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主题:VB与Windows资源管理器互拷文件

作者:长沙 陈锐



   通过VB编程来拷贝或移动文件的原理可能大家都十分清楚,可以利用Windows APISHFileOperation来进行操作,也可以利用VB内置的函数来操作。但是利用这些方法编写的程序只能在程序内部执行文件的操作。这里我要向大家介绍如何通过VB编程将程序中的文件操作同Windows的资源管理器中的拷贝、剪切操作连接起来。

   在Windows的资源管理器中,选中一个或多个文件,在文件上单击鼠标右键,在弹出菜单中选复制。再切换到另外的目录,单击鼠标右键,点粘贴。就这样执行了一次文件的拷贝操作,那么Windows在拷贝过程中执行了什么操作,是否将整个文件拷贝到剪贴板上了呢?当然没有。实际上,Windows只是将一个文件结构拷贝到了剪贴版,这个结构如下:

   tDropFile+文件1文件名+vbNullChar+文件2文件名+vbNullChar……+文件N文件名+vbNullChar,其中tDropFile是一个DROPFILES结构,这个结构在Windows API中有定义。在粘贴文件时,利用API函数 DragQueryFile 就可以获得拷贝到剪贴板的文件全路径名,然后就可以根据获得的文件名执行文件拷贝函数,实现对文件的粘贴操作。

   下面通过具体的程序来介绍:

   1、在工程文件中加入一个Module,然后在Module中加入如下代码:

  Option Explicit

  Private Type POINTAPI

   x As Long

   y As Long

  End Type

  Private Type SHFILEOPSTRUCT

   hwnd As Long

   wFunc As Long

   pFrom As String

   pTo As String

   fFlags As Integer

   fAnyOperationsAborted As Long

   hNameMappings As Long

   lpszProgressTitle As String

  End Type

  Private Declare Function SHFileOperation Lib “shell32.dll" Alias _

   “SHFileOperationA" (lpFileOp As SHFILEOPSTRUCT) As Long

  '剪贴板处理函数

  Private Declare Function EmptyClipboard Lib “user32" () As Long

  Private Declare Function OpenClipboard Lib “user32" (ByVal hwnd _

   As Long) As Long

  Private Declare Function CloseClipboard Lib “user32" () As Long

  Private Declare Function SetClipboardData Lib “user32" (ByVal wFormat _

   As Long, ByVal hMem As Long) As Long

  Private Declare Function GetClipboardData Lib “user32" (ByVal wFormat _

   As Long) As Long

  Private Declare Function IsClipboardFormatAvailable Lib “user32" _

   (ByVal wFormat As Long) As Long

  Private Declare Function DragQueryFile Lib “shell32.dll" Alias _

   “DragQueryFileA" (ByVal hDrop As Long, ByVal UINT As Long, _

   ByVal lpStr As String, ByVal ch As Long) As Long

  Private Declare Function DragQueryPoint Lib “shell32.dll" (ByVal _

   hDrop As Long, lpPoint As POINTAPI) As Long

  Private Declare Function GlobalAlloc Lib “kernel32" (ByVal wFlags _

   As Long, ByVal dwBytes As Long) As Long

  Private Declare Function GlobalFree Lib “kernel32" (ByVal hMem As _

   Long) As Long

  Private Declare Function GlobalLock Lib “kernel32" (ByVal hMem As _

   Long) As Long

  Private Declare Function GlobalUnlock Lib “kernel32" (ByVal hMem As _

   Long) As Long

  Private Declare Sub CopyMem Lib“kernel32" Alias “RtlMoveMemory" _

   (Destination As Any, Source As Any, ByVal Length As Long)

  '剪贴板数据格式定义

  Private Const CF_TEXT = 1

  Private Const CF_BITMAP = 2

  Private Const CF_METAFILEPICT = 3

  Private Const CF_SYLK = 4

  Private Const CF_DIF = 5

  Private Const CF_TIFF = 6

  Private Const CF_OEMTEXT = 7

  Private Const CF_DIB = 8

  Private Const CF_PALETTE = 9

  Private Const CF_PENDATA = 10

  Private Const CF_RIFF = 11

  Private Const CF_WAVE = 12

  Private Const CF_UNICODETEXT = 13

  Private Const CF_ENHMETAFILE = 14

  Private Const CF_HDROP = 15

  Private Const CF_LOCALE = 16

  Private Const CF_MAX = 17

  ' 内存操作定义

  Private Const GMEM_FIXED = &H0

  Private Const GMEM_MOVEABLE = &H2

  Private Const GMEM_NOCOMPACT = &H10

  Private Const GMEM_NODISCARD = &H20

  Private Const GMEM_ZEROINIT = &H40

  Private Const GMEM_MODIFY = &H80

  Private Const GMEM_DISCARDABLE = &H100

  Private Const GMEM_NOT_BANKED = &H1000

  Private Const GMEM_SHARE = &H2000

  Private Const GMEM_DDESHARE = &H2000

  Private Const GMEM_NOTIFY = &H4000

  Private Const GMEM_LOWER = GMEM_NOT_BANKED

  Private Const GMEM_VALID_FLAGS = &H7F72

  Private Const GMEM_INVALID_HANDLE = &H8000

  Private Const GHND = (GMEM_MOVEABLE Or GMEM_ZEROINIT)

  Private Const GPTR = (GMEM_FIXED Or GMEM_ZEROINIT)

