title: How to control led from several keyboard separated
body: <p>Now I'm doing a project. </p>
  
  <p>There are several keyboards connect to the computer. I use <code>keybd_event()</code> to control the led, but when I turn on the led (such as numlock led), the numlock led of all the keyboard will turn on too. </p>
  
  <p>I want to control led separated, that mean when I turn on the led of one keyboard, the corresponding led of rest keyboard will not turn on.</p>
  
  <p>I do this in C#. Does anyone have any idea?</p>