private void CreateNumpadKeyboard()
{
numpad_frame = new ContentControl();
numpad = new virtual_numpad();
numpad.number_hit_handler = new number_hit(number_entered);
numpad.submit_hit_handler = new submit_hit(submit);
numpad.backspace_hit_handler = new backspace_hit(backspace);
this.numpad_frame.Content = numpad;
numpad.parent_frame = numpad_frame;
this.numpad_frame.Background = new SolidColorBrush(Colors.White);
window_manager.main_canvas.Children.Add(numpad_frame);
this.UpdateLayout();
this.numpad_frame.Visibility = System.Windows.Visibility.Collapsed;
}