如何判断文件或文件夹是否存在??

if dir("c:\boot.ini")="" then
不存在
else
存在
end if

用DIR函数这个问题我刚问过
http://expert.csdn.net/Expert/topic/1471/1471690.xml?temp=.6334955
这个帖子对你一定有帮助的

判断文件是否存在：if dir(filename,vbNormal)=vbnullstring then '判断文件是否存在；
判断文件是否存在：if dir(filename,vbDirectory)=vbnullstring then '判断文件夹是否存在；

如果不支持长路径，可以参考这个
Place this code in a .bas moduleOption ExplicitPublic Declare Function GetShortPathName Lib "kernel32" _
    Alias "GetShortPathNameA" _
    (ByVal lpszLongPath As String, _
    ByVal lpszShortPath As String, _
    ByVal cchBuffer As Long) As LongPublic Function GetShortName(sFile As String) As String
    Dim sShortFile As String * 67
    Dim lResult As Long    'Make a call to the GetShortPathName API
    lResult = GetShortPathName(sFile, sShortFile, _
    Len(sShortFile))    'Trim out unused characters from the string.
    GetShortName = Left$(sShortFile, lResult)End Function
'--end code block
Now place this code in the Form_Load eventPrivate Sub Form_Load()    Debug.Print GetShortName(App.Path)End Sub

那么怎样判断
文件:"%ProgramFiles%\Windows NT\Accessories\WORDPAD.EXE"
是否存在呢?

但是好像不能判断
文件:"%ProgramFiles%\Windows NT\Accessories\WORDPAD.EXE"
这种文件路径.怎么办?难道要先读取所有系统路径,然后不停的case 吗? 有更好的办法吗?

试试这个,我一直用,也很好呀.一个VB资源盘上的不是我自己的东东
Function FileExists(ByVal Filename As String) As Integer
Dim Temp$    'Set Default
    FileExists = True

    'Set up error handler
On Error Resume Next    'Attempt to grab date and time
    Temp$ = FileDateTime(Filename)    'Process errors
    Select Case Err
        Case 53, 76, 68   'File Does Not Exist
            FileExists = False
            Err = 0
        Case Else
            If Err <> 0 Then
             FileExists = False
             Err = 0
          End If
    End Select
End Function

我不是为了要你给分,真是希望我能帮你什么,下面是我收集和自己写的一些文件处理函数.
Option ExplicitFunction FileExists(ByVal Filename As String) As Integer
Dim Temp$    'Set Default
    FileExists = True

    'Set up error handler
On Error Resume Next    'Attempt to grab date and time
    Temp$ = FileDateTime(Filename)    'Process errors
    Select Case Err
        Case 53, 76, 68   'File Does Not Exist
            FileExists = False
            Err = 0
        Case Else
            If Err <> 0 Then
             FileExists = False
             Err = 0
          End If
    End Select
End FunctionFunction AddPathToFile(ByVal sPathIn As String, ByVal sFileNameIn As String) As String
'*******************************************************************
'
'  PURPOSE: Takes a path (including Drive letter and any subdirs) and
'           concatenates the file name to path. Path may be empty, path
'           may or may not have an ending backslash '\'.  No validation
'           or existance is check on path or file.
'
'  INPUTS:  sPathIn - Path to use
'           sFileNameIn - Filename to use
'
'
'  OUTPUTS:  N/A
'
'  RETURNS:  Path concatenated to File.
'
'*******************************************************************
Dim sPath As String
Dim sFileName As String
    'Remove any leading or trailing spaces
    sPath = Trim$(sPathIn)
    sFileName = Trim$(sFileNameIn)    If sPath = "" Then
       AddPathToFile = sFileName
    Else
       If Right$(sPath, 1) = "\" Then
         AddPathToFile = sPath & sFileName
       Else
         AddPathToFile = sPath & "\" & sFileName
       End If
    End IfEnd FunctionFunction ExtractFileName(sFileName As Variant) As String
'*******************************************************************
'
'  PURPOSE: This returns just a file name from a full/partial path.
'
'  INPUTS:  sFileName - String Data to remove path from.
'
'  OUTPUTS: N/A
'
'  RETURNS: This function returns all the characters from right to the
'           first \.  Does NOT check validity of the filename....
'
'*******************************************************************
Dim nIdx As Integer    If Right(Trim(sFileName), 1) = "\" Then
    ExtractFileName = ""
    Else    For nIdx = Len(sFileName) To 1 Step -1
        If Mid$(sFileName, nIdx, 1) = "\" Then
            ExtractFileName = Mid$(sFileName, nIdx + 1)
            Exit Function
        End If
    Next nIdx    ExtractFileName = sFileName
    End If
End FunctionFunction ExtractPath(sFileName) As String
'*******************************************************************
'
'  PURPOSE: This returns just a path name from a full/partial path.
'
'  INPUTS:  sFileName - String Data to remove file from.
'
'  OUTPUTS: N/A
'
'  RETURNS: This function returns all the characters from left to the last
'           first \.  Does NOT check validity of the filename/Path....
'*******************************************************************
Dim nIdx As Integer
    For nIdx = Len(sFileName) To 1 Step -1
       If Mid$(sFileName, nIdx, 1) = "\" Then
          ExtractPath = Mid$(sFileName, 1, nIdx)
          Exit Function
       End If
    Next nIdx

