CODEWITHSUNDEEP
excelvb.netmime-types
ITM
ITM

Reputation: 1

Writing .xlsx file to disk and reading into a byte array results in error when attempting to open the file

Using VB.NET, we write a .xlsx (Excel Workbook) file to disk and then read into a byte array. Opening the Excel Workbook using File Explorer works correctly, but writing the byte array to the Response output stream and opening the downloaded file in any browser gives an error message (see below).

This error does not occur on regular Excel (.xls) files.

Microsoft Excel: We found a problem with some content in 'xxx.xlsx'. Do you want us to recover as much as we can?

Dim tB As Byte() = File.ReadAllBytes(diskOpts.DiskFileName) 
Response.Clear() 
Response.Buffer = True 
Response.ContentType = sUtilities.Instance.GetMimeType(tExtens) 
Response.AddHeader("Content-Disposition", "filename=" & fRep.Name & "." & tExtens)
Response.OutputStream.Write(tB, 0, tB.Length) `

Upvotes: 0

Views: 222

Answers (1)

dbasnett
dbasnett

Reputation: 11773

Have you tried it like this?

    Response.AddHeader("Content-Disposition", String.Format("attachment; filename={0}", fileName))
    Response.ContentType = "application/vnd.ms-excel"
    Response.WriteFile(fileName)

EDIT

I looked at our website that allows users to download a variety of files. This code works for .xslx files.

                Dim fi As New IO.FileInfo(docPath)
                Response.Clear()
                Response.ClearHeaders()
                Response.ClearContent()
                Dim ext As String = IO.Path.GetExtension(docPath).ToLower
                If ext = ".pdf" Then
                    Response.ContentType = "application/pdf"
                Else
                    Response.ContentType = "application/octet-stream"
                End If
                Response.AppendHeader("Content-Disposition", "attachment; filename=" & IO.Path.GetFileName(docPath))
                Response.AppendHeader("Content-Length", fi.Length.ToString())
                Response.BufferOutput = True
                Response.TransmitFile(docPath)
                Response.End()

Upvotes: 1

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