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VB Forum / General 2 / September 2003Using blobs in VBA
I do apologize if this isn't the proper newsgroup, but I've found quite a lot of potential news-group. My problem is this: I'm trying to integrate our Oracle database with word. The database contains amongst other type word documents, I want to provide the end user a way to retrieve a document from the database edit it in word and write it back to the database afterwards. I've used oo4o for the job, but after retrieving the document in a variant variable I'm stuck, I've tried to write the variant to disk in order to read it later on, but the FileSystemObject and the WriteLine/Write methods doesn't accept variant variables, and the Put statement writes record information at the beginning of the file, causing the file to become unreadable. Does anyone know of a way to convert a variant variable to a word document? Kind regards, Kim Brandt Jensen ... > Does anyone know of a way to convert a variant variable to a word document? ... It would help to know the Variant subtype -- it's probably a byte array (good) or a string (bad). "Debug.Print VarType(<Variable>)" should tell. Murphy www.ConstantThought.com Hi Murphy, it returns an integer 8209, in my documentation that number is not listed. Do you know of a complete list of datatypes and their correlating vartype values? > ... > > Does anyone know of a way to convert a variant variable to a word [quoted text clipped - 6 lines] > Murphy > www.ConstantThought.com (Reply inline) ... > it returns an integer 8209, in my documentation that number is not listed. > Do you know of a complete list of datatypes and their correlating vartype > values? 8209 is vbArray logically ORed against vbByte -- a byte array. ... > > > Does anyone know of a way to convert a variant variable to a word > > document? ... Using my libraries (available on my site), you can do this in four lines of code... Require VarType(V) = (vbArray Or vbByte), "Operation only valid on Byte Array Variants", vbeTypeMismatch Dim F As New CFile F.OpenFile "out.doc", fatGenericWrite, fcdCreateAlways F.WriteData PeekLong(PeekLong(VarPtr(V) + 8) + 12), UBound(V) - LBound(V) + 1 (Where V is the Variant holding the blob) Otherwise, you can use the following: Private Const GENERIC_WRITE = &H40000000 Private Const CREATE_ALWAYS = 2 Private Declare Function CreateFile Lib "kernel32" Alias "CreateFileA" (ByVal lpFileName As String, ByVal dwDesiredAccess As Long, ByVal dwShareMode As Long, lpSecurityAttributes As Any, ByVal dwCreationDisposition As Long, ByVal dwFlagsAndAttributes As Long, ByVal hTemplateFile As Long) As Long Private Declare Function CloseHandle Lib "kernel32" (ByVal hObject As Long) As Long Private Declare Function WriteFile Lib "kernel32" (ByVal hFile As Long, lpBuffer As Any, ByVal nNumberOfBytesToWrite As Long, lpNumberOfBytesWritten As Long, lpOverlapped As Any) As Long Private Declare Sub MoveMemory Lib "kernel32" Alias "RtlMoveMemory" (Destination As Any, Source As Any, ByVal Length As Long) Sub SaveVariantByteArray(FileName As String, Data As Variant) If VarType(Data) <> (vbArray Or vbByte) Then Err.Raise 5 End If Dim hFile As Long hFile = CreateFile(FileName, GENERIC_WRITE, 0, ByVal 0&, CREATE_ALWAYS, 0, 0) If hFile = 0 Then Err.Raise 10101 End If Dim TempL As Long MoveMemory TempL, ByVal VarPtr(Data) + 8, 4 MoveMemory TempL, ByVal TempL + 12, 4 WriteFile hFile, ByVal TempL, UBound(Data) - LBound(Data) + 1, 0, ByVal 0& CloseHandle hFile End Sub This should all be fairly clear, except the two MoveMemory() lines. A quick explaination of them: A Variant is a VARIANT structure (see MSDN). Offset 8 bytes into the structure is the real data that the Variant is holding. In the case of a byte array, it's the address of a SAFEARRAY structure (see MSDN). Offset 12 bytes into the SAFEARRAY structure is the address of the array's data, which is what you want to write to disk. Murphy www.ConstantThought.com Oh. I forgot to mention the simple, terrible, slow, but nonetheless working method of simply iterating through the array writing each element individually using the Put statement. You could probably do similar with the FSO using Chr$(), but at the risk of Byte->UnicodeChar->ASCIIChar conversion problems (not to mention that it'd be even slower). This is certainly a much simpler solution than the one I gave in the previous post, but I would never use it. Murphy www.ConstantThought.com |
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