WPF不活动和活动 [英] WPF inactivity and activity

问题描述

我正在尝试处理WPF应用程序中的用户不活动和活动，以淡入淡出一些内容。经过大量的研究，我决定去（至少在我看来）非常优雅的解决方案Hans Passant发布了 here 。

I'm trying to handle user inactivity and activity in a WPF application to fade some stuff in and out. After a lot of research, I decided to go with the (at least in my opinion) very elegant solution Hans Passant posted here.

只有一个缺点：只要光标停留在窗口的顶部， PreProcessInput 事件不断被触发。我有一个全屏应用程序，所以这会杀死它。任何想法如何绕过这个行为将是非常感谢。

There's only one downside: As long as the cursor stays on top of the window, the PreProcessInput event gets continously fired. I'm having a full-screen application, so this kills it. Any ideas how I can bypass this behaviour would be most appreciated.

public partial class MainWindow : Window
{
    readonly DispatcherTimer activityTimer;

    public MainWindow()
    {
        InitializeComponent();

        InputManager.Current.PreProcessInput += Activity;

        activityTimer = new DispatcherTimer
        {
            Interval = TimeSpan.FromSeconds(10),
            IsEnabled = true
        };
        activityTimer.Tick += Inactivity;
    }

    void Inactivity(object sender, EventArgs e)
    {
        rectangle1.Visibility = Visibility.Hidden; // Update
        // Console.WriteLine("INACTIVE " + DateTime.Now.Ticks);
    }

    void Activity(object sender, PreProcessInputEventArgs e)
    {
        rectangle1.Visibility = Visibility.Visible; // Update
        // Console.WriteLine("ACTIVE " + DateTime.Now.Ticks);

        activityTimer.Stop();
        activityTimer.Start();
    }
}

更新

我可以更好地缩小描述的行为（见上述代码中的 rectangle1.Visibility 更新）。只要游标位于窗口的顶部，例如控件的 Visibility 更改，则$ code> PreProcessInput 被提高也许我误会了 PreProcessInput 事件的目的，当它触发。 MSDN在这里不是很有帮助。

I could narrow down the described behaviour better (see the rectangle1.Visibility update in the above code). As long as the cursor rests on top of the window and for example the Visibility of a control is changed, the PreProcessInput is raised. Maybe I'm misunderstanding the purpose of the PreProcessInput event and when it fires. MSDN wasn't very helpful here.

推荐答案

我可以弄清楚导致描述的行为。

I could figure out what caused the described behaviour.

例如，当控件的 Visibility 更改时， PreProcessInput 事件以类型 InputReportEventArgs 的PreProcessInputEventArgs.StagingItem.Input

For example when the Visibility of a control is changed, the PreProcessInput event is raised with PreProcessInputEventArgs.StagingItem.Input of the type InputReportEventArgs.

可以避免这种行为通过过滤 InputEventArgs ，为 MouseEventArgs 和 KeyboardEventArgs OnActivity 事件，并验证是否没有按住鼠标按钮，光标的位置与应用程序处于非活动状态仍然相同。

The behaviour can be avoided by filtering the InputEventArgs for the types MouseEventArgs and KeyboardEventArgs in the OnActivity event and to verify if no mouse button is pressed and the position of the cursor is still the same as the application became inactive.

public partial class MainWindow : Window
{
    private readonly DispatcherTimer _activityTimer;
    private Point _inactiveMousePosition = new Point(0, 0);

    public MainWindow()
    {
        InitializeComponent();

        InputManager.Current.PreProcessInput += OnActivity;
        _activityTimer = new DispatcherTimer { Interval = TimeSpan.FromMinutes(5), IsEnabled = true };
        _activityTimer.Tick += OnInactivity;
    }

    void OnInactivity(object sender, EventArgs e)
    {
        // remember mouse position
        _inactiveMousePosition = Mouse.GetPosition(MainGrid);

        // set UI on inactivity
        rectangle.Visibility = Visibility.Hidden;
    }

    void OnActivity(object sender, PreProcessInputEventArgs e)
    {
        InputEventArgs inputEventArgs = e.StagingItem.Input;

        if (inputEventArgs is MouseEventArgs || inputEventArgs is KeyboardEventArgs)
        {
            if (e.StagingItem.Input is MouseEventArgs)
            {
                MouseEventArgs mouseEventArgs = (MouseEventArgs)e.StagingItem.Input;

                // no button is pressed and the position is still the same as the application became inactive
                if (mouseEventArgs.LeftButton == MouseButtonState.Released &&
                    mouseEventArgs.RightButton == MouseButtonState.Released &&
                    mouseEventArgs.MiddleButton == MouseButtonState.Released &&
                    mouseEventArgs.XButton1 == MouseButtonState.Released &&
                    mouseEventArgs.XButton2 == MouseButtonState.Released &&
                    _inactiveMousePosition == mouseEventArgs.GetPosition(MainGrid))
                    return;
            }

            // set UI on activity
            rectangle.Visibility = Visibility.Visible;

            _activityTimer.Stop();
            _activityTimer.Start();
        }
    }
}

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