NPOI支持excel2003和excel2007

  IWorkbook wk = null;

 if (filePath.ToLower() == ".xls")

 {

    wk = new HSSFWorkbook(fs);

 }

 else

 {

   wk = new XSSFWorkbook(fs);

 }
                      

ps:对象HSSFWorkbook支持excel2003

　  对象HSSFWorkbook支持excel2007