Public Const GWL_WNDPROC = -4
Public Const GWL_USERDATA = (-21)

Public Declare Function SetWindowLong Lib "user32" Alias "SetWindowLongA" (ByVal hWnd As Long, ByVal nIndex As Long, ByVal dwNewLong As Long) As Long

Public Function Hook(ByVal hWnd As Long) As Long

    Dim pOld As Long
    '指定自定义的窗口过程
    pOld = SetWindowLong(hWnd, GWL_WNDPROC, AddressOf WindowProc)
    '保存原来默认的窗口过程指针
    SetWindowLong hWnd, GWL_USERDATA, pOld
    Hook = pOld
End Function

        public const short GWL_WNDPROC = -4;
        public const short GWL_USERDATA = (-21);

        [DllImport("user32", EntryPoint = "SetWindowLongA", ExactSpelling = true, CharSet = CharSet.Ansi, SetLastError = true)]
        public static extern int SetWindowLong(int hWnd, int nIndex, int dwNewLong);

        public static int Hook(int hWnd)
        {
            int returnValue;
            int pOld;
            pOld = System.Convert.ToInt32(SetWindowLong(hWnd, System.Convert.ToInt32(GWL_WNDPROC), System.Convert.ToInt32(new int(WindowProc))));
            SetWindowLong(hWnd, System.Convert.ToInt32(GWL_USERDATA), pOld);
            returnValue = pOld;
            return returnValue;
        }

pOld = System.Convert.ToInt32(SetWindowLong(hWnd, System.Convert.ToInt32(GWL_WNDPROC), System.Convert.ToInt32(new int(WindowProc))));

public const int GWL_WNDPROC  = -4;
        public const int GWL_USERDATA = -21;

        public delegate IntPtr NewWndProc(IntPtr hWnd, int msg, IntPtr wParam, IntPtr lParam);

        private NewWndProc wpr = null;

        //备份的默认处理函数
        private IntPtr oldWndProc = IntPtr.Zero;

        [DllImport("user32", EntryPoint = "SetWindowLongA", ExactSpelling = true, CharSet = CharSet.Ansi, SetLastError = true)]
        public static extern IntPtr SetWindowLong(IntPtr hWnd, int nIndex, NewWndProc dwNewLong);

        [DllImport("user32.dll", CharSet = CharSet.Auto)]
        public static extern IntPtr CallWindowProc(IntPtr wndProc, IntPtr hWnd, int msg, IntPtr wParam, IntPtr lParam);

        /// <summary>
        /// 
        /// </summary>
        /// <param name="hWnd"></param>
        /// <param name="msg"></param>
        /// <param name="wParam"></param>
        /// <param name="lParam"></param>
        /// <returns></returns>
        private IntPtr GridControlWndProc(IntPtr hWnd, int msg, IntPtr wParam, IntPtr lParam)
        {
            IntPtr returnVar = IntPtr.Zero;   
            
            // 你的操作。。。

            returnVar = CallWindowProc(oldWndProc, hWnd, msg, wParam, lParam);
            return returnVar;
        }

        /// <summary>
        /// 
        /// </summary>
        /// <param name="hWnd"></param>
        /// <returns></returns>
        public IntPtr Hook(IntPtr hWnd)
        {                       
            IntPtr returnValue = IntPtr.Zero;
            wpr = new NewWndProc(this.GridControlWndProc);
            IntPtr pOld = SetWindowLong(hWnd, GWL_WNDPROC, wpr);
            SetWindowLong(hWnd, GWL_USERDATA, (NewWndProc)Marshal.GetDelegateForFunctionPointer(pOld,typeof(NewWndProc)));
            returnV