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首页 - 经验之谈 - Windows未公开函数揭密——之三
发表评论(0)作者:发条桔子, 平台:VB6.0+Win98, 阅读:9500, 日期:2001-03-11
Windows未公开函数揭密——之三

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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 SHChangeNotifyDeregister 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  注释: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_GetEventStr(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:
注释: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

注释: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
注释: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      注释: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

注释: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

注释: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

注释:根据一个特定文件夹对象的ID获得它的目录pidl
Public Function GetPIDLFromFolderID(hOwner As Long, nFolder As SHSpecialFolderIDs) As Long
    Dim pidl As Long
    If SHGetSpecialFolderLocation(hOwner, nFolder, pidl) = NOERROR Then
        GetPIDLFromFolderID = pidl
    End If
End Function

Public Function GetDisplayNameFromPIDL(pidl As Long) As String
    Dim sfib As SHFILEINFOBYTE
    If SHGetFileInfoPidl(pidl, 0, sfib, Len(sfib), SHGFI_PIDL Or SHGFI_DISPLAYNAME) Then
        GetDisplayNameFromPIDL = GetStrFromBufferA(StrConv(sfib.szDisplayName, vbUnicode))
    End If
End Function

Public Function GetPathFromPIDL(pidl As Long) As String
    Dim sPath As String * MAX_PATH
    If SHGetPathFromIDList(pidl, sPath) Then
        GetPathFromPIDL = GetStrFromBufferA(sPath)
    End If
End Function

Public Function GetStrFromBufferA(sz As String) As String
    If InStr(sz, vbNullChar) Then
        GetStrFromBufferA = Left$(sz, InStr(sz, vbNullChar) - 1)
    Else
        GetStrFromBufferA = sz
    End If
End Function

在mShell.Bas中加入以下代码:
注释:mShell.Bas函数包含注册和反注册系统通告以及文件夹信息转换的函数
Option Explicit

Private m_hSHNotify As Long     注释:系统消息通告句柄
Private m_pidlDesktop As Long

注释:定义系统通告的消息值
Public Const WM_SHNOTIFY = &H401

Public Type PIDLSTRUCT
    pidl As Long
    bWatchSubFolders As Long
End Type

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

Type SHNOTIFYSTRUCT
    dwItem1 As Long
    dwItem2 As Long
End Type

Declare Function SHChangeNotifyDeregister Lib "shell32" Alias "#4" _
        (ByVal hNotify As Long) As Boolean

Declare Sub SHChangeNotify Lib "shell32" _
                        (ByVal wEventId As SHCN_EventIDs, _
                        ByVal uFlags As SHCN_ItemFlags, _
                        ByVal dwItem1 As Long, _
                        ByVal dwItem2 As Long)

Public Enum SHCN_EventIDs
    SHCNE_RENAMEITEM = &H1
    SHCNE_CREATE = &H2
    SHCNE_DELETE = &H4
    SHCNE_MKDIR = &H8
    SHCNE_RMDIR = &H10
    SHCNE_MEDIAINSERTED = &H20
    SHCNE_MEDIAREMOVED = &H40
    SHCNE_DRIVEREMOVED = &H80
    SHCNE_DRIVEADD = &H100
    SHCNE_NETSHARE = &H200
    SHCNE_NETUNSHARE = &H400
    SHCNE_ATTRIBUTES = &H800
    SHCNE_UPDATEDIR = &H1000
    SHCNE_UPDATEITEM = &H2000
    SHCNE_SERVERDISCONNECT = &H4000
    SHCNE_UPDATEIMAGE = &H8000&
    SHCNE_DRIVEADDGUI = &H10000
    SHCNE_RENAMEFOLDER = &H20000
    SHCNE_FREESPACE = &H40000
    SHCNE_ASSOCCHANGED = &H8000000

