Hello Everyone

I am developing a project in VB.NET in which I need to use Win32 API
function FindFirstFile()/FindNextFile()/FindClose()
The same code is wroking fine in VB 6.0 , but when I used the code in VB.NET
its giving an error saying that "Object reference is not set to an instance"
at the line where the FindFirstFIle() API is used. Can Anybody tell me why
its happing like this.

Thanks in Advance .

Here I am posting the code I wrote along with the error I got.

Module ProgramShortcuts

     Public Structure mctFileSearchResults

         Dim FileCount As Long

         Dim FileSize As Decimal

         Dim Files() As String

     End Structure

     Private Const MAX_PATH = 260

     Private Const MAXDWORD = &HFFFF

     Private Const INVALID_HANDLE_VALUE = -1

     Private Const FILE_ATTRIBUTE_ARCHIVE = &H20

     Private Const FILE_ATTRIBUTE_DIRECTORY = &H10

     Private Const FILE_ATTRIBUTE_HIDDEN = &H2

     Private Const FILE_ATTRIBUTE_NORMAL = &H80

     Private Const FILE_ATTRIBUTE_READONLY = &H1

     Private Const FILE_ATTRIBUTE_SYSTEM = &H4

     Private Const FILE_ATTRIBUTE_TEMPORARY = &H100

     Private Structure FILETIME

          Dim dwLowDateTime As Long

          Dim dwHighDateTime As Long

     End Structure

     Private Structure WIN32_FIND_DATA

          Dim dwFileAttributes As Long

          Dim ftCreationTime As FILETIME

          Dim ftLastAccessTime As FILETIME

          Dim ftLastWriteTime As FILETIME

          Dim nFileSizeHigh As Long

          Dim nFileSizeLow As Long

          Dim dwReserved0 As Long

          Dim dwReserved1 As Long

          Dim cFileName As String 'line added by Vighneswar

         '''Dim cFileName As String 'line commented by Vighneswar

         '''dim cAlternate As String * 14 'line commented by Vighneswar

          Dim cAlternate As String

     End Structure

     Private Declare Function FindFirstFile Lib "kernel32" Alias
"FindFirstFileA" (ByVal lpFileName As String, ByVal lpFindFileData As
WIN32_FIND_DATA) As Long

     Private Declare Function FindNextFile Lib "kernel32" Alias
"FindNextFileA" (ByVal hFindFile As Long, ByVal lpFindFileData As
WIN32_FIND_DATA) As Long

     Private Declare Function FindClose Lib "kernel32" (ByVal hFindFile As
Long) As Long

Public Sub FileSearchA(ByVal sPath As String, ByVal sFileMask As String,
ByRef taFiles As mctFileSearchResults, _

Optional ByVal bRecursive As Boolean = False, Optional ByVal iRecursionLevel
As Long = -1)

'''On Error GoTo Hell

     Dim sFilename As String

     Dim sFolder As String

     Dim iFolderCount As Long

     Dim aFolders() As String

     Dim aFileMask() As String

     Dim iSearchHandle As Long

     Dim WFD As WIN32_FIND_DATA

     Dim bContinue As Long : bContinue = True

     Dim Ret As Long, X As Long

     WFD.cFileName = Space(MAX_PATH) 'Lines added by Vighneswar

     WFD.cAlternate = Space(14)

  Try

     If Right(sPath, 1) <> "\" Then sPath = sPath & "\"

' Search for subdirectories first and save'em for later

' --------------------------

    If bRecursive Then

         iSearchHandle = FindFirstFile(sPath & "*.*", WFD)                '
Here I got the Error "Object Reference Not Set to an Instacnce of Object"

    If iSearchHandle <> INVALID_HANDLE_VALUE Then

    Do While bContinue

           If (InStr(WFD.cFileName, Chr(0)) > 0) Then WFD.cFileName =
Left(WFD.cFileName, InStr(WFD.cFileName, Chr(0)) - 1)

           sFolder = Trim(WFD.cFileName)

           If (sFolder <> ".") And (sFolder <> "..") Then ' Ignore the
current and encompassing directories

           If WFD.dwFileAttributes And vbDirectory Then

                iFolderCount = iFolderCount + 1

                ReDim Preserve aFolders(iFolderCount)

                aFolders(iFolderCount) = sFolder

            End If

         End If

         bContinue = FindNextFile(iSearchHandle, WFD) 'Get next
subdirectory.

   Loop

        bContinue = FindClose(iSearchHandle)

  End If

  End If

' --------------------------

bContinue = True

' Walk through this directory and sum file sizes.

' --------------------------

' FindFirstFile takes one type at a time, so we'll loop the search for as
many extensions as specified

aFileMask = Split(sFileMask, ";")

For X = 0 To UBound(aFileMask)

' Make sure it's all formatted

     If Left$(aFileMask(X), 1) = "." Then aFileMask(X) = "*" & aFileMask(X)

        If Left$(aFileMask(X), 2) <> "*." Then aFileMask(X) = "*." &
aFileMask(X)

                   iSearchHandle = FindFirstFile(sPath & aFileMask(X), WFD)

                 If iSearchHandle <> INVALID_HANDLE_VALUE Then

                Do While bContinue

                If (InStr(WFD.cFileName, Chr(0)) > 0) Then WFD.cFileName =
Left(WFD.cFileName, InStr(WFD.cFileName, Chr(0)) - 1)

                        sFilename = Trim$(WFD.cFileName)

                         ' It's a file, right?

                        If (sFilename <> ".") And (sFilename <> "..") And
(Not (WFD.dwFileAttributes And vbDirectory) = vbDirectory) Then

                        With taFiles

                              .FileSize = .FileSize + (WFD.nFileSizeHigh *
MAXDWORD) + WFD.nFileSizeLow

                                    .FileCount = .FileCount + 1

                               ReDim Preserve .Files(.FileCount)

                                .Files(.FileCount) = sPath & sFilename

                           End With

                      End If

                     bContinue = FindNextFile(iSearchHandle, WFD) ' Get next
file

           Loop

         bContinue = FindClose(iSearchHandle)

End If

Next

' --------------------------

' If there are sub-directories,

If iFolderCount > 0 Then

' And if we care,

If bRecursive Then

  If iRecursionLevel <> 0 Then ' Recursively walk into them...

           iRecursionLevel = iRecursionLevel - 1

             For X = 1 To iFolderCount

                 FileSearchA(sPath & aFolders(X) & "\", sFileMask, taFiles,
bRecursive, iRecursionLevel)

              Next

End If

End If

End If

Catch ex As Exception

          MsgBox(ex.ToString)

End Try

'''Hell:

End Sub

End Module

Regards  ............ Vighneswar

Your declarations are wrong.  'Long' is a 64-bit type in VB.NET, and thus
'Long's from VB6 need to be changed to 'Int32' or 'Integer'.  I am curious
why you are not using 'System.IO.Directory' and its shared methods for this
purpose instead.

Show quote Hide quote I'm not the OP, but I am happy for this answer.  System.IO.Directory is DOG
SLOW.

Thank You Verymuch

Regards
Vighneswar

Show quoteHide quote

How getting eventhandler attached to an event?
Simple word count
single to string problem
Error setting CSV to display text
My app as system process
Simple TCP communications examples
Thread terminating instantly
How to move the mouse around in vb.net
Move emails (.msg files) between an Outlook inbox and a file direc
How to simulate mouse click in vb.net