ho risolto.
quello che mi serviva era chiudere il programma con Ctrl+Q.
ho fatto cosi:
codice:
<Window x:Class="B2B.MainWindow"
        xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
        xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
        Title="B2B" Height="800" Width="800" WindowStartupLocation="CenterScreen" ResizeMode="NoResize">
    <Window.InputBindings>
        <KeyBinding Modifiers="Control" Key="Q" Command="{Binding exitCmd}" />
    </Window.InputBindings>
    ..........................
</Window>
poi nella corrispettiva classe:
codice:
   public MainWindow()
        {
            InitializeComponent();
            AddKeys();
        }

        private void AddKeys()
        {
            RoutedCommand exitCmd = new RoutedCommand();
            exitCmd.InputGestures.Add(new KeyGesture(Key.Q, ModifierKeys.Control));
            CommandBindings.Add(new CommandBinding(exitCmd, ExitHandler));
        }

        private void ExitHandler(object sender, ExecutedRoutedEventArgs e)
        {
            this.Close();
        }
ciao!