private static void CheckHook(object obj, EventArgs args)
{
HOOK old_hook = m_hook;
// Reinstall the hook in case Windows disabled it without telling us. It’s
// OK to have two hooks installed for a short time, because we check for
// recursive calls to ourselves in OnKey().
if (m_active)
{
m_hook = NativeMethods.SetWindowsHookEx(WH.KEYBOARD_LL, m_callback,
NativeMethods.LoadLibrary("user32.dll"), 0);
if (m_hook == HOOK.INVALID)
{
Log.Debug("Unable to install hook: {0}",
new Win32Exception(Marshal.GetLastWin32Error()));
}
}
else
{
m_hook = HOOK.INVALID;
}
if (old_hook != HOOK.INVALID)
{
// XXX: this will crash if the hook is not removed from the same
// thread that installed it.
int ret = NativeMethods.UnhookWindowsHookEx(old_hook);
if (ret == 0)
{
Log.Debug("Unable to uninstall hook: {0}",
new Win32Exception(Marshal.GetLastWin32Error()));
}
}
}
public static void Fini()
{
// XXX: this will crash if called from the GC Finalizer Thread because
// the hook needs to be removed from the same thread that installed it.
if (m_hook != HOOK.INVALID)
{
int ret = NativeMethods.UnhookWindowsHookEx(m_hook);
if (ret == 0)
throw new Win32Exception(Marshal.GetLastWin32Error());
m_hook = HOOK.INVALID;
}
m_callback = null;
}
public static void Init()
{
if (Environment.OSVersion.Platform == PlatformID.Win32NT
|| Environment.OSVersion.Platform == PlatformID.Win32S
|| Environment.OSVersion.Platform == PlatformID.Win32Windows
|| Environment.OSVersion.Platform == PlatformID.WinCE)
{
m_callback = OnKey; // Keep a reference on OnKey
m_hook = NativeMethods.SetWindowsHookEx(WH.KEYBOARD_LL, m_callback,
NativeMethods.LoadLibrary("user32.dll"), 0);
if (m_hook == HOOK.INVALID)
throw new Win32Exception(Marshal.GetLastWin32Error());
}
}
public static extern int CallNextHookEx(HOOK hhk, HC nCode, WM wParam,
IntPtr lParam);
public static extern int UnhookWindowsHookEx(HOOK hhk);
