我要求WPF在发生空闲事件时重复播放视频，并在检测到用户活动时恢复到上一个窗口。
为此，我跟随马丁·布伯尔（Martin Buberl）回答的https://stackoverflow.com/a/4970019/6696609。
在XAML中，我具有VideoGrid和WindowGrid Grid，通过检测空闲事件，我改变了彼此的可见性。
以下是说明问题https://github.com/DavidSilwal/wpfvideoissue的说明的源代码 假定空闲事件发生在5秒。当您单击按钮时，空闲事件在10秒时发生。
除了
之外，它都可以正常工作对于按钮单击的第一个空闲事件，VideoGrid尝试可见，但不可见（它只是闪烁），然后每个下一个空闲事件都可以正常工作。
感谢您提供反馈和建议以消除眨眼问题。
// set UI on inactivity
private void OnInactivity(object sender, EventArgs e)
{
_inactiveMousePosition = Mouse.GetPosition(this);
System.Windows.Application.Current.Dispatcher.BeginInvoke(new Action(() =>
{
if (WindowGrid.Visibility == Visibility.Visible)
{
WindowGrid.Visibility = Visibility.Collapsed;
}
if (VideoGrid.Visibility == Visibility.Collapsed)
{
WindowState = WindowState.Maximized;
WindowStyle = WindowStyle.None;
//play video
videoplayer.Play();
VideoGrid.Visibility = Visibility.Visible;
}
}));
}
private void OnActivity(object sender, PreProcessInputEventArgs e)
{
var inputEventArgs = e.StagingItem.Input;
if (inputEventArgs is System.Windows.Input.MouseEventArgs || inputEventArgs is KeyboardEventArgs)
{
if (e.StagingItem.Input is System.Windows.Input.MouseEventArgs)
{
var mouseEventArgs = (System.Windows.Input.MouseEventArgs)e.StagingItem.Input;
// no button is pressed and the position is still the same as the application became inactive
if (!(
mouseEventArgs.LeftButton == MouseButtonState.Pressed ||
mouseEventArgs.RightButton == MouseButtonState.Pressed ||
mouseEventArgs.MiddleButton == MouseButtonState.Pressed ||
mouseEventArgs.XButton1 == MouseButtonState.Pressed ||
mouseEventArgs.XButton2 == MouseButtonState.Pressed
//|| _inactiveMousePosition != mouseEventArgs.GetPosition(this)
))
{
return;
}
}
// set UI on activity
System.Windows.Application.Current.Dispatcher.BeginInvoke(new Action(() =>
{
if (VideoGrid.Visibility == Visibility.Visible)
{
WindowState = WindowState.Normal;
WindowStyle = WindowStyle.SingleBorderWindow;
//stop video
videoplayer.Stop();
VideoGrid.Visibility = Visibility.Collapsed;
}
if (WindowGrid.Visibility == Visibility.Collapsed)
{
WindowGrid.Visibility = Visibility.Visible;
}
}));
_activityTimer.Stop();
_activityTimer.Start();
}
}
答案 0 :(得分：2)
通过调试代码，我可以给您一个答案，但可能不是一个令人满意的答案。
我在OnInactivity中为您的代码添加了一些调试输出...
private async void OnInactivity(object sender, EventArgs e)
{
// remember mouse position
_inactiveMousePosition = Mouse.GetPosition(this);
// set UI on inactivity
Debug.WriteLine ( DateTime.Now.ToString("HH:mm:ss.fffffff") + " Inactivity" ) ;
await System.Windows.Application.Current.Dispatcher.InvokeAsync(new Action(() =>
{
Grid1.Visibility = Visibility.Collapsed;
videoplayer.Play();
Grid2.Visibility = Visibility.Visible;
}));
}
以及在OnActivity中...
