//產(chǎn)生隨機驗證碼
        public static String getYangZhengMa()
        {
            String tempRsult = "";
            Random myRandom = new Random();
            for (int i = 0; i < 2; i++)
            {
                int myGetInt = myRandom.Next(65, 90);
                tempRsult += ((char)myGetInt).ToString();
            }
            return tempRsult;
        }

<input type="hidden" runat="server" id="hid_YanZhengMa" />

 if (!Page.IsPostBack)
 {

       this.hid_YanZhengMa.Value = System.mySQLConnection.AllText.getYangZhengMa();
       Session["YanZhengMa"] = this.hid_YanZhengMa.Value;

}

 protected void submit_jiaoFei_ServerClick(object sender, EventArgs e)
 {

         if (hid_YanZhengMa.Value.Trim() != ((String)Session["YanZhengMa"]))
        {
            MessageBox.alert(Page, "不能重復(fù)提交");
            return;
        }

}