    SHCNE_DISKEVENTS = &H2381F
    SHCNE_GLOBALEVENTS = &HC0581E0
    SHCNE_ALLEVENTS = &H7FFFFFFF
    SHCNE_INTERRUPT = &H80000000
End Enum

#If (WIN32_IE >= &H400) Then
    Public Const SHCNEE_ORDERCHANGED = &H2
#End If

Public Enum SHCN_ItemFlags
    SHCNF_IDLIST = &H0
    SHCNF_PATHA = &H1
    SHCNF_PRINTERA = &H2
    SHCNF_DWORD = &H3
    SHCNF_PATHW = &H5
    SHCNF_PRINTERW = &H6
    SHCNF_TYPE = &HFF
    SHCNF_FLUSH = &H1000
    SHCNF_FLUSHNOWAIT = &H2000

    #If UNICODE Then
        SHCNF_PATH = SHCNF_PATHW
        SHCNF_PRINTER = SHCNF_PRINTERW
    #Else
        SHCNF_PATH = SHCNF_PATHA
        SHCNF_PRINTER = SHCNF_PRINTERA
    #End If
End Enum

Public Function SHNotify_Register(hWnd As Long) As Boolean
    Dim ps As PIDLSTRUCT
  
    If (m_hSHNotify = 0) Then
  
        m_pidlDesktop = GetPIDLFromFolderID(0, CSIDL_DESKTOP)
        If m_pidlDesktop Then
      
            ps.pidl = m_pidlDesktop
            ps.bWatchSubFolders = True
      
            注释:注册Windows监视,将获得的句柄保存到m_hSHNotify中
            m_hSHNotify = SHChangeNotifyRegister(hWnd, SHCNF_TYPE Or SHCNF_IDLIST, _
                                            SHCNE_ALLEVENTS Or SHCNE_INTERRUPT, _
                                            WM_SHNOTIFY, 1, ps)
            SHNotify_Register = CBool(m_hSHNotify)
    
        Else
            Call CoTaskMemFree(m_pidlDesktop)
        End If
    End If
End Function

Public Function SHNotify_Unregister() As Boolean
    If m_hSHNotify Then
        If SHChangeNotifyDeregister(m_hSHNotify) Then
            m_hSHNotify = 0
            Call CoTaskMemFree(m_pidlDesktop)
            m_pidlDesktop = 0
            SHNotify_Unregister = True
        End If
    End If
End Function

Public Function SHNotify_GetEventStr(strPath1, strPath2 As String, dwEventID As Long) As String
    Dim sEvent As String
    
    Select Case dwEventID
        Case SHCNE_RENAMEITEM: sEvent = "重命名文件" + strPath1 + "为" + strPath2
        Case SHCNE_CREATE: sEvent = "建立文件 文件名:" + strPath1
        Case SHCNE_DELETE: sEvent = "删除文件 文件名:" + strPath1
        Case SHCNE_MKDIR: sEvent = "新建目录 目录名:" + strPath1
        Case SHCNE_RMDIR: sEvent = "删除目录 目录名:" + strPath1
        Case SHCNE_MEDIAINSERTED: sEvent = strPath1 + "中插入可移动存储介质"
        Case SHCNE_MEDIAREMOVED: sEvent = strPath1 + "中移去可移动存储介质"
        Case SHCNE_DRIVEREMOVED: sEvent = "移去驱动器" + strPath1
        Case SHCNE_DRIVEADD: sEvent = "添加驱动器" + strPath1
        Case SHCNE_NETSHARE: sEvent = "改变目录" + strPath1 + "的共享属性"
        Case SHCNE_UPDATEDIR: sEvent = "更新目录" + strPath1
        Case SHCNE_UPDATEITEM: sEvent = "更新文件 文件名:" + strPath1
        Case SHCNE_SERVERDISCONNECT: sEvent = "断开与服务器的连" + strPath1 + "  " + strPath2
        Case SHCNE_UPDATEIMAGE: sEvent = "SHCNE_UPDATEIMAGE"
        Case SHCNE_DRIVEADDGUI: sEvent = "SHCNE_DRIVEADDGUI"
        Case SHCNE_RENAMEFOLDER: sEvent = "重命名文件夹" + strPath1 + "为" + strPath2
        Case SHCNE_FREESPACE: sEvent = "磁盘空间大小改变"
    
