Option Explicit

Public Const WM_USER = &H400

Public Const GWL_WNDPROC = (-4)
Declare Function SetWindowLong Lib "user32" Alias "SetWindowLongA" _
(ByVal hwnd As Long, ByVal nIndex As Long, ByVal dwNewLong As Long) As Long
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
Declare Sub CopyMemory Lib "kernel32" Alias "RtlMoveMemory" _
(hpvDest As Any, hpvSource As Any, ByVal cbCopy As Long)

Public origWndProc As Long
Public Sub SetHook(hwnd, bSet As Boolean)

If bSet Then
origWndProc = SetWindowLong(hwnd, GWL_WNDPROC, AddressOf AppWndProc)
ElseIf origWndProc Then
Dim lRet As Long
lRet = SetWindowLong(hwnd, GWL_WNDPROC, origWndProc)
End If

End Sub
Public Function AppWndProc(ByVal hwnd As Long, ByVal msg As Long, _
ByVal wParam As Long, ByVal lParam As Long) As Long

Select Case msg
Case WM_USER + 1
Select Case LoWord(lParam)
Case FD_READ
Form1.VbRecv hwnd, msg, wParam, lParam
Case FD_CLOSE
Form1.VbClose hwnd, msg, wParam, lParam
Case FD_ACCEPT
Form1.VbAccept hwnd, msg, wParam, lParam
End Select
End Select
AppWndProc = CallWindowProc(origWndProc, hwnd, msg, wParam, lParam)

End Function
Public Function LoWord(ByVal LongIn As Long) As Integer

Call CopyMemory(LoWord, LongIn, 2)

End Function
Public Function HiWord(ByVal LongIn As Long) As Integer

Call CopyMemory(HiWord, ByVal (VarPtr(LongIn) + 2), 2)

End Function 

 

本文来源：http://blog.csdn.net/surro/archive/2007/08/22/1754927.aspx