asp.net如何读取Excel文件

using System;
using System.Collections.Generic;
using System.Linq;
using System.Web;
using System.Web.UI;
using System.Web.UI.WebControls;
using System.Data.OleDb;
using System.Data;
using System.Text;

　　　/// <summary>
        /// 读取Excel文件
        /// </summary>
        /// <param name="sender"></param>
        /// <param name="e"></param>
        protected void btnImport_Click(object sender, EventArgs e)
        {

　　　　string filename = DateTime.Now.ToString("yyyyMMdd") + ".xls";
            string fileSavePath = Server.MapPath("~/Exc/") + filename;
            TxtFileDown.SaveAs(fileSavePath);
            string strConn = "Provider=Microsoft.Jet.OLEDB.4.0;Data Source=" + fileSavePath + ";Extended Properties=Excel 8.0";
            OleDbConnection cnnxls = new OleDbConnection(strConn);
            OleDbDataAdapter oda = new OleDbDataAdapter(string.Format("select [工号] as UserNo,[时间] as ClockTime,'{0}' as fromfile,[地点] as ClockAdds from [Sheet1$]", filename), cnnxls);
            DataSet ds = new DataSet();
            try
            {
                oda.Fill(ds, "Sheet1$");
                cnnxls.Close();
                int i = ds.Tables["Sheet1$"].Rows.Count;
            }
            catch(Exception ex)
            {
                //throw ex;
                Message("请将待导入数据的Excel表格的Sheet名称命名为Sheet1", true);
                cnnxls.Close();
                return;
            }

　　}