I want to decode a string (which I got via readAsDataUrl()) to bytes.
At first, I remove the data:*/*;base64, then I call the following:
Option Explicit
Private Const CRYPT_STRING_BASE64 As Long = &H1&
Private Declare Function CryptStringToBinaryW Lib "Crypt32.dll" ( _
ByVal pszString As Long, _
ByVal cchString As Long, _
ByVal dwFlags As Long, _
ByVal pbBinary As Long, _
ByRef pcbBinary As Long, _
ByVal pdwSkip As Long, _
ByVal pdwFlags As Long) As Long
Public Function DecodeBase64(ByVal strData As String) As Byte()
Dim Buffer() As Byte
Dim dwBinaryBytes As Long
dwBinaryBytes = LenB(strData)
ReDim Buffer(dwBinaryBytes - 1) As Byte
'within the following call, VB6 crashes:
If CryptStringToBinaryW(StrPtr(strData), LenB(strData), CRYPT_STRING_BASE64, _
VarPtr(Buffer(0)), dwBinaryBytes, 0, 0) Then
ReDim Preserve Buffer(dwBinaryBytes - 1) As Byte
DecodeBase64 = Buffer
End If
Erase Buffer
End Function
Now I call this:
Dim s$
'code to get base64 string
'code to strip for example "data:image/jpeg;base64,"
Dim nBytes() As Byte
nBytes = DecodeBase64(s) 'Here VB6 crashes
Edit:
I am using the following alternative version now, and it works, but I wonder what the error is:
Public Function DecodeBase64(ByVal sBase64Buf As String) As Byte()
Const CRYPT_STRING_BASE64 As Long = 1
Const CRYPT_STRING_NOCRLF As Long = &H40000000
Dim bTmp() As Byte
Dim lLen As Long
Dim dwActualUsed As Long
'Get output buffer length
If CryptStringToBinary(StrPtr(sBase64Buf), Len(sBase64Buf), CRYPT_STRING_BASE64, StrPtr(vbNullString), lLen, 0&, dwActualUsed) = 0 Then
'RaiseEvent Error(Err.LastDllError, CSB, Routine)
GoTo ReleaseHandles
End If
'Convert Base64 to binary.
ReDim bTmp(lLen - 1)
If CryptStringToBinary(StrPtr(sBase64Buf), Len(sBase64Buf), CRYPT_STRING_BASE64, VarPtr(bTmp(0)), lLen, 0&, dwActualUsed) = 0 Then
'RaiseEvent Error(Err.LastDllError, CSB, Routine)
GoTo ReleaseHandles
Else
'm_bData = bTmp
End If
ReleaseHandles:
DecodeBase64 = bTmp
End Function
Edit:
In version 1, dwBinaryBytes is 156080 in this line:
dwBinaryBytes = LenB(strData)
and in version 2, lLen is 58528 in this line:
ReDim bTmp(lLen - 1)
Why the discrepancy, and why didn't the author notice that?
The "CryptStringToBinaryW" requires the number of characters in the string as a parameter. That is returned by the "Len" function. You used the "LenB" function which returns the number of bytes in the string which is larger than the number of characters in the string so the function attempted to access memory past the end of the string which caused the crash.
Related
I have a base64 string which was generated from an image using another application. Now on my application I want to convert the base64 string to byte and display it on a PictureBox.
I already found a sample application which takes a byte input and sets a PictureBox image. Unfortunately the sample application gets the byte array from an image and just translates it back. Here's the function it uses.
Public Function PictureFromByteStream(b() As Byte) As IPicture
Dim LowerBound As Long
Dim ByteCount As Long
Dim hMem As Long
Dim lpMem As Long
Dim IID_IPicture(15)
Dim istm As stdole.IUnknown
On Error GoTo Err_Init
If UBound(b, 1) < 0 Then
Exit Function
End If
LowerBound = LBound(b)
ByteCount = (UBound(b) - LowerBound) + 1
hMem = GlobalAlloc(&H2, ByteCount)
If hMem <> 0 Then
lpMem = GlobalLock(hMem)
If lpMem <> 0 Then
MoveMemory ByVal lpMem, b(LowerBound), ByteCount
Call GlobalUnlock(hMem)
If CreateStreamOnHGlobal(hMem, 1, istm) = 0 Then
If CLSIDFromString(StrPtr("{7BF80980-BF32-101A-8BBB-00AA00300CAB}"), IID_IPicture(0)) = 0 Then
Call OleLoadPicture(ByVal ObjPtr(istm), ByteCount, 0, IID_IPicture(0), PictureFromByteStream)
End If
End If
End If
End If
Exit Function
Err_Init:
If Err.Number = 9 Then
'Uninitialized array
MsgBox "You must pass a non-empty byte array to this function!"
