/// <summary>
/// Low level hook func that is invoked by windows whenever there is a
/// global keyboard event
/// </summary>
/// <param name="nCode">the code</param>
/// <param name="wParam">wParam</param>
/// <param name="lParam">lParam</param>
/// <returns>-1 if handled, otherwise if not handled</returns>
public int HookProc(int nCode, IntPtr wParam, IntPtr lParam)
{
bool handled = false;
if (nCode >= 0)
{
var keyboardLLHookStruct = (KBDLLHOOKSTRUCT)Marshal.PtrToStructure(lParam, typeof(KBDLLHOOKSTRUCT));
var wmKeyboard = (KeyboardWParam)wParam;
notifyEvent(wmKeyboard, keyboardLLHookStruct, ref handled);
}
return(handled ? -1 : User32Interop.CallNextHookEx(_hookHandle, nCode, wParam, lParam));
}