Asp.net 模板下载和导入到DataTable中

HTML页面：

        <tr>
            <td colspan="" style="text-align: left; border: 1px;">
                <asp:FileUpload ID="FileUpload1" runat="server" CssClass="dfFile" Width="350px" />
                <asp:Button ID="btnImport" runat="server" Text="导入" CssClass="scbtn" OnClientClick="return LoadFile();"
                    OnClick="btnImport_Click" />
                <asp:Button ID="btnDownLoad" runat="server" Text="模板下载" CssClass="scbtn" OnClick="btnDownLoad_Click" />
            </td>
        </tr>

Asp.net后台：

    #region 导入
        /// <summary>
        /// 导入
        /// </summary>
        /// <param name="sender"></param>
        /// <param name="e"></param>
        protected void btnImport_Click(object sender, EventArgs e)
        {
            string IsXls = System.IO.Path.GetExtension(FileUpload1.FileName).ToString().ToLower();//获得文件的扩展名
            if (IsXls != ".xls" && IsXls != ".xlsx")
            {
                ShowMessageBox("只可以选择Excel文件");
                return;
            }
            HttpPostedFile file = this.FileUpload1.PostedFile;

            string filename = FileUpload1.FileName;              //获取Execle文件名
            string filePath = Server.MapPath("../StorageCheck/CheckUpFiles/" + FileUpload1.FileName);
            file.SaveAs(filePath);
            FileStream fs = new FileStream(filePath, FileMode.Open, FileAccess.Read);
            StreamReader sr = new StreamReader(fs, Encoding.GetEncoding("gb2312"));
            try
            {
                DataSet ds = ExcelSqlConnection(filePath, filename);  //调用自定义方法
                DataTable dt = ds.Tables[];

                //循环移除DataTable中的空行
                List<DataRow> removelist = new List<DataRow>();
                for (int i = ; i < dt.Rows.Count; i++)
                {
                    bool rowIsNull = true; //标记是否有空行
                    for (int j = ; j < dt.Columns.Count; j++)
                    {
                        if (!string.IsNullOrEmpty(dt.Rows[i][j].ToString().Trim()))
                        {

                            rowIsNull = false;
                        }
                    }
                    if (rowIsNull)
                    {
                        removelist.Add(dt.Rows[i]);
                    }
                }
                for (int i = ; i < removelist.Count; i++)
                {
                    dt.Rows.Remove(removelist[i]);
                }

                string detName = "";
                string detId = "";
                if (dt != null && dt.Rows.Count > )
                {
                    foreach (DataRow dr in dt.Rows)
                    {
                        detName += dr["箱号"].ToString() + "[" + dr["盒号"].ToString() + "]" + "[" + dr["起始卡号"].ToString() + "]" + "[" + dr["结束卡号"].ToString() + "]" +
                          "[" + dr["应有数量/张"].ToString() + "]" + "[" + dr["实际数量/张"].ToString() + "]" + "[" + dr["缺卡卡号"].ToString() + "];";
                        detId += dr["箱号"].ToString() + "," + dr["盒号"].ToString() + "," + dr["起始卡号"].ToString() + "," + dr["结束卡号"].ToString() + "," +
                                 dr["应有数量/张"].ToString() + "," + dr["实际数量/张"].ToString() + "," + dr["缺卡卡号"].ToString();

                        if (string.IsNullOrEmpty(dr["缺卡卡号"].ToString()))
                        {
                            detId += "" + ";";
                        }
                    }
                    hf_CheckId.Value = detId.TrimEnd(';');
                }
            }
            catch
            { }
            finally
            {
                fs.Flush(); //释放流
                fs.Close();//关闭流
            }
        }
        #endregion

        #region 模板下载
        /// <summary>
        /// 模板下载
        /// </summary>
        /// <param name="sender"></param>
        /// <param name="e"></param>
        protected void btnDownLoad_Click(object sender, EventArgs e)
        {
            //filePath为文件在服务器上的地址
            string excelFile = Server.MapPath("../StorageCheck/DownLoad/白卡入库导入模板.xls");
            FileInfo fi = new FileInfo(excelFile);
            HttpResponse contextResponse = HttpContext.Current.Response;
            contextResponse.Clear();
            contextResponse.Buffer = true;
            contextResponse.Charset = "GB2312"; //设置类型
            contextResponse.AppendHeader("Content-Disposition", String.Format("attachment;filename={0}", excelFile)); //定义输出文件和文件名
            contextResponse.AppendHeader("Content-Length", fi.Length.ToString());
            contextResponse.ContentEncoding = Encoding.Default;
            contextResponse.ContentType = "application/ms-excel";//设置输出文件类型为excel文件。 

            contextResponse.WriteFile(fi.FullName);
            contextResponse.Flush();
            contextResponse.End();
        }
        #endregion

        #region 读取Excel数据
        /// <summary>
        /// 读取Excel数据
        /// </summary>
        /// <param name="filepath">Excel服务器路径</param>
        /// <param name="tableName">Excel表名称</param>
        /// <returns></returns>
        public static System.Data.DataSet ExcelSqlConnection(string filepath, string tableName)
        {
            string strCon = "Provider=Microsoft.Jet.OLEDB.4.0;Data Source=" + filepath + ";Extended Properties='Excel 8.0;HDR=YES;IMEX=1'";
            OleDbConnection ExcelConn = new OleDbConnection(strCon);
            try
            {
                string strCom = string.Format("SELECT * FROM [Sheet1$]");
                //string strCom = "select * from [" + tableName + "]";
                ExcelConn.Open();
                OleDbDataAdapter myCommand = new OleDbDataAdapter(strCom, ExcelConn);
                DataSet ds = new DataSet();
                myCommand.Fill(ds, "[" + tableName + "$]");
                ExcelConn.Close();
                return ds;
            }
            catch
            {
                ExcelConn.Close();
                return null;
            }
        }
        #endregion