ASP.NET 导入Excel数据，量大时，导入慢的有关问题

ASP.NET 导入Excel数据，量大时，导入慢的问题？
以下是我的导入代码，当Excel数据为1000条时，导入就要20秒，请问下面写法有什么改进，能让时间缩短？求高手解答？

try

            {

                string fileName = excelUploadUrl;

                Microsoft.Office.Interop.Excel.Application excel = new Microsoft.Office.Interop.Excel.Application();

                object oMissing = System.Reflection.Missing.Value;

                excel.Application.Workbooks.Open(fileName, oMissing, oMissing, oMissing, oMissing, oMissing, oMissing, oMissing, oMissing, oMissing, oMissing, oMissing, oMissing, oMissing, oMissing);

                Microsoft.Office.Interop.Excel.Workbook book = excel.Workbooks[1];

                Microsoft.Office.Interop.Excel.Worksheet sheet = (Microsoft.Office.Interop.Excel.Worksheet)excel.Worksheets[1];


                string strSheetName = sheet.Name;

                string strConn = "Provider=Microsoft.Jet.OLEDB.4.0;Data Source = " + fileName + ";Extended Properties ='Excel 8.0;HDR=NO;IMEX=1'";

                string strExcel = "select * from  [" + strSheetName + "$]";

                DataSet ds = new DataSet();

                OleDbConnection conn = new OleDbConnection(strConn);

                conn.Open();

                OleDbDataAdapter adapter = new OleDbDataAdapter(strExcel, conn);

                adapter.Fill(ds);

                DataRow[] dr = ds.Tables[0].Select();

                int ss = ds.Tables[0].Rows.Count;

                int rowsnum = ds.Tables[0].Rows.Count;

                if (rowsnum == 0)

                {

                    return Json(new OperateReturnInfo(OperateCodeEnum.Failed, "导入失败！Excel表为空表,无数据！"), JsonRequestBehavior.AllowGet);

                }

                //检查门店编码是否存在

                bool IsExist = false;

                for (int i = 1; i < rowsnum; i++)

                {

                    bool result = StoreIPManager.CheckStoreCode(dr[i][0].ToString());

                    if (result)

                    {

                        IsExist = true;

                        return Json(new OperateReturnInfo(OperateCodeEnum.Failed, "导入失败！门店编码'" + dr[i][0].ToString() + "'已经存在，请修改后再重新导入！"), JsonRequestBehavior.AllowGet);

                    }

                }

                //全部核查通过,执行插入数据库

                if (!IsExist)

                {