
}
}
<Page
x:Class="App1.MainPage"
xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
xmlns:local="using:App1"
xmlns:d="http://schemas.microsoft.com/expression/blend/2008"
xmlns:mc="http://schemas.openxmlformats.org/markup-compatibility/2006"
mc:Ignorable="d">
<Grid Background="{ThemeResource ApplicationPageBackgroundThemeBrush}" Name="grid">
<Grid.RowDefinitions>
<RowDefinition Height="113*"/>
<RowDefinition Height="655*"/>
</Grid.RowDefinitions>
<ScrollViewer x:Name="scrollviewer" VerticalScrollBarVisibility="Disabled" HorizontalScrollBarVisibility="Visible" Grid.Row="1" >
<Rectangle Fill="#FF3783CF" Height="100" Stroke="#FF33D851" Width="{Binding ElementName=grid, Path=ActualWidth}" Margin="100" StrokeThickness="4" />
</ScrollViewer>
<StackPanel Orientation="Vertical" Margin="45,25,0,0">
<StackPanel Orientation="Horizontal">
<TextBlock HorizontalAlignment="Left" TextWrapping="Wrap" Text="Event Called:" VerticalAlignment="Top" FontSize="24" Margin="0,0,20,0"/>
<TextBlock x:Name="EventCalledTextBlock" HorizontalAlignment="Left" TextWrapping="Wrap" VerticalAlignment="Top" FontSize="24"/>
</StackPanel>
<StackPanel Orientation="Horizontal">
<TextBlock HorizontalAlignment="Left" TextWrapping="Wrap" Text="Polling Value:" VerticalAlignment="Top" FontSize="24" Margin="0,0,20,0"/>
<TextBlock x:Name="PollingTextBlock" HorizontalAlignment="Left" TextWrapping="Wrap" VerticalAlignment="Top" FontSize="24"/>
</StackPanel>
</StackPanel>
</Grid>
</Page>
using System;
using Windows.UI.Input;
using Windows.UI.Xaml;
using Windows.UI.Xaml.Controls;
using Windows.UI.Xaml.Input;
namespace App1
{
public sealed partial class MainPage : Page
{
private readonly DispatcherTimer pointerTimer = new DispatcherTimer();
private uint? CurrentPointerID; //container for the current pointer id when user makes contact with the screeen
public MainPage()
{
this.InitializeComponent();
scrollviewer.PointerPressed += scrollviewer_PointerPressed;
scrollviewer.PointerMoved += scrollviewer_PointerMoved;
scrollviewer.PointerExited += scrollviewer_PointerExited;
scrollviewer.PointerReleased += scrollviewer_PointerReleased;
scrollviewer.PointerCaptureLost += scrollviewer_PointerCaptureLost;
scrollviewer.PointerCanceled += scrollviewer_PointerCanceled;
pointerTimer.Tick += pointerTimer_Tick;
pointerTimer.Interval = TimeSpan.FromMilliseconds(300);
pointerTimer.Start();
}
#region ScrollViewer Events
void scrollviewer_PointerMoved(object sender, PointerRoutedEventArgs e)
{
EventCalledTextBlock.Text = "Pointer Moved";
}
void scrollviewer_PointerExited(object sender, PointerRoutedEventArgs e)
{
EventCalledTextBlock.Text = "Pointer Exited";
}
void scrollviewer_PointerPressed(object sender, PointerRoutedEventArgs e)
{
CurrentPointerID = e.Pointer.PointerId;
EventCalledTextBlock.Text = "Pointer Pressed";
}
void scrollviewer_PointerCanceled(object sender, PointerRoutedEventArgs e)
{
EventCalledTextBlock.Text = "Pointer Canceled";
}
void scrollviewer_PointerCaptureLost(object sender, PointerRoutedEventArgs e)
{
EventCalledTextBlock.Text = "Capture Lost";
}
void scrollviewer_PointerReleased(object sender, PointerRoutedEventArgs e)
{
EventCalledTextBlock.Text = "Pointer Released";
}
#endregion
void pointerTimer_Tick(object sender, object e)
{
if (!CurrentPointerID.HasValue)
{
PollingTextBlock.Text = string.Empty;
return;
}
try
{
var pointerPoint = PointerPoint.GetCurrentPoint(CurrentPointerID.Value);
PollingTextBlock.Text = pointerPoint.IsInContact ? "Is In Contact" : "Not in Contact";
}
catch (Exception ex)
{
//This exception is raised when the user lifts finger without dragging.
