Global Windows Key Press

I have a simple WPF application and I need to capture F1 key pressed in Windows (Operation System), even if my WPF window is minimized, or it isn't activated.

I have problems with detecting this. I searched on Internet and I found many results, but they didn't helped me.

For detecting a key pressed inside of application I used this simple code:

AddHandler(Keyboard.KeyDownEvent, (KeyEventHandler)KeyPressed);
private void KeyPressed(object sender, KeyEventArgs e)
{
      if (e.Key == Key.F1)
      {
           //my code went here
      }
}

But this doesn't work when my window isn't activated.

So, my question is: how to detect global key press?

I repeat: It is a WPF application.