Problems reading an Excel file in VB.net - vb.net

Question

I have been trying to upload and read an Excel file (.xls, or .xlsx)
I am upploading sucessfully using this code:
Protected Sub btnUpload_Click(ByVal sender As Object, ByVal e As System.EventArgs) Handles btnUpload.Click
Dim filepath As String = ""
If FileUpload1.HasFile Then
Try
Dim filename As String = FileUpload1.PostedFile.FileName
Dim extension = (filename.Substring(filename.LastIndexOf("."), (filename.Length() - filename.LastIndexOf("."))))
If extension = ".xlsx" Or extension = ".xls" Then
filepath = "\" & Common.toUnix(Now) & "_" & filename
FileUpload1.SaveAs(Server.MapPath("~/") & filepath)
' ==== NOW READ THE FILE
Else
StatusLabel.InnerText = "Only Excel file types are accepted (.xls/.xlsx)<br> File Uploaded had extension: " & extension
End If
Catch ex As Exception
StatusLabel.InnerText = "Upload status: The file could not be uploaded. The following error occured: " + ex.ToString()
End Try
End If
End Sub
It uploads OK, but when trying to read the file I get this error:
System.Data.OleDb.OleDbException (0x80004005): The Microsoft Jet database engine cannot open the file ''. It is already opened exclusively by another user, or you need permission to view its data.
I am using code to read similar to this:
vb.net traversing an xls / xlsx file?
Therefore the connection is as follows:
Dim connString As String = "Provider=Microsoft.Jet.OLEDB.4.0" & _
";Data Source=" & ExcelFile & _
";Extended Properties=Excel 8.0;"
Dim conn As OleDbConnection = Nothing
Dim dt As System.Data.DataTable = Nothing
Dim excelDataSet As New DataSet()
Try
conn = New OleDbConnection(connString)
conn.Open() '<<< ERROR IS RAISED ON THIS LINE
dt = conn.GetOleDbSchemaTable(OleDbSchemaGuid.Tables, Nothing)
If dt Is Nothing Then
Return Nothing
End If
Dim excelSheets(dt.Rows.Count) As String
Dim i As Integer = 0
For Each row As DataRow In dt.Rows
excelSheets(i) = row("payments").ToString
System.Math.Min(System.Threading.Interlocked.Increment(i), i - 1)
If i = SheetNumber Then
Exit For
End If
Next
..................
I'm uploading to a shared server so don't have control as to permissions as such, but I do have read/write permissions and uploading Images works OK, but it's reading this file that I can't get to work.
NOTE
This error occurs with .xls files, when using .xlsx I get this error:
System.Data.OleDb.OleDbException (0x80004005): Cannot update. Database or object is read-only. at System.Data.OleDb.OleDbConnectionInternal
This error occurs on this line:
For Each row As DataRow In dt.Rows
So it appears it is uplpoading and opening the file OK, but not reading the rows....
I am not sure why that's happening either!
Any help would be much appreciated!

Answer 1

ACE is brutal, have troubles with it all the time and it cannot exist on a System in both 32 and 64 bit version at the same time. As a result I just dont use it at all.
To read an Excel XLSX file I use "EPPlus" which has proven to be very easy to deal with and extreamly efficient.
It ONLY works with XLSX (not XLS)
Example... (simple just pulls out first sheet as a datatable)
Public Function XlsxToDataTable(byteStream As IO.MemoryStream) As DataTable
Using pac As New OfficeOpenXml.ExcelPackage(byteStream)
Dim wb As OfficeOpenXml.ExcelWorkbook = pac.Workbook
Dim ws As OfficeOpenXml.ExcelWorksheet = wb.Worksheets(1) '1 based
Dim out As New DataTable
For iC As Integer = 1 To ws.Dimension.End.Column
out.Columns.Add(ws.Cells(1, iC).Value.ToString)
Next
For iR As Integer = 2 To ws.Dimension.End.Row
Dim nr As DataRow = out.NewRow
For iC As Integer = 1 To ws.Dimension.End.Column
nr(iC - 1) = ws.Cells(iR, iC).Value
Next
out.Rows.Add(nr)
Next
Return out
End Using
End Function