调用系统API,XP和win7是不是有差别啊！

Question

我需要用一个键盘钩子和鼠标钩子来控制键盘鼠标，但是我在windows7下面使用没有任何问题。到了XP环境下面就发现，装载钩子是好的，但是卸载钩子后，键盘按键就不正常了，按键不对应了，特别是alt,ctrl,shift这几个键。
难道XP环境和windows7环境下有什么区别吗？class KeyBoardHook
    {
        //委托  
        public delegate int HookProc(int nCode, int wParam, IntPtr lParam);
        static int hHook = 0;
        public const int WH_KEYBOARD_LL = 13;
        //LowLevel键盘截获，如果是WH_KEYBOARD＝2，并不能对系统键盘截取，Acrobat Reader会在你截取之前获得键盘。  
        HookProc KeyBoardHookProcedure;
        //键盘Hook结构函数  
        [StructLayout(LayoutKind.Sequential)]
        public class KeyBoardHookStruct
        {
            public int vkCode;
            public int scanCode;
            public int flags;
            public int time;
            public int dwExtraInfo;
        }
        #region DllImport
        //设置钩子  
        [DllImport("user32.dll")]
        public static extern int SetWindowsHookEx(int idHook, HookProc lpfn, IntPtr hInstance, int threadId);
        [DllImport("user32.dll", CharSet = CharSet.Auto, CallingConvention = CallingConvention.StdCall)]
        //抽掉钩子  
        public static extern bool UnhookWindowsHookEx(int idHook);
        [DllImport("user32.dll")]
        //调用下一个钩子  
        public static extern int CallNextHookEx(int idHook, int nCode, int wParam, IntPtr lParam);        [DllImport("kernel32.dll")]
        public static extern int GetCurrentThreadId();        [DllImport("kernel32.dll")]
        public static extern IntPtr GetModuleHandle(string name);        #endregion
        #region 自定义事件        public void Hook_Start()
        {
            // 安装键盘钩子  
            if (hHook == 0)
            {
                KeyBoardHookProcedure = new HookProc(KeyBoardHookProc);                //hHook = SetWindowsHookEx(2, 
                //            KeyBoardHookProcedure, 
                //          GetModuleHandle(Process.GetCurrentProcess().MainModule.ModuleName), GetCurrentThreadId());                 hHook = SetWindowsHookEx(WH_KEYBOARD_LL,
                          KeyBoardHookProcedure,
                        GetModuleHandle(Process.GetCurrentProcess().MainModule.ModuleName), 0);                //如果设置钩子失败.  
                if (hHook == 0)
                {
                    Hook_Clear();
                    throw new Exception("设置Hook失败!");
                }
            }
        }        //取消钩子事件  
        public void Hook_Clear()
        {
            bool retKeyboard = true;
            if (hHook != 0)
            {
                retKeyboard = UnhookWindowsHookEx(hHook);
                hHook = 0;
            }
            //如果去掉钩子失败.  
            if (!retKeyboard) throw new Exception("UnhookWindowsHookEx failed.");
        }        //这里可以添加自己想要的信息处理  
        public static int KeyBoardHookProc(int nCode, int wParam, IntPtr lParam)
        {
            if (nCode >= 0)
            {
                KeyBoardHookStruct kbh = (KeyBoardHookStruct)Marshal.PtrToStructure(lParam, typeof(KeyBoardHookStruct));                return 1;                          }
            return CallNextHookEx(hHook, nCode, wParam, lParam);
        }
        #endregion