WPF inactivity and activity

Question

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 opin

Answer 1

I implements the solution in a IdleDetector class. I have improved a little bit the code. The Iddle detector throw an IsIdle That can be intercepte ! It give that ! I wait for some comments.

public class IdleDetector
{
    private readonly DispatcherTimer _activityTimer;
    private Point _inactiveMousePosition = new Point(0, 0);

    private IInputElement _inputElement;
    private int _idleTime = 300;

    public event EventHandler IsIdle;

    public IdleDetector(IInputElement inputElement, int idleTime)
    {
        _inputElement = inputElement;
        InputManager.Current.PreProcessInput += OnActivity;
        _activityTimer = new DispatcherTimer { Interval = TimeSpan.FromSeconds(idleTime), IsEnabled = true };
        _activityTimer.Tick += OnInactivity;
    }

    public void ChangeIdleTime(int newIdleTime)
    {
        _idleTime = newIdleTime;

        _activityTimer.Stop();
        _activityTimer.Interval = TimeSpan.FromSeconds(newIdleTime);
        _activityTimer.Start();
    }

    void OnInactivity(object sender, EventArgs e)
    {
        _inactiveMousePosition = Mouse.GetPosition(_inputElement);
        _activityTimer.Stop();
        IsIdle?.Invoke(this, new EventArgs());
    }

    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(_inputElement))
                    return;
            }

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