How do I get the first row in an excel workbook & save it to a new excel workbook using .net c#? I dont know the amount of columns so need to get entire row. This what I have but the new workbook is blank (no row copied)

Excel.Workbook xlWorkbook = xlApp.Workbooks.Open(file);    
Excel._Worksheet xlWorksheet = xlWorkbook.Sheets[1];    
Excel.Range xlRangeHeader = xlWorksheet.get_Range("A1", "A1").EntireRow;                         
Excel.Workbook xlWorkbookNew = xlApp.Workbooks.Add();    
Excel._Worksheet xlWorksheetNew = xlWorkbookNew.Sheets[1];    
xlWorksheetNew.get_Range("A1", "A1").EntireRow.Value = xlRangeHeader;                        
xlWorkbook.Close(false);                        
xlWorkbookNew.SaveAs(Path.Combine(sDestination, Path.GetFileName(file)), fileFormat);                        
xlWorkbookNew.Close(true);