防止刷新按钮提交

         界面放个隐藏控件hdfBtnRefran，

         /// <summary>
        /// 页面加载事件
        /// </summary>
        /// <param name="sender"></param>
        /// <param name="e"></param>
        protected void Page_Load(object sender, EventArgs e)
        {
            if (!IsPostBack)
            {
                //处理重复提交
                UpdateBtnState();
            }
        }

         /// <summary>
        /// 提交按钮事件
        /// </summary>
        /// <param name="sender"></param>
        /// <param name="e"></param>
        protected void btnSave_Click(object sender, EventArgs e)
        {

           //重复提交
            if (!Session["btnRef"].Equals(hdfBtnRefran.Value))
            {
                UpdateBtnState();
                return;
            }

           if (Page.IsValid)
            {

               UpdateBtnState();

            }

         }

        

        /// <summary>
        /// 更新提交按钮状态
        /// </summary>
        protected void UpdateBtnState()
        {
            hdfBtnRefran.Value = DateTime.Now.ToString("ffffff");
            Session["btnRef"] = hdfBtnRefran.Value;
        }