NPOI-读取已有Excel文件

WorkbookFactory.Create（）函数读取已存在文件；
单个Cell有多个格式数据，读取之前确认要读取的是哪一种格式；
假如cell里面我敲了一串string进去，然后在代码里面用Cell.NumericCellValue来读取的话，就会崩掉；

 public static void GetDataFromExcel(string path)
        {
            IWorkbook excel = WorkbookFactory.Create(path);
            ISheet sheet1 = excel.GetSheetAt(0);
            IRow row_num1 = sheet1.GetRow(0);
            IRow row_num2 = sheet1.GetRow(1);
            for (int i = 0; i < 10; i++)
            {
                ICell cell = row_num2.Cells[i];
                Console.WriteLine(cell.StringCellValue);
                //ICell tempCell = row_num1.Cells[i];
                //Console.WriteLine(tempCell.NumericCellValue);

                //  row_num2.CreateCell(i).SetCellValue(Convert.ToInt32( tempCell.StringCellValue)*2);
            }
        }