public void GenerateMultipSheetReport_Test() { var columnDefs = CreateMasterDetailDataColumns().Where(c => c is ColumnDef <Order>).Cast <ColumnDef <Order> >().ToArray(); List <Order> orders = CreateOrdersWithDetails(); var columnDetialDefs = CreateMasterDetailDataColumns().Where(c => c is ColumnDef <OrderDetail>).Cast <ColumnDef <OrderDetail> >().ToArray(); var details = orders[0].Details; ReportBuilder builder = new ReportBuilder(); Stream stream = builder.AddSheet(orders, columnDefs) .AddSheet(details, columnDetialDefs) .Build(); ValidateSpreadsheetDoc(stream); DumpToFile(stream, @"target5.xlsx"); }