private IntPtr HookCallback(int nCode, IntPtr wParam, IntPtr lParam)
{
if (nCode >= 0)
{
int vkCode = Marshal.ReadInt32(lParam);
// keep track of pressed keys so we don't intercept hotkeys
if (wParam == (IntPtr)WM_KEYDOWN || wParam == (IntPtr)WM_SYSKEYDOWN)
{
if (!keysPressed.Contains(vkCode))
{
keysPressed.Add(vkCode);
}
}
// act only when key is raised
if (wParam == (IntPtr)WM_KEYUP || wParam == (IntPtr)WM_SYSKEYUP)
{
// if more than one key was pressed before a key was raised, user attempted hotkey
if (keysPressed.Count == 1 && OnKeyPressed != null)
{
var kpa = new KeyPressedArgs(KeyInterop.KeyFromVirtualKey(vkCode));
OnKeyPressed(this, kpa);
if (kpa.Handled)
{
return(new IntPtr(1));
}
}
// reset pressed keys
keysPressed.Clear();
}
}
return(CallNextHookEx(_hookID, nCode, wParam, lParam));
}