Error with pinvoke function getKeyBoardLayout()

Question

I'm trying to write a basic background keylogger... Keyboard scanCodes and States are converted via pinvoke functions ToAsciiEx or ToUnicodeEx. These function have an argument for KeyboardLayout. I have a function (see below) for getting the current (active windows) keyboard layout. But this functions always returns 0. Error code is 6 (ERROR_INVALID_HANDLE).

Any sugessions ?

thx for answers

    static public IntPtr getActiveKeyBoardLayout() 
    {             
        int handle = 0;
        handle = GetForegroundWindow();

        IntPtr i = new IntPtr(handle);
        HandleRef hr = new HandleRef(wrapper, i);
        int pid;
        GetWindowThreadProcessId(hr, out pid);

        IntPtr layout = GetKeyboardLayout(pid);

        int er = Marshal.GetLastWin32Error();
        if (er > 0)
        {
            System.Console.Out.WriteLine("error " + er.ToString());
        }

        return layout;
    }

Answer 1

You are passing a process ID to the function. It requires a thread ID. The return value of GetWindowThreadProcessId(). The way you use Marshal.GetLastWin32Error() is wrong too, you should only use it when an API function returned a failure code.