.net生成CSV

SqlConnection   conn=new   SqlConnection(System.Configuration.ConfigurationSettings.AppSettings["conn"]);    
        SqlDataAdapter   da=new   SqlDataAdapter("select   *   from   tb1",conn);    
        DataSet   ds=new   DataSet();    
        da.Fill(ds,"table1");    
        DataTable   dt=ds.Tables["table1"];    
        string   name=System.Configuration.ConfigurationSettings.AppSettings["downloadurl"].ToString()+DateTime.Today.ToString("yyyyMMdd")+new   Random(DateTime.Now.Millisecond).Next(10000).ToString()+".csv";//存放到web.config中downloadurl指定的路径，文件格式为当前日期+4位随机数    
        FileStream   fs=new   FileStream(name,FileMode.Create,FileAccess.Write);    
        StreamWriter   sw=new   StreamWriter(fs,System.Text.Encoding.GetEncoding("gb2312"));    
        sw.WriteLine("自动编号,姓名,年龄");    
        foreach(DataRow   dr   in   dt.Rows)    
        {    
          sw.WriteLine(dr["ID"]+","+dr["vName"]+","+dr["iAge"]);    
        }    
        sw.Close();