WINDOWS未公开函数揭密
这次介绍的是如何利用Windows未公开函数实现系统文件操作监视功能。利用该功能可以对Windows下的任何文件操作，包括建立文件、文件夹；删除文件；改变文件大小等操作都可以纪录在案。
首先来介绍实现上面操作的两个未公开函数：SHChangeNotifyRegister和SHChangeNotifyDeregister，SHChangeNotifyRegister函数的定义如下：
Declare Function SHChangeNotifyRegister Lib “shell32" Alias “＃2" _
(ByVal hWnd As Long, _
ByVal uFlags As SHCN_ItemFlags, _
ByVal dwEventID As SHCN_EventIDs,
ByVal uMsg As Long, _
ByVal cItems As Long, _
lpps As PIDLSTRUCT) As Long
其中参数hWnd指定接受系统通告的窗口句柄，参数uMsg指定消息值，如果函数调用成功，系统就会将hWnd指定的窗口加入到系统通告链中，并且返回系统通告句柄。当有建立文件等系统操作发生时，系统会向hWnd指定的窗口发送uMsg消息，关于其它参数，会在下面的程序中说明。函数SHChangeNotifyDeregister的定义如下：
Declare Function SHChange Notify Deregister Lib“shell32" Alias “＃4" _
(ByVal hNotify As Long) As Boolean
其中参数hNotify指定系统通告的句柄。
下面是操作的具体的VB范例：
首先建立一个新的工程，在Form1中加入一个TextBox控件。在Form1的代码窗口之中加入以下代码：
Option Explicit
Private Sub Form_Load()
If SubClass(hWnd) Then '改变Form1的消息处理函数
If IsIDE Then
Text1.Text = vbCrLf ＆ _
“一个 Windows的文件目录操作即时监视程序," ＆ vbCrLf ＆ “可以监视在Explore中的重命名、新建、删除文" ＆ _
vbCrLf ＆ “件或目录；改变文件关联；插入、取出CD和添加“＆ vbCrLf ＆ "删除网络共享都可以被该程序记录下来。"
End If
Call SHNotify_Register(hWnd)
Else
Text1 =“系统不支持操作监视程序 :－)"
End If
Move Screen.Width － Width, Screen.Height － Height
End Sub
Private Function IsIDE() As Boolean
On Error GoTo Out
Debug.Print 1 / 0
Out:
IsIDE = Err
End Function
Private Sub Form_Unload(Cancel As Integer)
Call SHNotify_Unregister
Call UnSubClass(hWnd)
End Sub
Public Sub NotificationReceipt(wParam As Long, lParam As Long)
Dim sOut As String
Dim shns As SHNOTIFYSTRUCT
Dim sDisplayname1 As String
Dim sDisplayname2 As String
MoveMemory shns, ByVal wParam, Len(shns)
If shns.dwItem1 Then
sDisplayname1 = GetDisplayNameFromPIDL(shns.dwItem1)
End If
If shns.dwItem2 Then
sDisplayname2 = GetDisplayNameFromPIDL(shns.dwItem2)
End If
sOut = SHNotify_ GetEvent Str(sDisplayname1, sDisplayname2, lParam) ＆ vbCrLf
Text1 = Text1 ＆ sOut ＆ vbCrLf
Text1.SelStart = Len(Text1)
End Sub
然后在工程中加入三个模块（Bas）文件，将三个文件分别保存为mDef.Bas、mShell.Bas、mSub.Bas。在mDef.Bas中加入以下代码：
'mDef.Bas包含Shell操作的函数和数据类型的定义
Option Explicit
Declare Sub MoveMemory Lib “kernel32" Alias“RtlMoveMemory" (pDest As Any, _
pSource As Any, ByVal dwLength As Long)
Declare Sub CoTaskMemFree Lib “ole32.dll" (ByVal pv As Long)
Public Const MAX_PATH = 260
Public Const NOERROR = 0
'SHGetSpecialFolderLocation获得某一个特殊的目录的位置,如果函数调用成功返回NOERROR