private async void OnActivity(object sender, PreProcessInputEventArgs e)
{
var inputEventArgs = e.StagingItem.Input;
if (inputEventArgs is System.Windows.Input.MouseEventArgs || inputEventArgs is KeyboardEventArgs)
{
if (e.StagingItem.Input is System.Windows.Input.MouseEventArgs)
{
var mouseEventArgs = (System.Windows.Input.MouseEventArgs)e.StagingItem.Input;
if (!(
mouseEventArgs.LeftButton == MouseButtonState.Pressed ||
mouseEventArgs.RightButton == MouseButtonState.Pressed ||
mouseEventArgs.MiddleButton == MouseButtonState.Pressed ||
mouseEventArgs.XButton1 == MouseButtonState.Pressed ||
mouseEventArgs.XButton2 == MouseButtonState.Pressed
|| _inactiveMousePosition != mouseEventArgs.GetPosition(this)
))
{
return;
}
}
Debug.WriteLine ( DateTime.Now.ToString("HH:mm:ss.fffffff") + " Activity " + inputEventArgs.RoutedEvent.ToString() ) ;
// set UI on activity
await System.Windows.Application.Current.Dispatcher.InvokeAsync(new Action(() =>
{
videoplayer.Stop();
Grid1.Visibility = Visibility.Visible;
Grid2.Visibility = Visibility.Hidden;
}));
_activityTimer.Stop();
_activityTimer.Start();
}
}
按下按钮后，这里显示的是一点输出：
23:45:31.0583181 Activity Mouse.MouseMove
23:45:31.0643177 Activity Mouse.QueryCursor
23:45:31.0653178 Activity Mouse.PreviewMouseMove
23:45:31.0663188 Activity Mouse.MouseMove
23:45:31.0723180 Activity Mouse.QueryCursor
23:45:31.0753176 Activity Mouse.PreviewMouseMove
23:45:31.0763193 Activity Mouse.MouseMove
23:45:36.0722537 Inactivity
23:45:36.0752537 Activity Keyboard.PreviewGotKeyboardFocus
23:45:36.0782576 Activity Keyboard.PreviewKeyboardInputProviderAcquireFocus
23:45:36.0802536 Activity Keyboard.KeyboardInputProviderAcquireFocus
23:45:36.0832529 Activity Keyboard.LostKeyboardFocus
23:45:36.0842549 Activity Keyboard.GotKeyboardFocus
23:45:41.1041883 Inactivity
23:45:42.4981698 Activity Mouse.QueryCursor
23:45:42.5001740 Activity Mouse.PreviewMouseMove
23:45:42.5031736 Activity Mouse.MouseMove
23:45:42.5071741 Activity Mouse.QueryCursor
23:45:42.5091736 Activity Mouse.PreviewMouseMove
23:45:42.5111735 Activity Mouse.MouseMove
闲置5秒钟后，它会尝试开始播放视频，但立即会引起一些与焦点改变有关的事件。
我想这意味着单击按钮会使按钮成为焦点。开始播放视频会使视频失去焦点，从而产生一些事件。
我能够通过过滤掉这些事件来解决问题。这是我对OnActivity函数的修改版本，在其中我按名称过滤了这些事件：
private async void OnActivity(object sender, PreProcessInputEventArgs e)
{
var inputEventArgs = e.StagingItem.Input;
switch ( inputEventArgs.RoutedEvent.Name )
{
case "PreviewGotKeyboardFocus":
case "PreviewKeyboardInputProviderAcquireFocus":
case "KeyboardInputProviderAcquireFocus":
case "LostKeyboardFocus":
case "GotKeyboardFocus":
return ;
}
if (inputEventArgs is System.Windows.Input.MouseEventArgs || inputEventArgs is KeyboardEventArgs)
{
if (e.StagingItem.Input is System.Windows.Input.MouseEventArgs)
{
var mouseEventArgs = (System.Windows.Input.MouseEventArgs)e.StagingItem.Input;
if (!(
mouseEventArgs.LeftButton == MouseButtonState.Pressed ||
mouseEventArgs.RightButton == MouseButtonState.Pressed ||
mouseEventArgs.MiddleButton == MouseButtonState.Pressed ||
mouseEventArgs.XButton1 == MouseButtonState.Pressed ||
mouseEventArgs.XButton2 == MouseButtonState.Pressed
|| _inactiveMousePosition != mouseEventArgs.GetPosition(this)
))
{
return;
}
}
// set UI on activity
await System.Windows.Application.Current.Dispatcher.InvokeAsync(new Action(() =>
{
videoplayer.Stop();
Grid1.Visibility = Visibility.Visible;
Grid2.Visibility = Visibility.Hidden;
}));
_activityTimer.Stop();
_activityTimer.Start();
}
}
我不知道是否应该过滤掉其他事件，也不知道按事件名称过滤是否是最好的方法。