    ExtractPath = sFileNameEnd Function
'提取命令行文件名
Public Function ExtractCommandFiles(sFileName As String, xFilename() As String) As Integer
If sFileName = "" Then
ExtractCommandFiles = 0
Else
ReDim Preserve xFilename(0)
Dim FlagStart As Boolean '是否是"号的开始
Dim Slen As Integer '字符串参数长度
Dim ai As Integer '数组开始序号
Dim CString As String '每次提取的字符
FlagStart = True
Slen = Len(sFileName)
ai = 0
Dim i As Integer
For i = 1 To Slen
CString = Mid(sFileName, i, 1)
Select Case CString
Case Chr(32) '空格
If FlagStart Then
  If Not Trim(xFilename(ai)) = "" Then
    ai = ai + 1
    ReDim Preserve xFilename(ai)
  End If
Else
    xFilename(ai) = xFilename(ai) + CString
End If
  '    FlagStart = Not FlagStart

Case Chr(34) ' "号
    If FlagStart Then
        If Not Trim(xFilename(ai)) = "" Then
        ai = ai + 1
        ReDim Preserve xFilename(ai)
        End If
    End If
       FlagStart = Not FlagStart

Case Else    xFilename(ai) = xFilename(ai) + CString
End Select
Next i
ExtractCommandFiles = ai + 1
End If
End Function
'判断是文件还是目录
Private Declare Function GetFileAttributes Lib "kernel32" Alias _
    "GetFileAttributesA" (ByVal lpFileName As String) As LongPrivate Const FILE_ATTRIBUTE_READONLY = &H1
Private Const FILE_ATTRIBUTE_HIDE = &H2
Private Const FILE_ATTRIBUTE_ARCHIVE = &H20
Private Const FILE_ATTRIBUTE_SYSTEM = &H4
Private Const FILE_ATTRIBUTE_DIRECTORY = &H10
Private Const FILE_ATTRIBUTE_NORMAL = &H80Private Function IsFile(sFile As String) As FileProp '判断文件属性
        IsFile.ReadOnly = (GetFileAttributes(sFile) And _
        FILE_ATTRIBUTE_READONLY)        IsFile.Hide = (GetFileAttributes(sFile) And _
        FILE_ATTRIBUTE_HIDE)        IsFile.Archive = (GetFileAttributes(sFile) And _
        FILE_ATTRIBUTE_ARCHIVE)
        IsFile.System = (GetFileAttributes(sFile) And _
        FILE_ATTRIBUTE_SYSTEM)        IsFile.IsFile = (GetFileAttributes(sFile) And _
            FILE_ATTRIBUTE_DIRECTORY)
        IsFile.IsFile = Not IsFile.IsFile
End Function

这是我写的一个判断文件是否存在的一个函数
Function reportfilestatus(filespec) As Boolean
'Dim fso, msg
Set fso = CreateObject("scripting.filesystemobject")
If (fso.FileExists(filespec)) Then
reportfilestatus = True
Else
reportfilestatus = False
End If
End Function

Dim oFileSys As FileSystemObjectSet oFileSys = New FileSystemObject'文件甲
If oFileSys.FolderExists("C:\Windows\") = False Then
'不存在
End If
'文件
If objFileSys.FileExists(FileName) = False Then
'不存在
End If

