Attribute VB_Name = "Module1"
Public Declare Function SetWindowLong Lib "user32" _
                Alias "SetWindowLongA" _
                (ByVal hwnd As Long, _
                ByVal nIndex As Long, _
                ByVal dwNewLong As Long) _
                As Long

Public Declare Function GetWindowLong Lib "user32" _
                Alias "GetWindowLongA" _
                (ByVal hwnd As Long, _
                ByVal nIndex As Long) _
                As Long

Public Declare Function CallWindowProc Lib "user32" _
                Alias "CallWindowProcA" _
                (ByVal lpPrevWndFunc As Long, _
                ByVal hwnd As Long, _
                ByVal Msg As Long, _
                ByVal wParam As Long, _
                ByVal lParam As Long) _
                As Long
'定義常數
Public Const GWL_WNDPROC = (-4)
Public Const WM_RBUTTONDOWN = &H204
Public Const WM_RBUTTONUP = &H205

'全局變量,存放控件標志性數據
Public preWinProc As Long

'本函數就是用來接收子類時截取的消息的
Public Function wndproc(ByVal hwnd As Long, ByVal Msg As Long, _
                ByVal wParam As Long, ByVal lParam As Long) As Long

    '截取下來的消息存放在msg參數中.
    If (Msg = WM_RBUTTONDOWN) Or (Msg = WM_RBUTTONUP) Then
        '檢測到消息,這里就可以加入處理代碼
        '需要注意,如果這兒不加入任何代碼,則相當于吃掉了這條消息.
    Else
        '如果不是需要處理的消息,則將之送回原來的程序.
        wndproc = CallWindowProc(preWinProc, hwnd, Msg, wParam, lParam)
    End If
End Function