在 C# 窗口窗体中推 EPPlus 无法在 excel 文件中获取自动填充值

Question

** C# 窗体中的 EPPlus 无法在 excel 文件中获取自动填充值。

错误消息：System.NullReferenceException：“对象引用未设置为 object 的实例。” OfficeOpenXml.ExcelRangeBase.Value.get 返回 null。

这是我的代码请帮助我**

 private void btn_Import_Click(object sender, EventArgs e)
    {
        ExcelPackage.LicenseContext = LicenseContext.NonCommercial;
        List<UserInfo> userList = new List<UserInfo>();
        try
        {
            //Open File Excel
            var package = new ExcelPackage(new FileInfo("Thang1.xlsx"));
            ExcelWorksheet worksheet = package.Workbook.Worksheets[1];
            for (int i = worksheet.Dimension.Start.Row + 1; i <= worksheet.Dimension.End.Row; i++)
            {
                try
                {
                    int j = 1;
                    string SoCC = worksheet.Cells[i, j++].Value==null? string.Empty : worksheet.Cells[i,j++].Value.ToString();
                    string Ngay = worksheet.Cells[i, j++].Value == null ? string.Empty : worksheet.Cells[i, j++].Value.ToString();
                    string ThongTin = worksheet.Cells[i, j++].Value == null ? string.Empty : worksheet.Cells[i, j++].Value.ToString();
                    string PhanLoai = worksheet.Cells[i, j++].Value == null ? string.Empty : worksheet.Cells[i, j++].Value.ToString();
                    string Hoten = worksheet.Cells[i, j++].Value;
                    string Phi = worksheet.Cells[i, j++].Value;
                    UserInfo user = new UserInfo()
                    {
                        SoccHS = SoCC,
                        NgayHS = Ngay,
                        ThongTinHS = ThongTin,
                        PhanLoaiHS = PhanLoai,
                        HotenHS = Hoten,
                        PhiHS = Phi,
                    };
                    userList.Add(user);



                }
                catch (Exception exe)
                {
                    
                }

            }
        }
        catch (Exception ee)
        {
            MessageBox.Show("Error!");
        }
        dtg_Excel.DataSource = userList;
    }