Assign Attachment Field To Variable in Access 2010 - image

Question

I'm trying to understand how to work with the new Attachment field that is available in Access 2010. I would like to assign the value from the table directly into a variable. I know that I can do this if I use an intermediary form, but this seems like sloppy coding to rely on a form in order to grab a value from a table. Is there some way to grab what is in an attachment field and assign it directly to a variable? I have multiple instances where this would be handy for me. The first instance is I want to grab a photo stored in an attachment field to assign to the ribbon. A second instance is to load a company logo from a table into a variable and keep it in memory to use throughout the program as needed.
The code I have so far is this, but it gives me a type mismatch error:
Dim ParentRS As Recordset, ChildRS As Recordset, Img As Attachment
Set ParentRS = CurrentDb.OpenRecordset("SELECT * FROM LtblImg;", dbOpenSnapshot)
If ParentRS.RecordCount > 0 Then
Set ChildRS = ParentRS("Img").Value
If ChildRS.RecordCount > 0 Then
Set Img = ChildRS("FileData")
End If
ChildRS.Close
End If
ParentRS.Close

Answer 1

Yes, Dim Img As Attachment looks tempting, but Attachment (which is actually Access.Attachment) refers to an Attachment control that could be used on a form (just like Access.TextBox) and does not appear to be suitable for your intended purpose.
The only native VBA type for storing this sort of binary data is an array of Byte values, but often when dealing with byte arrays we wind up looping through and processing them byte-by-byte, which is tedious and inefficient.
You might consider using a binary ADODB.Stream object as your "variable". You could create a function to retrieve the attachment bytes and return them in a Stream like so
Option Compare Database
Option Explicit
Public Function GetLogoAsStream() As ADODB.Stream
Dim cdb As DAO.Database, rstMain As DAO.Recordset, rstAttach As DAO.Recordset2, fldAttach As DAO.Field2
' Project references required for early binding:
' Windows Script Host Object Model
' Microsoft ActiveX Data Objects 2.8 Library
Dim fso As FileSystemObject, tempFileSpec As String
Static strm As ADODB.Stream
If strm Is Nothing Then
Set fso = New FileSystemObject
tempFileSpec = fso.GetSpecialFolder(TemporaryFolder) & "\" & fso.GetTempName
Set fso = Nothing
Set cdb = CurrentDb
Set rstMain = cdb.OpenRecordset( _
"SELECT [AttachmentFiles] " & _
"FROM [AttachmentsTable] " & _
"WHERE [Description]='SO logo'", _
dbOpenSnapshot)
Set rstAttach = rstMain("AttachmentFiles").Value
' make sure we use the correct file extension
tempFileSpec = tempFileSpec & "." & rstAttach.Fields("FileType").Value
Set fldAttach = rstAttach.Fields("FileData")
fldAttach.SaveToFile tempFileSpec
Set fldAttach = Nothing
rstAttach.Close
Set rstAttach = Nothing
rstMain.Close
Set rstMain = Nothing
Set cdb = Nothing
Set strm = New ADODB.Stream
strm.Type = adTypeBinary
strm.Open
strm.LoadFromFile tempFileSpec
Kill tempFileSpec
End If
strm.Position = 0
Set GetLogoAsStream = strm
End Function
and then if you had, say, a Report like this with an empty Image control
and an On Load event procedure like this to load the Image control's .PictureData from your "variable" (actually a Function returning an ADODB.Stream)
Private Sub Report_Load()
Me.LogoImage.PictureData = GetLogoAsStream.Read
End Sub
it could produce something like this