/// <summary>
/// Callback function called by the operating system when a keyboard message is processed.
/// This function adds data relative to the keyboard message to the <see cref="m_HookQueue"/> queue.
/// </summary>
/// <param name="nCode">A code the hook procedure uses to determine how to process the message.
/// If nCode is less than zero, the hook procedure must pass the message to the <see cref="CallNextHookEx(IntPtr, int, int, IntPtr)"/>
/// function without further processing and should return the value returned by <see cref="CallNextHookEx(IntPtr, int, int, IntPtr)"/>.</param>
/// <param name="wParam">The identifier of the keyboard message.</param>
/// <param name="lParam">A pointer to a <see cref="KBDLLHOOKSTRUCT"/> structure.</param>
/// <returns>If returns <see cref="IntPtr.Zero"/> other message hooks in the queue are not processed,
/// otherwise processing continues normally.</returns>
private IntPtr HookCallBack(int nCode, IntPtr wParam, IntPtr lParam)
{
if (nCode >= 0)
{
KeyData data = new KeyData((User32Helper.WM)wParam.ToInt32(), lParam);
m_HookQueue.Add(data);
}
return(User32Helper.CallNextHookEx(m_HookID, nCode, wParam, lParam));
}
/// <summary>
/// This method runs in a separateed thread and takec care to process the generated keyboard messages firing
/// <see cref="KeyStatusChanged"/> event according with defined <see cref="Filters"/>.
/// </summary>
private void Worker()
{
while (true)
{
KeyData data = m_HookQueue.Take();
if (data == null)
{
return;
}
data.FormatData();
if ((Filters.Count(f => f.CanCombine) == 0 ||
Filters.Where(f => f.CanCombine).Any(f => f.Apply(data))) &&
Filters.Where(f => !f.CanCombine).All(f => f.Apply(data)))
{
KeyStatusChanged?.Invoke(data);
}
}
}
