Laufwerk, Ordner, Datei vorhanden ??

[eknori]

In diesem Tip möchte ich euch vorstellen, wie man unter Zuhilfenahme einiger Windows API Calls ermittelt, ob ein Laufwerk, ein Ordner oder eine Datei existiert.

wie immer gibt es den abgedruckten Quelltext auch unter

http://www.eknori.de/downloads/DriveFolderFileExist.zip

Const INVALID_HANDLE_VALUE = -1
Const MAX_PATH = 260
Const FILE_ATTRIBUTE_DIRECTORY = &H10

Type FILETIME
     dwLowDateTime As Long
     dwHighDateTime As Long
End Type

Type WIN32_FIND_DATA
     dwFileAttributes As Long
     ftCreationTime As FILETIME
     ftLastAccessTime As FILETIME
     ftLastWriteTime As FILETIME
     nFileSizeHigh As Long
     nFileSizeLow As Long
     dwReserved0 As Long
     dwReserved1 As Long
     cFileName As String * MAX_PATH
     cAlternate As String * 14
End Type

Declare Function FindFirstFile Lib "kernel32" Alias "FindFirstFileA" (Byval lpFileName As String, lpFindFileData As WIN32_FIND_DATA) As Long
Declare Function FindClose Lib "kernel32" (Byval hFindFile As Long) As Long
Declare Function GetLogicalDriveStrings Lib "kernel32" Alias "GetLogicalDriveStringsA" (Byval nBufferLength As Long, Byval lpBuffer As String) As Long


Sub Click(Source As Button)
     Msgbox DriveExists("Z")
     Msgbox FolderExists("c:\temp")
     Msgbox FileExists("c:\temp\unzip.exe")
End Sub


Function FileExists(sSource As String) As Variant
     
     Dim WFD As WIN32_FIND_DATA
     Dim hFile As Long
     
     hFile = FindFirstFile(sSource, WFD)
     FileExists = hFile <> INVALID_HANDLE_VALUE
     
     Call FindClose(hFile)
     
End Function

Function DriveExists(drvName As String) As Variant
     
     Dim allDrives As String
     allDrives = Space$(64)
     
     Call GetLogicalDriveStrings(Len(allDrives), allDrives)
     
     DriveExists = Instr(1, allDrives, drvName, 1) > 0
     
End Function

Function FolderExists(sFolder As String) As Variant
     
     Dim hFile As Long
     Dim WFD As WIN32_FIND_DATA
       sFolder = UnQualifyPath(sFolder)
     hFile = FindFirstFile(sFolder, WFD)
     FolderExists = (hFile <> INVALID_HANDLE_VALUE) And  (WFD.dwFileAttributes And FILE_ATTRIBUTE_DIRECTORY)
     If FolderExists = 16 Then
           FolderExists = True
     Else
           FolderExists = False
     End If
     Call FindClose(hFile)
     
End Function

Function UnQualifyPath(Byval sFolder As String) As String
     sFolder = Trim$(sFolder)
     
     If Right$(sFolder, 1) = "\" Then
           UnQualifyPath = Left$(sFolder, Len(sFolder) - 1)
     Else
           UnQualifyPath = sFolder
     End If
     
End Function

[outerspace]

Super,
hast Du auch eine Funktion im Ärmel, die überprüft,
ob eine Datei gerade geöffnet ist ?