Else
MsgBox Err.Number & " - " & Err.Description
End If
End Function
Here's the function I found to convert a base64 string to a byte, it seems to be converting it but when I pass the byte data to the above function, no image appears.
Private Function DecodeBase64(ByVal strData As String) As Byte()
Dim objXML As MSXML2.DOMDocument
Dim objNode As MSXML2.IXMLDOMElement
' help from MSXML
Set objXML = New MSXML2.DOMDocument
Set objNode = objXML.createElement("b64")
objNode.dataType = "bin.base64"
objNode.Text = strData
DecodeBase64 = objNode.nodeTypedValue
' thanks, bye
Set objNode = Nothing
Set objXML = Nothing
End Function
And here's my code calling the functions.
Dim b() As Byte
b = DecodeBase64(Text1.Text)
Dim pic As StdPicture
Set pic = PictureFromByteStream(b)
Set Picture1.Picture = pic
Try this:
Option Explicit
Private Const CRYPT_STRING_BASE64 As Long = &H1&
Private Const STRING_IPICTURE_GUID As String = "{7BF80980-BF32-101A-8BBB-00AA00300CAB}"
Private Declare Function CryptStringToBinaryW Lib "Crypt32.dll" ( _
ByVal pszString As Long, _
ByVal cchString As Long, _
ByVal dwFlags As Long, _
ByVal pbBinary As Long, _
ByRef pcbBinary As Long, _
ByVal pdwSkip As Long, _
ByVal pdwFlags As Long) As Long
Private Declare Function CreateStreamOnHGlobal Lib "ole32.dll" ( _
ByRef hGlobal As Any, _
ByVal fDeleteOnResume As Long, _
ByRef ppstr As Any) As Long
Private Declare Function OleLoadPicture Lib "olepro32.dll" ( _
ByVal lpStream As IUnknown, _
ByVal lSize As Long, _
ByVal fRunMode As Long, _
ByRef riid As GUID, _
ByRef lplpObj As Any) As Long
Private Declare Function CLSIDFromString Lib "ole32.dll" ( _
ByVal lpsz As Long, _
ByRef pclsid As GUID) As Long
Type GUID
Data1 As Long
Data2 As Integer
Data3 As Integer
Data4(7) As Byte
End Type
Public Function DecodeBase64(ByVal strData As String) As Byte()
Dim Buffer() As Byte
Dim dwBinaryBytes As Long
dwBinaryBytes = LenB(strData)
ReDim Buffer(dwBinaryBytes - 1) As Byte
If CryptStringToBinaryW(StrPtr(strData), LenB(strData), CRYPT_STRING_BASE64, _
VarPtr(Buffer(0)), dwBinaryBytes, 0, 0) Then
ReDim Preserve Buffer(dwBinaryBytes - 1) As Byte
DecodeBase64 = Buffer
End If
Erase Buffer
End Function
Public Function PictureFromByteStream(ByRef b() As Byte) As IPicture
On Error GoTo errorHandler
Dim istrm As IUnknown
Dim tGuid As GUID
If Not CreateStreamOnHGlobal(b(LBound(b)), False, istrm) Then
CLSIDFromString StrPtr(STRING_IPICTURE_GUID), tGuid
OleLoadPicture istrm, UBound(b) - LBound(b) + 1, False, tGuid, PictureFromByteStream
End If
Set istrm = Nothing
Exit Function
errorHandler:
Debug.Print "Error in converting to IPicture."
