/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();