'或者一个OLE错误
Declare Function SHGetSpecialFolderLocation Lib “shell32.dll" _
(ByVal hwndOwner As Long, _
ByVal nFolder As SHSpecialFolderIDs, _
pidl As Long) As Long
Public Enum SHSpecialFolderIDs
'列出所有Windows下特殊文件夹的ID
CSIDL_DESKTOP = ＆H0
CSIDL_INTERNET = ＆H1
CSIDL_PROGRAMS = ＆H2
CSIDL_CONTROLS = ＆H3
CSIDL_PRINTERS = ＆H4
CSIDL_PERSONAL = ＆H5
CSIDL_FAVORITES = ＆H6
CSIDL_STARTUP = ＆H7
CSIDL_RECENT = ＆H8
CSIDL_SENDTO = ＆H9
CSIDL_BITBUCKET = ＆HA
CSIDL_STARTMENU = ＆HB
CSIDL_DESKTOPDIRECTORY = ＆H10
CSIDL_DRIVES = ＆H11
CSIDL_NETWORK = ＆H12
CSIDL_NETHOOD = ＆H13
CSIDL_FONTS = ＆H14
CSIDL_TEMPLATES = ＆H15
CSIDL_COMMON_STARTMENU = ＆H16
CSIDL_COMMON_PROGRAMS = ＆H17
CSIDL_COMMON_STARTUP = ＆H18
CSIDL_COMMON_DESKTOPDIRECTORY = ＆H19
CSIDL_APPDATA = ＆H1A
CSIDL_PRINTHOOD = ＆H1B
CSIDL_ALTSTARTUP = ＆H1D
CSIDL_COMMON_ALTSTARTUP = ＆H1E
CSIDL_COMMON_FAVORITES = ＆H1F
CSIDL_INTERNET_CACHE = ＆H20
CSIDL_COOKIES = ＆H21
CSIDL_HISTORY = ＆H22
End Enum
'SHGetPathFromIDList函数将一个Item转换为文件路径
Declare Function SHGetPathFromIDList Lib“shell32.dll" Alias “SHGetPathFromIDListA" _
(ByVal pidl As Long, _
ByVal pszPath As String) As Long
'SHGetFileInfoPidl函数获得某个文件对象的信息。
Declare Function SHGetFileInfoPidl Lib “shell32" Alias“SHGetFileInfoA" (ByVal pidl As Long, _
ByVal dwFileAttributes As Long, _
psfib As SHFILEINFOBYTE, _
ByVal cbFileInfo As Long, _
ByVal uFlags As SHGFI_flags) As Long
Public Type SHFILEINFOBYTE
hIcon As Long
iIcon As Long
dwAttributes As Long
szDisplayName(1 To MAX_PATH) As Byte
szTypeName(1 To 80) As Byte
End Type
Declare Function SHGetFileInfo Lib “shell32" Alias “SHGetFileInfoA" _
(ByVal pszPath As String, _
ByVal dwFileAttributes As Long, _
psfi As SHFILEINFO, _
ByVal cbFileInfo As Long, _
ByVal uFlags As SHGFI_flags) As Long
Public Type SHFILEINFO
hIcon As Long
iIcon As Long
dwAttributes As Long
szDisplayName As String ＊ MAX_PATH
szTypeName As String ＊ 80
End Type
Enum SHGFI_flags
SHGFI_LARGEICON = ＆H0
SHGFI_SMALLICON = ＆H1
SHGFI_OPENICON = ＆H2
SHGFI_SHELLICONSIZE = ＆H4
SHGFI_PIDL = ＆H8
SHGFI_USEFILEATTRIBUTES = ＆H10
SHGFI_ICON = ＆H100
SHGFI_DISPLAYNAME = ＆H200
SHGFI_TYPENAME = ＆H400
SHGFI_ATTRIBUTES = ＆H800
SHGFI_ICONLOCATION = ＆H1000
SHGFI_EXETYPE = ＆H2000
SHGFI_SYSICONINDEX = ＆H4000
SHGFI_LINKOVERLAY = ＆H8000
SHGFI_SELECTED = ＆H10000
End Enum