End Function
How to Convert string in to Byte array that contain &H81 in first index if the byte array mybyte(0) with
i need to check in my byte array
Private Declare Sub CopyMemory _
Lib "kernel32" _
Alias "RtlMoveMemory" (Destination As Any, _
Source As Any, _
ByVal Length As Long)
Private Sub cmdCommand1_Click()
Dim str As String
Dim BT() As Byte
BT() = StrToByte(tbMsg.Text)
If BT(0) = &H81 Then
'MyCode
End If
End Sub
the If mybyte(0) = &H81 Then condition is allays getting false
and currently i'm using this string to byte converting method
Public Function StrToByte(strInput As String) As Byte()
Dim lPntr As Long
Dim bTmp() As Byte
Dim bArray() As Byte
If Len(strInput) = 0 Then Exit Function
ReDim bTmp(LenB(strInput) - 1) 'Memory length
ReDim bArray(Len(strInput) - 1) 'String length
CopyMemory bTmp(0), ByVal StrPtr(strInput), LenB(strInput)
For lPntr = 0 To UBound(bArray)
If bTmp(lPntr * 2 + 1) > 0 Then
bArray(lPntr) = Asc(Mid$(strInput, lPntr + 1, 1))
Else
bArray(lPntr) = bTmp(lPntr * 2)
End If
Next lPntr
StrToByte = bArray
End Function
A typo I think, it should be:
If BT(0) = &H81 Then
Not
If mybyte(0) = &H81 Then
Your code seems to be converting the double byte unicode string into a single byte representation of the string, this will result in garbage for any character with a codepoint > 255.
If thats ok your code is equivalent to the built in:
BT() = StrConv(strInput, vbFromUnicode)
I'm currently working on a program that takes a list of computernames, runs a series of command prompt queries on the computer in question, and then exports the information out to an excel file. So, for example, my program runs this command through CMD:
wmic /node:COMPUTERNAME /user:USER /password:PASSWORD cpu get name
and this returns the given computers cpu name/speed, etc. The issue that I'm running into is that I can export it to a new text file, which then pulls in the headings, so instead of just returning "Intel Core 2 Duo 2.66GHz", it returns this.
Name
Intel Core 2 Duo 2.66 GHz
However, I would RATHER export this out to excel, not a text file. But when I do it for more than one computer, it exports in everything as one cell, instead of parsing the data out.
So my question is: using command prompt, is there anyway to send out or parse out data into an excel file, and is there a way to do so that pulls JUST certain information that you specify?
youc can use this VBA code to run in excel cells your CLI command and return the result as value of each cells.
Function CMD(commande As String)
CMD = GetCommandOutput(commande)
End Function
in other module add this
'Attribute VB_Name = "CmdOutput"
Option Explicit
''''''''''''''''''''''''''''''''''''''''
' Joacim Andersson, Brixoft Software
' http://www.brixoft.net
''''''''''''''''''''''''''''''''''''''''
' STARTUPINFO flags
Private Const STARTF_USESHOWWINDOW = &H1
Private Const STARTF_USESTDHANDLES = &H100
' ShowWindow flags
Private Const SW_HIDE = 0
' DuplicateHandle flags
Private Const DUPLICATE_CLOSE_SOURCE = &H1
Private Const DUPLICATE_SAME_ACCESS = &H2
' Error codes
Private Const ERROR_BROKEN_PIPE = 109
Private Type SECURITY_ATTRIBUTES
nLength As Long
lpSecurityDescriptor As Long
bInheritHandle As Long
End Type
Private Type STARTUPINFO
cb As Long
lpReserved As String
lpDesktop As String
lpTitle As String
dwX As Long
dwY As Long
dwXSize As Long
dwYSize As Long
dwXCountChars As Long
dwYCountChars As Long
dwFillAttribute As Long
dwFlags As Long
wShowWindow As Integer
cbReserved2 As Integer
lpReserved2 As Long
hStdInput As Long
hStdOutput As Long
hStdError As Long
End Type
Private Type PROCESS_INFORMATION
hProcess As Long
hThread As Long
dwProcessId As Long
dwThreadId As Long
End Type
Private Declare Function CreatePipe _
Lib "kernel32" ( _
phReadPipe As Long, _
phWritePipe As Long, _
lpPipeAttributes As Any, _
ByVal nSize As Long) As Long
