用DataSet导出到Excel

//读取临时文件
   GYYW.DA.Common.Base_SqlDataBase daBZDM = new GYYW.DA.Common.Base_SqlDataBase();
   DataSet dsBZDM = daBZDM.GetDataSetBySql("select QCDM,MC,GG from WG_BZDM where QCDM like '02%'");

   //同时将虚拟目录下的Data作为临时文件目录。
   string urlPath = HttpContext.Current.Request.ApplicationPath + "/Data/";
   string physicPath = HttpContext.Current.Server.MapPath(urlPath);
   //string fileName = Guid.NewGuid() + ".Xls";
   string fileName ="DownLoad.Xls";
   string connString = "Provider=Microsoft.Jet.OLEDB.4.0;Data Source=" + physicPath + fileName +";Extended Properties=Excel 8.0;";

   OleDbConnection objConn = new OleDbConnection(connString);
   OleDbCommand objCmd = new OleDbCommand();
   objCmd.Connection = objConn;
   objCmd.Connection.Open();

   //建立表结构
   objCmd.CommandText = @"CREATE TABLE Sheet1(器材代码 varchar,名称 varchar, 规格 varchar)";
   objCmd.ExecuteNonQuery();

   //建立插入动作的Command

   objCmd.CommandText = "INSERT INTO Sheet1(器材代码, 名称,规格) VALUES (@QCDM, @MC, @GG)";

   objCmd.Parameters.Clear();

   objCmd.Parameters.Add(new OleDbParameter("@QCDM", OleDbType.VarChar));
   objCmd.Parameters.Add(new OleDbParameter("@MC", OleDbType.VarChar));
   objCmd.Parameters.Add(new OleDbParameter("@GG",OleDbType.VarChar));
 
   //遍历DataSet将数据插入新建的Excel文件中
   foreach (DataRow row in dsBZDM.Tables[0].Rows)
   {   
    for (int i=0; i<objCmd.Parameters.Count; i++)
    {
     objCmd.Parameters[i].Value = row[i];
    }
    objCmd.ExecuteNonQuery();
   }
   objCmd.Connection.Close();

   //提供下载
   //清除临时文件
   HttpResponse response = HttpContext.Current.Response;
   response.Clear();
   //为输出作准备
   response.WriteFile(urlPath + fileName);
   string httpHeader="attachment;filename=KCMX.Xls";
   response.AppendHeader("Content-Disposition", httpHeader);
   response.Flush();
   //输出完毕后清除临时文件
   string strSaveDir = "../Data/";
   string strFile = Server.MapPath(strSaveDir + fileName).ToString();
   //string sss = urlPath + fileName;
   System.IO.File.Delete(strFile);//删除临时文件
   response.End();