// ajax 控制图像的变化
        protected void imgbtnCanNull_Click(object sender, ImageClickEventArgs e)
        {
            ImageButton ibtn    = sender as ImageButton;
            string      imgurl  = ibtn.ImageUrl;
            string      imgName = imgurl.Substring(imgurl.LastIndexOf('/') + 1, imgurl.Length - imgurl.LastIndexOf('.') - 1);

            if (imgName == "yes")
            {
                ibtn.ImageUrl = "~/Images/no.gif";
            }
            else
            {
                ibtn.ImageUrl = "~/Images/yes.gif";
            }
            int      sid    = DataConverter.CLng(ibtn.CommandArgument);
            M_Survey survey = (new B_Survey()).SelReturnModel(sid);

            survey.IsOpen = !survey.IsOpen;
            surBll.UpdateSurvey(survey);
        }