Private Declare Function ReadFile _
Lib "kernel32" ( _
ByVal hFile As Long, _
lpBuffer As Any, _
ByVal nNumberOfBytesToRead As Long, _
lpNumberOfBytesRead As Long, _
lpOverlapped As Any) As Long
Private Declare Function CreateProcess _
Lib "kernel32" Alias "CreateProcessA" ( _
ByVal lpApplicationName As String, _
ByVal lpCommandLine As String, _
lpProcessAttributes As Any, _
lpThreadAttributes As Any, _
ByVal bInheritHandles As Long, _
ByVal dwCreationFlags As Long, _
lpEnvironment As Any, _
ByVal lpCurrentDriectory As String, _
lpStartupInfo As STARTUPINFO, _
lpProcessInformation As PROCESS_INFORMATION) As Long
Private Declare Function GetCurrentProcess _
Lib "kernel32" () As Long
Private Declare Function DuplicateHandle _
Lib "kernel32" ( _
ByVal hSourceProcessHandle As Long, _
ByVal hSourceHandle As Long, _
ByVal hTargetProcessHandle As Long, _
lpTargetHandle As Long, _
ByVal dwDesiredAccess As Long, _
ByVal bInheritHandle As Long, _
ByVal dwOptions As Long) As Long
Private Declare Function CloseHandle _
Lib "kernel32" ( _
ByVal hObject As Long) As Long
Private Declare Function OemToCharBuff _
Lib "user32" Alias "OemToCharBuffA" ( _
lpszSrc As Any, _
ByVal lpszDst As String, _
ByVal cchDstLength As Long) As Long
' Function GetCommandOutput
'
' sCommandLine: [in] Command line to launch
' blnStdOut [in,opt] True (defualt) to capture output to STDOUT
' blnStdErr [in,opt] True to capture output to STDERR. False is default.
' blnOEMConvert: [in,opt] True (default) to convert DOS characters to Windows, False to skip conversion
'
' Returns: String with STDOUT and/or STDERR output
'
Public Function GetCommandOutput(sCommandLine As String, _
Optional blnStdOut As Boolean = True, _
Optional blnStdErr As Boolean = False, _
Optional blnOEMConvert As Boolean = True _
) As String
Dim hPipeRead As Long, hPipeWrite1 As Long, hPipeWrite2 As Long
Dim hCurProcess As Long
Dim sa As SECURITY_ATTRIBUTES
Dim si As STARTUPINFO
Dim pi As PROCESS_INFORMATION
Dim baOutput() As Byte
Dim sNewOutput As String
Dim lBytesRead As Long
Dim fTwoHandles As Boolean
Dim lRet As Long
Dim endTime As Date
Const BUFSIZE = 1024 ' pipe buffer size
endTime = Now + TimeValue("00:00:05")
' At least one of them should be True, otherwise there's no point in calling the function
If (Not blnStdOut) And (Not blnStdErr) Then
Err.Raise 5 ' Invalid Procedure call or Argument
End If
' If both are true, we need two write handles. If not, one is enough.
fTwoHandles = blnStdOut And blnStdErr
ReDim baOutput(BUFSIZE - 1) As Byte
With sa
.nLength = Len(sa)
.bInheritHandle = 1 ' get inheritable pipe handles
End With
If CreatePipe(hPipeRead, hPipeWrite1, sa, BUFSIZE) = 0 Then
Exit Function
End If
hCurProcess = GetCurrentProcess()
' Replace our inheritable read handle with an non-inheritable. Not that it
' seems to be necessary in this case, but the docs say we should.
Call DuplicateHandle(hCurProcess, hPipeRead, hCurProcess, hPipeRead, 0&, _
0&, DUPLICATE_SAME_ACCESS Or DUPLICATE_CLOSE_SOURCE)
' If both STDOUT and STDERR should be redirected, get an extra handle.
If fTwoHandles Then
Call DuplicateHandle(hCurProcess, hPipeWrite1, hCurProcess, hPipeWrite2, 0&, _
1&, DUPLICATE_SAME_ACCESS)
End If
With si
.cb = Len(si)
.dwFlags = STARTF_USESHOWWINDOW Or STARTF_USESTDHANDLES
.wShowWindow = SW_HIDE ' hide the window
If fTwoHandles Then
.hStdOutput = hPipeWrite1
.hStdError = hPipeWrite2
ElseIf blnStdOut Then
.hStdOutput = hPipeWrite1
Else
.hStdError = hPipeWrite1
End If
End With
If CreateProcess(vbNullString, sCommandLine, ByVal 0&, ByVal 0&, 1, 0&, _
ByVal 0&, vbNullString, si, pi) Then
' Close thread handle - we don't need it
Call CloseHandle(pi.hThread)
' Also close our handle(s) to the write end of the pipe. This is important, since
' ReadFile will *not* return until all write handles are closed or the buffer is full.