//assume finger is not in contact with screen
PollingTextBlock.Text = "Not in Contact";
}
}
}
}
<Page
x:Class="App1.MainPage"
xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
xmlns:local="using:App1"
xmlns:d="http://schemas.microsoft.com/expression/blend/2008"
xmlns:mc="http://schemas.openxmlformats.org/markup-compatibility/2006"
mc:Ignorable="d">
<Grid Background="{ThemeResource ApplicationPageBackgroundThemeBrush}" Name="grid">
<Grid.RowDefinitions>
<RowDefinition Height="113*"/>
<RowDefinition Height="655*"/>
</Grid.RowDefinitions>
<ScrollViewer x:Name="scrollviewer" VerticalScrollBarVisibility="Disabled" HorizontalScrollBarVisibility="Visible" Grid.Row="1" >
<Rectangle Fill="#FF3783CF" Height="100" Stroke="#FF33D851" Width="{Binding ElementName=grid, Path=ActualWidth}" Margin="100" StrokeThickness="4" />
</ScrollViewer>
<StackPanel Orientation="Vertical" Margin="45,25,0,0">
<StackPanel Orientation="Horizontal">
<TextBlock HorizontalAlignment="Left" TextWrapping="Wrap" Text="Event Called:" VerticalAlignment="Top" FontSize="24" Margin="0,0,20,0"/>
<TextBlock x:Name="EventCalledTextBlock" HorizontalAlignment="Left" TextWrapping="Wrap" VerticalAlignment="Top" FontSize="24"/>
</StackPanel>
<StackPanel Orientation="Horizontal">
<TextBlock HorizontalAlignment="Left" TextWrapping="Wrap" Text="Polling Value:" VerticalAlignment="Top" FontSize="24" Margin="0,0,20,0"/>
<TextBlock x:Name="PollingTextBlock" HorizontalAlignment="Left" TextWrapping="Wrap" VerticalAlignment="Top" FontSize="24"/>
</StackPanel>
</StackPanel>
</Grid>
</Page>
我认为您需要使用PointerReleased事件。
请参阅以下链接：我无意中发现了这个问题，因为我正在与一个类似的问题作斗争。我有一个ScrollViewer，其中有几个图像，我想知道当ScrollViewer停止移动时会显示哪些图像 最后，我使用了ScrollViewer.ViewChanged事件。此事件一直触发，直到滚动结束 事实上，我只对这些事件中的最后一个感兴趣，但由于没有任何事件只在特定时刻触发，我需要对这一事件作出反应，并检查自己是否是采取行动的适当时机 我希望这有帮助
ScrollViewer.ViewChanged事件：您是否尝试过操纵事件而不是指针事件？是。它会产生与上面相同的行为，其中在滚动后从未调用过OperationCompleted。我想知道ScrollViewer中的矩形是否正在“吞噬”指针释放事件。理论不错，但是当我通过（（UIElement）ScrollViewer.Content）将指针事件添加到矩形时，它们根本不会触发。另外，在矩形上设置操纵模式允许引发Scrollviewer上的PointerExit事件，但是这会禁用一起滚动。嗯，我记得在MSDN文档中读到，PointerReleased事件并不总是必须触发。它给出了若干理由说明为什么会出现这种情况。找到了。请查看“不要依赖总是成对发生的PointerPressed和PointerReleased事件。要正常运行，您的应用程序必须侦听并处理所有代表新闻行动可能结论的事件。”以下是链接：