private void OnButtonUp(object sender, ButtonEventArgs e)
{
// Show a modal dialog window
// Create and show new window
SecondWindow wnd = new SecondWindow();
wnd.Visibility = Visibility.Visible;
wnd.Topmost = true; // move on top of all others
DispatcherFrame modalFrame = new DispatcherFrame();
// Create a handler that will terminate the loop when the window will be hidden
PropertyChangedEventHandler handler = delegate
{
if (wnd.Visibility != Visibility.Visible) // when the windows was hidden
modalFrame.Continue = false; // tell the frame to exit the loop
};
wnd.IsVisibleChanged += handler; // add handler to terminate the loop
Dispatcher.PushFrame(modalFrame); // start the loop and block the calling thread
// Here we go when the modal dialog was closed
wnd.IsVisibleChanged -= handler; // remove handler
}