public void ConvertXlsInCSV(string way, string filename, string typeFile,string tableName, int worksheetNumber)
        {

            var DataTableConnect = CreateConnectExcelStrBuilder(way, filename, typeFile, "NO", true, true);
            using (OleDbConnection connection = new OleDbConnection(DataTableConnect.Item2.ConnectionString))
            {
                // get schema, then data
                var dt = new DataTable();
                try
                {
                    connection.Open();
                    var schemaTable = connection.GetOleDbSchemaTable(OleDbSchemaGuid.Tables, null);
                    if (schemaTable.Rows.Count < worksheetNumber) throw new ArgumentException("The worksheet number provided cannot be found in the spreadsheet");
                    string worksheet = schemaTable.Rows[worksheetNumber - 1]["table_name"].ToString().Replace("'", "");
                    string sql = String.Format("select * from [{0}]", worksheet);
                    var da = new OleDbDataAdapter(sql, connection);
                    da.Fill(dt);
                }
                catch (Exception e)
                {
                    // ???
                    throw e;
                }
                finally
                {
                    connection.Close();
                }

                // write out CSV data
                using (var wtr = new StreamWriter(way + filename + "." + "csv"))
                {
                    foreach (DataRow row in dt.Rows)
                    {
                        bool firstLine = true;
                        foreach (DataColumn col in dt.Columns)
                        {
                            if (!firstLine) { wtr.Write(","); } else { firstLine = false; }
                            var data = row[col.ColumnName].ToString().Replace("\"", "\"\"");
                            wtr.Write(String.Format("\"{0}\"", data));
                        }
                        wtr.WriteLine();
                    }
                }
            }

        }