  Private Const FO_COPY = &H2

  Private Type DROPFILES

   pFiles As Long

   pt As POINTAPI

   fNC As Long

   fWide As Long

  End Type

  Public Function clipCopyFiles(Files() As String) As Boolean

   Dim data As String

   Dim df As DROPFILES

   Dim hGlobal As Long

   Dim lpGlobal As Long

   Dim i As Long

   '清除剪贴板中现存的数据

   If OpenClipboard(0&) Then

   Call EmptyClipboard

   For i = LBound(Files) To UBound(Files)

   data = data & Files(i) & vbNullChar

   Next i

   data = data & vbNullChar

   '为剪贴板拷贝操作分配相应大小的内存

   hGlobal = GlobalAlloc(GHND, Len(df) + Len(data))

   If hGlobal Then

   lpGlobal = GlobalLock(hGlobal)

   df.pFiles = Len(df)

   '将DropFiles结构拷贝到内存中

   Call CopyMem(ByVal lpGlobal, df, Len(df))

   '将文件全路径名拷贝到分配的内存中。

   Call CopyMem(ByVal (lpGlobal + Len(df)), ByVal data, _

   Len(data))

   Call GlobalUnlock(hGlobal)

   '将数据拷贝到剪贴板上

   If SetClipboardData(CF_HDROP, hGlobal) Then

   clipCopyFiles = True

   End If

   End If

   Call CloseClipboard

   End If

  End Function

  Public Function clipPasteFiles(Files() As String) As Long

   Dim hDrop As Long

   Dim nFiles As Long

   Dim i As Long

   Dim desc As String

   Dim filename As String

   Dim pt As POINTAPI

   Dim tfStr As SHFILEOPSTRUCT

   Const MAX_PATH As Long = 260

   '确定剪贴板的数据格式是文件,并打开剪贴板

   If IsClipboardFormatAvailable(CF_HDROP) Then

   If OpenClipboard(0&) Then

   hDrop = GetClipboardData(CF_HDROP)

   '获得文件数

   nFiles = DragQueryFile(hDrop, -1&, “", 0)

   ReDim Files(0 To nFiles - 1) As String

   filename = Space(MAX_PATH)

   '确定执行的操作类型为拷贝操作

   tfStr.wFunc = FO_COPY

   '目的路径设置为File1指定的路径

   tfStr.pTo = Form1.File1.Path

   For i = 0 To nFiles - 1

   '根据获取的每一个文件执行文件拷贝操作

   Call DragQueryFile(hDrop, i, filename, Len(filename))

   Files(i) = TrimNull(filename)

   tfStr.pFrom = Files(i)

   SHFileOperation tfStr

   Next i

   Form1.File1.Refresh

   Form1.Dir1.Refresh

   Call CloseClipboard

   End If

   clipPasteFiles = nFiles

   End If

  End Function

  Private Function TrimNull(ByVal StrIn As String) As String

   Dim nul As Long

   nul = InStr(StrIn, vbNullChar)

   Select Case nul

   Case Is > 1

   TrimNull = Left(StrIn, nul - 1)

   Case 1

   TrimNull = “"

   Case 0

   TrimNull = Trim(StrIn)

   End Select

  End Function

   2、在Form1中加入一个FileListBox,Name属性设置为File1。加入一个DirListBox,Name属性设置为Dir1,在Dir1的Change事件中加入如下代码:

  Private Sub Dir1_Change()

  File1.Path = Dir1.Path

  End Sub

  加入一个DriveListBox,Name属性设置为Drive1,在Drive1的Change事件中加入如下代码:

  Private Sub Drive1_Change()

  Dir1.Path = Drive1.Drive

  End Sub

  加入一个CommandButton,Name属性设置为cmdCopy,在cmdCopy的Click事件中加入如下代码:

  Private Sub cmdCopy_Click()

   Dim Files() As String

   Dim Path As String

   Dim i As Long, n As Long

   Path = Dir1.Path

   If Right(Path, 1) <> “\" Then

   Path = Path & “\"

   End If

   '根据在List1上的选择建立拷贝文件的列表

   With File1

   For i = 0 To .ListCount - 1

   If .Selected(i) Then

   ReDim Preserve Files(0 To n) As String

   Files(n) = Path & .List(i)

   n = n + 1

   End If

   Next i

   End With

   '拷贝文件到Clipboard

   If clipCopyFiles(Files) Then

   MsgBox “拷贝文件成功.", , “Success"

   Else

   MsgBox “无法拷贝文件……", , “Failure"

   End If

  End Sub

  加入一个CommandButton,Name属性设置为cmdPaste,在cmdPaste的Click事件中加入如

  下代码:

  Private Sub cmdPaste_Click()

   Dim Files() As String

   Dim nRet As Long

   Dim i As Long

   Dim msg As String

   nRet = clipPasteFiles(Files)

   If nRet Then

   For i = 0 To nRet - 1

   msg = msg & Files(i) & vbCrLf

   Next i

   MsgBox msg, , “共粘贴" & nRet & “个文件"

   Else

   MsgBox“从剪贴版粘贴文件错误", , “Failure"

   End If

  End Sub

  运行文件,在Windows 资源管理器中,选择文件,再在资源管理器菜单中选 编辑 | 复制然后在Form1中点击cmdPaste,从资源管理器中复制的文件就拷贝到Dir1所在的目录中。从File1中选择文件,按cmdCopy复制,再在资源管理器中选 编辑 | 粘贴 ,选择的文件就被拷贝到Windows 资源管理器的当前目录下。

  上面的程序在Windows98 VB6.0下运行通过。