使用Win32API OpenFile(),检查文件是绝对可以，文件夹我没试过，你自己试一下。代码最好放在公共模块中，如下
'================= Win32 API and CONSTANTS for API =================='for File operation
Public Declare Function OpenFile Lib "kernel32" (ByVal lpFileName As String, lpReOpenBuff As OFSTRUCT, ByVal wStyle As Long) As Long
Public Const OF_EXIST = &H4000
Public Const OFS_MAXPATHNAME = 128
Public Type OFSTRUCT
        cBytes                      As Byte
        fFixedDisk                  As Byte
        nErrCode                    As Integer
        Reserved1                   As Integer
        Reserved2                   As Integer
        szPathName(OFS_MAXPATHNAME) As Byte
End TypePublic Function FileExists(ByVal sFilename As String) As Boolean
'----------------------------
'*** function: FileExists()
'*** Abstract: Check if the file exists
'*** Return : True - file exists,False - file not exists
'created on 2002-07-17 ,zdleek
'----------------------------Dim udtOFStruct As OFSTRUCT

On Error GoTo CheckErr
    FileExists = False
    If Len(sFilename) > 0 Then
        OpenFile sFilename, udtOFStruct, OF_EXIST
        FileExists = udtOFStruct.nErrCode <> 2
    End If

Exit FunctionCheckErr:
    FileExists = False

End Function

"%ProgramFiles%\Windows NT\Accessories\WORDPAD.EXE"
试试看：
Environ("ProgramFiles") & "\Windows NT\Accessories\WORDPAD.EXE"

Dir[(pathname[, attributes])]Dir 函数的语法具有以下几个部分：部分描述
pathname 可选参数。用来指定文件名的字符串表达式，可能包含目录或文件夹、以及驱动器。如果没有找到 pathname，则会返回零长度字符串 ("")。
attributes 可选参数。常数或数值表达式，其总和用来指定文件属性。如果省略，则会返回匹配 pathname 但不包含属性的文件。
设置值attributes 参数的设置可为：常数值描述
vbNormal 0 (缺省) 指定没有属性的文件。
vbReadOnly 1 指定无属性的只读文件
vbHidden 2 指定无属性的隐藏文件
VbSystem 4 指定无属性的系统文件
vbVolume 8 指定卷标文件；如果指定了其它属性，则忽略vbVolume
vbDirectory 16 指定无属性文件及其路径和文件夹。

用dir 命令
if dir("c:\boot.ini")="" then
不存在
else
存在
end if

%ProgramFiles%:先得到Windows路径（帖子有的是）
%ProgramFiles%=left(winpath,3) & "Program Files\"

Dir 函数示例
本示例使用 Dir 函数来检查某些文件或目录是否存在。在 Macintosh 计算机上，默认驱动器名称是 “HD” ，并且路径部分由冒号取代反斜线隔开。而且 Microsoft Windows 的通配符在 Mac 中可以作为有效字符出现在文件名中。也可以使用 MacID 函数来指定文件组。Dim MyFile, MyPath, MyName' 返回“WIN.INI” （如果该文件存在）。
MyFile = Dir("C:\WINDOWS\WIN.ini")   ' 返回带指定扩展名的文件名。如果超过一个 *.ini 文件存在，
' 函数将返回按条件第一个找到的文件名。
MyFile = Dir("C:\WINDOWS\*.ini")' 若第二次调用 Dir 函数，但不带任何参数，则函数将返回同一目录下的下一个 *.ini 文件。
MyFile = Dir' 返回找到的第一个隐式 *.TXT 文件。
MyFile = Dir("*.TXT", vbHidden)' 显示 C:\ 目录下的名称。
MyPath = "c:\"   ' 指定路径。
MyName = Dir(MyPath, vbDirectory)   ' 找寻第一项。
Do While MyName <> ""   ' 开始循环。
   ' 跳过当前的目录及上层目录。
   If MyName <> "." And MyName <> ".." Then
      ' 使用位比较来确定 MyName 代表一目录。
      If (GetAttr(MyPath & MyName) And vbDirectory) = vbDirectory Then
         Debug.Print MyName   ' 如果它是一个目录，将其名称显示出来。
      End If
   End If
   MyName = Dir   ' 查找下一个目录。
Loop

调试易

如何判断文件或文件夹是否存在??

解决方案 »