        Case SHCNE_ASSOCCHANGED: sEvent = "改变文件关联"
    End Select
  
    SHNotify_GetEventStr = sEvent
End Function

在mSub.Bas中加入以下代码:
注释:mSub函数包括窗口的消息处理函数
Option Explicit

Private Const WM_NCDESTROY = &H82
Private Const GWL_WNDPROC = (-4)
Private Const OLDWNDPROC = "OldWndProc"

Private Declare Function GetProp Lib "user32" Alias "GetPropA" (ByVal _
        hWnd As Long, ByVal lpString As String) As Long
Private Declare Function SetProp Lib "user32" Alias "SetPropA" (ByVal _
        hWnd As Long, ByVal lpString As String, ByVal hData As Long) As Long
Private Declare Function RemoveProp Lib "user32" Alias "RemovePropA" (ByVal _
        hWnd As Long, ByVal lpString As String) As Long

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

Private Declare Function CallWindowProc Lib "user32" Alias "CallWindowProcA" _
        (ByVal lpPrevWndFunc As Long, ByVal hWnd As Long, ByVal uMsg As Long, _
        ByVal wParam As Long, ByVal lParam As Long) As Long

Public Function SubClass(hWnd As Long) As Boolean
    Dim lpfnOld As Long
    Dim fSuccess As Boolean
  
    If (GetProp(hWnd, OLDWNDPROC) = 0) Then
        lpfnOld = SetWindowLong(hWnd, GWL_WNDPROC, AddressOf WndProc)
        If lpfnOld Then
            fSuccess = SetProp(hWnd, OLDWNDPROC, lpfnOld)
        End If
    End If
  
    If fSuccess Then
        SubClass = True
    Else
        If lpfnOld Then Call UnSubClass(hWnd)
        MsgBox "Unable to successfully subclass &H" & Hex(hWnd), vbCritical
    End If
End Function

Public Function UnSubClass(hWnd As Long) As Boolean
    Dim lpfnOld As Long
  
    lpfnOld = GetProp(hWnd, OLDWNDPROC)
    If lpfnOld Then
        If RemoveProp(hWnd, OLDWNDPROC) Then
            UnSubClass = SetWindowLong(hWnd, GWL_WNDPROC, lpfnOld)
        End If
    End If
End Function

Public Function WndProc(ByVal hWnd As Long, ByVal uMsg As Long, ByVal wParam As _
        Long, ByVal lParam As Long) As Long
    Select Case uMsg
        Case WM_SHNOTIFY        注释:处理系统消息通告函数
            Call Form1.NotificationReceipt(wParam, lParam)
        Case WM_NCDESTROY
            Call UnSubClass(hWnd)
            MsgBox "Unubclassed &H" & Hex(hWnd), vbCritical, "WndProc Error"
    End Select
    
    WndProc = CallWindowProc(GetProp(hWnd, OLDWNDPROC), hWnd, uMsg, wParam, lParam)
End Function

保存文件,然后运行程序,然后你可以在Explore中试着建立或者删除一个文件或者文件夹,在Form中可以看到你所做的操作已经被纪录并且显示到TextBox中了。
现在分析以下上面的程序,上面的程序首先调用SHChangeNotifyRegister函数将Form添加到系统消息通告链中,并利用SetWindowLong函数改变Form的缺省的消息处理函数,当接受到系统通告消息后,根据传递的参数获得系统通告的内容并且显示在文本窗口中。退出程序时调用SHChangeNotifyDeregister函数注销系统消息通告。