Call CloseHandle(hPipeWrite1)
hPipeWrite1 = 0
If hPipeWrite2 Then
Call CloseHandle(hPipeWrite2)
hPipeWrite2 = 0
End If
Do
' Add a DoEvents to allow more data to be written to the buffer for each call.
' This results in fewer, larger chunks to be read.
'DoEvents
If ReadFile(hPipeRead, baOutput(0), BUFSIZE, lBytesRead, ByVal 0&) = 0 Then
Exit Do
End If
If Now > endTime Then
GetCommandOutput = GetCommandOutput & "CMD(""TimeOut"")"
Exit Do
End If
If blnOEMConvert Then
' convert from "DOS" to "Windows" characters
sNewOutput = String$(lBytesRead, 0)
Call OemToCharBuff(baOutput(0), sNewOutput, lBytesRead)
Else
' perform no conversion (except to Unicode)
sNewOutput = Left$(StrConv(baOutput(), vbUnicode), lBytesRead)
End If
GetCommandOutput = GetCommandOutput & sNewOutput
' If you are executing an application that outputs data during a long time,
' and don't want to lock up your application, it might be a better idea to
' wrap this code in a class module in an ActiveX EXE and execute it asynchronously.
' Then you can raise an event here each time more data is available.
'RaiseEvent OutputAvailabele(sNewOutput)
Loop
' When the process terminates successfully, Err.LastDllError will be
' ERROR_BROKEN_PIPE (109). Other values indicates an error.
Call CloseHandle(pi.hProcess)
Else
GetCommandOutput = "Failed to create process, check the path of the command line."
End If
' clean up
Call CloseHandle(hPipeRead)
If hPipeWrite1 Then
Call CloseHandle(hPipeWrite1)
End If
If hPipeWrite2 Then
Call CloseHandle(hPipeWrite2)
End If
End Function
wmic can create CSV output, which is a text format that Excel recognizes:
wmic /node:HOST /user:USER /password:PASS /output:C:\path\to\output.csv cpu get name /format:CSV
You need administrative privileges for this, though, otherwise you'll get an error like this:
Invalid XSL format (or) file name.
Public Declare Function FindMimeFromData Lib "urlmon.dll" ( _
ByVal pbc As Long, _
ByVal pwzUrl As String, _
pBuffer As Any, _
cbSize As Long, _
ByVal pwzMimeProposed As String, _
dwMimeFlags As Long, _
ppwzMimeOut As Long, _
dwReserved As Long) As Long
In VB6, I can't seem to figure out how to pass the pBuffer parameter of the first 256 characters of a file. When I try to use a Dim buffer() As Byte and populate that, and pass it as the parameter, it throws the error of wrong param even those of the definition is Any.
I've tried to use this example, but passing the entire file name from a file system doesn't seem to work. so I have to try sending it like the C# example with the first 256 bytes of the file.
Can anyone help?
I played around with the following Declare, and built up some code around it. There are two wrappers, GetMimeTypeFromUrl() and GetMimeTypeFromData(). I found the former only worked when you used simple URLs such as http://host.com/file.xtn. You may have to play around with the other flags.
However, the other wrapper function sounds like what you need.
Note that all the string pointers are declared As Long, and I pass the underlying UTF-16 VB string as a pointer using StrPtr().
Also note that you have to use CoTaskMemFree() to free the output ppwzMimeOut string pointer, otherwise you will leak memory.
Option Explicit
Private Declare Function FindMimeFromData Lib "Urlmon.dll" ( _
ByVal pBC As Long, _
ByVal pwzUrl As Long, _
ByVal pBuffer As Long, _
ByVal cbSize As Long, _
ByVal pwzMimeProposed As Long, _
ByVal dwMimeFlags As Long, _
ByRef ppwzMimeOut As Long, _
ByVal dwReserved As Long _
) As Long
'
' Flags:
'
' Default
Private Const FMFD_DEFAULT As Long = &H0
' Treat the specified pwzUrl as a file name.
Private Const FMFD_URLASFILENAME As Long = &H1
' Internet Explorer 6 for Windows XP SP2 and later. Use MIME-type detection even if FEATURE_MIME_SNIFFING is detected. Usually, this feature control key would disable MIME-type detection.
