How do I intercept a keyboard entry before it is entered into an edit box? I have:

```
<Window x:Class="X.MainWindow"
        KeyDown="Window_KeyDown"
        >

private void Window_KeyDown(object sender, KeyEventArgs e)
{
    if (e.Key == Key.Add) 
        return;
}//Window_KeyDown

```

Pressing the "+" button on the numeric section of the keyboard is detected. It also places a "+" into one of my edit boxes. How do I prevent that from happening?