Question

I’m programming a WPF application, and I’d like to raise an event if the user has not interacted with the program for 30 seconds. That is to say, no keyboard or/and mouse events.

The reason I want do do this is because I want to bring attention to the screen if a variable alertstate has been set to true.

I’m thinking of using something along the lines of BackgroundWorker but I really don’t know how I can get the time a user has not interacted with the program. Can someone point me in the right direction?

I guess this question basically comes down to checking if a user has interacted with the screen. How do I do this?

Answer 1

You need to record the last time the user moved the mouse or pressed a key and then check if that time is greater than your threshold.

So you need to add mouse move, mouse click and keyboard handlers to your application (this is Silverlight code so you might have to change namespaces etc.):

private void AttachEvents()
{
    Application.Current.RootVisual.MouseMove += new MouseEventHandler(RootVisual_MouseMove);
    Application.Current.RootVisual.KeyDown += new KeyEventHandler(RootVisual_KeyDown);

    Application.Current.RootVisual.AddHandler(UIElement.MouseLeftButtonDownEvent, (MouseButtonEventHandler)RootVisual_MouseButtonDown, true);
    Application.Current.RootVisual.AddHandler(UIElement.MouseRightButtonDownEvent, (MouseButtonEventHandler)RootVisual_MouseButtonDown, true);
}

Then in the handlers have code like this for the mouse move:

private void RootVisual_MouseMove(object sender, MouseEventArgs e)
{
    timeOfLastActivity = DateTime.Now;
}

and a similar one for the KeyDown event handler.

You will have to set off a timer:

idleTimer = new DispatcherTimer();
idleTimer.Interval = TimeSpan.FromSeconds(1);
idleTimer.Tick += new EventHandler(idleTimer_Tick);

// Initialise last activity time
timeOfLastActivity = DateTime.Now;

Then in the tick event handler have something like this:

private void idleTimer_Tick(object sender, EventArgs e)
{
    if (DateTime.Now > timeOfLastActivity.AddSeconds(30))
    {
        // Do your stuff
    }
}