Private Const FMFD_ENABLEMIMESNIFFING As Long = &H2
' Internet Explorer 6 for Windows XP SP2 and later. Perform MIME-type detection if "text/plain" is proposed, even if data sniffing is otherwise disabled. Plain text may be converted to text/html if HTML tags are detected.
Private Const FMFD_IGNOREMIMETEXTPLAIN As Long = &H4
' Internet Explorer 8. Use the authoritative MIME type specified in pwzMimeProposed. Unless FMFD_IGNOREMIMETEXTPLAIN is specified, no data sniffing is performed.
Private Const FMFD_SERVERMIME As Long = &H8
' Internet Explorer 9. Do not perform detection if "text/plain" is specified in pwzMimeProposed.
Private Const FMFD_RESPECTTEXTPLAIN As Long = &H10
' Internet Explorer 9. Returns image/png and image/jpeg instead of image/x-png and image/pjpeg.
Private Const FMFD_RETURNUPDATEDIMGMIMES As Long = &H20
'
' Return values:
'
' The operation completed successfully.
Private Const S_OK As Long = 0&
' The operation failed.
Private Const E_FAIL As Long = &H80000008
' One or more arguments are invalid.
Private Const E_INVALIDARG As Long = &H80000003
' There is insufficient memory to complete the operation.
Private Const E_OUTOFMEMORY As Long = &H80000002
'
' String routines
'
Private Declare Function lstrlen Lib "Kernel32.dll" Alias "lstrlenW" ( _
ByVal lpString As Long _
) As Long
Private Declare Sub CopyMemory Lib "Kernel32.dll" Alias "RtlMoveMemory" (ByVal pDest As Long, ByVal pSrc As Long, ByVal nCount As Long)
Private Declare Sub CoTaskMemFree Lib "Ole32.dll" ( _
ByVal pv As Long _
)
Private Function CopyPointerToString(ByVal in_pString As Long) As String
Dim nLen As Long
' Need to copy the data at the string pointer to a VB string buffer.
' Get the length of the string, allocate space, and copy to that buffer.
nLen = lstrlen(in_pString)
CopyPointerToString = Space$(nLen)
CopyMemory StrPtr(CopyPointerToString), in_pString, nLen * 2
End Function
Private Function GetMimeTypeFromUrl(ByRef in_sUrl As String, ByRef in_sProposedMimeType As String) As String
Dim pMimeTypeOut As Long
Dim nRet As Long
nRet = FindMimeFromData(0&, StrPtr(in_sUrl), 0&, 0&, StrPtr(in_sProposedMimeType), FMFD_DEFAULT, pMimeTypeOut, 0&)
If nRet = S_OK Then
GetMimeTypeFromUrl = CopyPointerToString(pMimeTypeOut)
CoTaskMemFree pMimeTypeOut
Else
Err.Raise nRet
End If
End Function
Private Function GetMimeTypeFromData(ByRef in_abytData() As Byte, ByRef in_sProposedMimeType As String) As String
Dim nLBound As Long
Dim nUBound As Long
Dim pMimeTypeOut As Long
Dim nRet As Long
nLBound = LBound(in_abytData)
nUBound = UBound(in_abytData)
nRet = FindMimeFromData(0&, 0&, VarPtr(in_abytData(nLBound)), nUBound - nLBound + 1, StrPtr(in_sProposedMimeType), FMFD_DEFAULT, pMimeTypeOut, 0&)
If nRet = S_OK Then
GetMimeTypeFromData = CopyPointerToString(pMimeTypeOut)
CoTaskMemFree pMimeTypeOut
Else
Err.Raise nRet
End If
End Function
Private Sub Command1_Click()
Dim sRet As String
Dim abytData() As Byte
sRet = GetMimeTypeFromUrl("http://msdn.microsoft.com/en-us/library/ms775107%28v=vs.85%29.aspx", vbNullString)
Debug.Print sRet
abytData() = StrConv("<HTML><HEAD><TITLE>Stuff</TITLE></HEAD><BODY>Test me</BODY></HTML>", vbFromUnicode)
sRet = GetMimeTypeFromData(abytData(), vbNullString)
Debug.Print sRet
End Sub
Is there any way to convert from \Device\HarddiskVolume1\programfile\explorer.exe to C:\programfile\explorer.exe in visual basic 6?
