owc图片文件改变，页面图片不会变
 protected void ss_Click(object sender, EventArgs e)
    {
        System.IO.File.Delete(MapPath("./ShowData1.gif"));
        string tj1 = BeginTime.Text.Trim();
        string tj2 = EndTime.Text.Trim();
        string tj3 = xq_name.Text.Trim();
        string tj4;
        //File.Delete(MapPath("文件路径"))
        //string deleteFileName = "./ShowData.gif";

        if (tj1 != "" && tj2 != "" && tj3 != "")
        {
           
            string strSeriesName = "图例";
            string ConnectString = "server=10.81.198.238;uid=gaohanying;pwd=123456;database=master";
            //string Sqk = "select wd_id from wdyl_chazhibiao where xq_name='+tj3+'";
            string Sqk = "SELECT wd_id FROM wdyl_chazhibiao WHERE xq_name = '" + tj3 + "'";
            //string Sql = "select wendu1 ,riqi from shishi3  where riqi>='" + tj1 + "'and  riqi<='" + tj2 + "'";

            SqlConnection myConn = new SqlConnection(ConnectString);
            myConn.Open();
            SqlCommand cmd = new SqlCommand(Sqk, myConn);
            SqlDataReader dr = cmd.ExecuteReader();
            DataSet ds = new DataSet();

            if (dr.Read())
            {
               
               
            }
             
            tj4 = dr["wd_id"].ToString();
            string Sql = "select "+tj4+",riqi from shishi3  where riqi>='" + tj1 + "'and  riqi<='" + tj2 + "'";
            dr.Close();//关闭
            dr.Dispose();//释放