WPF event when a window is no longer on top

Question

I have a WPF window (window1) whose owner is window2. If a user clicks on window2, or the desktop, or anything else to make window1 not on top of the z-order, I want to set window1's visibility to hidden. I.e., the window either needs to be on top, or hidden. Is this possible?

Answer 1

Yes.

public Window1()
{
    InitializeComponent();    
    this.Deactivated += new EventHandler(Window1_Deactivated);
}

void Window1_Deactivated(object sender, EventArgs e)
{
    Visibility = Visibility.Collapsed;
}

Note that this will also remove it from the TaskBar.