Uploading '.xlsx' or '.docx' to SharePoint 2007 from ASP.NET app causing file 'corruption'

Question

I have an ASP.NET application wrapped in SharePoint 2007 website. Within this application I allow users to create requests and they can also upload supporting files for the request. When a user uploads supporting docs of type .docx or .xlsx (the only two that I have found to become corrupt so far) they are becoming 'corrupted' in a sense that when I attempt to open them, I'm prompted with a message saying:

"Excel found unreadable content in 'Book1.xlsx'. Do you want to recover the contents of this workbook? If you trust the source of this workbook, click Yes"

When I click yes, it does repair the file and display the contents correctly, but this is unacceptable to the users. I don't even want them to have the problem.

Here is the code (VB.NET) for my upload click event:

Private Sub Upload_Click(ByVal sender As Object, ByVal e As System.EventArgs) Handles btnUpload.Click
    Try
        Dim currentUser As SPUser = SPContext.Current.Web.AllUsers("SHAREPOINT\SYSTEM")
        Dim currentUserToken As SPUserToken = currentUser.UserToken
        Using currentSite As SPSite = New SPSite(SPContext.Current.Web.Url, currentUserToken)

            Using CurrentWeb As SPWeb = currentSite.OpenWeb
                CurrentWeb.AllowUnsafeUpdates = True

                Dim attachmentList As SPList = CurrentWeb.Lists("Requests")

                Dim item As SPListItem = attachmentList.GetItemById(CurrentRequestId)

                If FileUpload.PostedFile.ContentLength > Nothing And FileUpload.HasFile Then
                    Dim fStream As Stream = FileUpload.PostedFile.InputStream
                    Dim contents() As Byte = New Byte(fStream.Length) {}

                    fStream.Read(contents, 0, CType(fStream.Length, Integer))
                    fStream.Close()
                    fStream.Dispose()

                    Dim attachments As SPAttachmentCollection = item.Attachments
                    Dim fileName As String = Path.GetFileName(FileUpload.PostedFile.FileName)
                    attachments.Add(fileName, contents)
                    item.Update()
                Else
                    Page.ClientScript.RegisterStartupScript(Page.GetType(), "disp_msg", "<script type='text/javascript'>alert('The file contains 0 Bytes of data and will be deleted.'); </script>")
                End If
            End Using
        End Using
        DisplayAttachment(CurrentRequestId)
        btnSave.Focus()
    Catch ex As Exception
        Page.ClientScript.RegisterStartupScript(Page.GetType(), "disp_msg", "<script type='text/javascript'>alert('Error Uploading File: " & ex.Message & "'); </script>")
    End Try
End Sub

Any help would be appreciated. Thanks in advance.

Answer 1

It will be the mode you are doing the upload.

Convert the byte array into a stream and you won't get any corruptions. You need to do this by saving the byte array you are creating into a file or something, then open it into a stream. The bug is in .Add() not your code.

Not to hot on my VB.Net at the moment so I can't tell you exactly what to write, but I hope that the fix is straight forward enough.

Summary:

If you use Files.Add corrupts files uploaded as a byte array, so save your byte array as a file and load as a file stream and then use that to add to the Attachment collection.