代码如下:
 /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();