thanks
Try this
Option Explicit
Private Declare Function QueryDosDevice Lib "kernel32" Alias "QueryDosDeviceA" (ByVal lpDeviceName As String, ByVal lpTargetPath As String, ByVal ucchMax As Long) As Long
Private Sub Command1_Click()
Debug.Print pvReplaceDevice("\Device\HarddiskVolume1\aaa.txt")
End Sub
Private Function pvReplaceDevice(sPath As String) As String
Dim sDrive As String
Dim sDevice As String
Dim lIdx As Long
For lIdx = 0 To 25
sDrive = Chr$(65 + lIdx) & ":"
sDevice = Space(1000)
If QueryDosDevice(sDrive, sDevice, Len(sDevice)) <> 0 Then
sDevice = Left$(sDevice, InStr(sDevice, Chr$(0)) - 1)
' Debug.Print sDrive; "="; sDevice
If LCase$(Left$(sPath, Len(sDevice))) = LCase$(sDevice) Then
pvReplaceDevice = sDrive & Mid$(sPath, Len(sDevice) + 1)
Exit Function
End If
End If
Next
pvReplaceDevice = sPath
End Function
If you want an efficient use of API functions, create a class - "DiskDevice"
Option Explicit
Private Declare Function GetLogicalDriveStrings Lib "Kernel32" Alias "GetLogicalDriveStringsW" ( _
ByVal nBufferLength As Long, _
ByVal lpBuffer As Long _
) As Long
Private Declare Function QueryDosDevice Lib "Kernel32.dll" Alias "QueryDosDeviceW" ( _
ByVal lpDeviceName As Long, _
ByVal lpTargetPath As Long, _
ByVal ucchMax As Long _
) As Long
Private m_colDrivesKeyedByDevice As VBA.Collection
Private Sub Class_Initialize()
Dim sDriveStrings As String
Dim vasDriveStrings As Variant
Dim nIndex As Long
Dim sDrive As String
' Allocate max size buffer [A-Z]:\\\0 and retrieve all drives on the system.
sDriveStrings = Space$(105)
GetLogicalDriveStrings 1000, StrPtr(sDriveStrings)
' Split over the null chars between each substring.
vasDriveStrings = Split(sDriveStrings, vbNullChar)
Set m_colDrivesKeyedByDevice = New VBA.Collection
' Iterate through each drive string (escaping later if any item is null string).
For nIndex = 0 To UBound(vasDriveStrings)
sDrive = Left$(vasDriveStrings(nIndex), 2) ' Ignore the backslash.
If Len(sDrive) = 0 Then
Exit For
End If
' Create mapping from Drive => Device
m_colDrivesKeyedByDevice.Add sDrive, GetDeviceForDrive(sDrive)
Next nIndex
End Sub
' Retrieve the device string \device\XXXXXX for the drive X:
Private Function GetDeviceForDrive(ByRef the_sDrive As String)
Const knBufferLen As Long = 1000
Dim sBuffer As String
Dim nRet As Long
sBuffer = Space$(knBufferLen)
nRet = QueryDosDevice(StrPtr(the_sDrive), StrPtr(sBuffer), knBufferLen)
GetDeviceForDrive = Left$(sBuffer, nRet - 2) ' Ignore 2 terminating null chars.
End Function
Public Function GetFilePathFromDevicePath(ByRef the_sDevicePath As String) As String
Dim nPosSecondBackslash As Long
Dim nPosThirdBackslash As Long
Dim sDevice As String
Dim sDisk As String
' Path is always \Device\<device>\path1\path2\etc. Just get everything before the third backslash.
nPosSecondBackslash = InStr(2, the_sDevicePath, "\")
nPosThirdBackslash = InStr(nPosSecondBackslash + 1, the_sDevicePath, "\")
sDevice = Left(the_sDevicePath, nPosThirdBackslash - 1)
sDisk = m_colDrivesKeyedByDevice.Item(sDevice) ' Lookup
' Reassemble, this time with disk.
GetFilePathFromDevicePath = sDisk & Mid$(the_sDevicePath, nPosThirdBackslash)
End Function
Now, you use code like:
Set m_oDiskDevice = New DiskDevice
...
sMyPath = m_oDiskDevice.GetFilePathFromDevicePath("\Device\HarddiskVolume1\programfile\explorer.exe")
That way you don't have to call the API functions multiple times - you just do a collection lookup.