Convert xls to xlsx without interop

Question

I have a computer(actually several machines) on my companies network that do not have office installed. I need to develop a vb.net program that will parse information from a spreadsheet which is usually in an .xls format. I don't feel that there are many options for reading data from an .xls document without the interop. If so what are some options?

If I could even convert an .xls to .xlsx programmatically without the interop, that would be an option too. I could then use ClosedXML to parse from a xlsx. Or is there a way to read an .xls file with ClosedXML that I'm not seeing?

Any help would be great as I am having trouble finding the answer to this one.

Answer 1

You don't need to use com interop to read from an Excel file. You can use OleDb (although you might need to install the office data connectivity components)

Imports System.Data.OleDb:

Public Shared Function ReadExcelWorkSheet(ByVal sheetName As String, ByVal connectionString As String) As DataTable
    Dim sql As String = String.Format("SELECT * FROM [{0}$]", sheetName)
    Dim dt = New DataTable()

    Using conn As OleDbConnection = New OleDbConnection(connectionString)
        Using cmd = New OleDbCommand(sql, conn)
            conn.Open()
            Using adapter = New OleDbDataAdapter(cmd)
                adapter.Fill(dt)
            End Using
        End Using
        conn.Close()
    End Using
    Return dt
End Function

Where connection string is for xlsx files:

Provider=Microsoft.ACE.OLEDB.12.0;Data Source=c:\myFolder\myExcel2007file.xlsx;Extended Properties="Excel 12.0 Xml;HDR=YES";

or for xls files:

Provider=Microsoft.ACE.OLEDB.12.0;Data Source=c:\myFolder\myOldExcelFile.xls;Extended Properties="Excel 8.0;HDR=YES";

more info on the connection strings here

Answer 2

You can read it via ADO.Net. I'd need to see your existing code, but this should allow you to open it without Excel.

System.Data.OleDb.OleDbConnection("Provider=Microsoft.ACE.OLEDB.12.0;Data Source=c:\myFolder\myExcel2007file.xlsx;
Extended Properties='Excel 12.0 Xml;HDR=YES';")