当用户更换验证码的时候怎么样保存当前页面空间的状态？

Question

     当前有TEXTBOX， RadioButtonList等控件， 主要是当用户点击刷新验证码时 页面的各个空间的都会消失，我想保存其中的值，请各位大虾指教啊。最好有示例代码哦

Answer 1

验证码页<tr>
                                                                                <td height="20" width="60" class="text6">
                                                                                    验证码：</td>
                                                                                <td align="left">
                                                                                    <input type="text" autocomplete="off" class="input4" style="width: 60px;" name="textfield"
                                                                                        id="Text_num" runat="server" size="8" maxlength="4" />&nbsp;<a href="javascript:newVCode();"><img
                                                                                            alt="点击刷新验证码" title="点击刷新验证码" border="0" id="vcode" height="21" width="74" src="../sub/GetVCode.aspx"
                                                                                            tabindex="0" /></a></td>
                                                                            </tr>
    <script type="text/javascript" language="javascript">function newVCode()
{

url="../sub/GetVCode.aspx?updatetime="+Math.random();
document.getElementById("vcode").src=url;
document.getElementById("Text_num").select();
}

    </script>验证码。cs//验证码
        if (Session["Num"] == null)
        {
            lblmsg.Text = "<script language='javascript'>alert('请重新输入验证码！')</script>";
            Text_num.Value = "";
            Text_num.Focus();
            return;
        }
        string strNum = Session["Num"].ToString().ToLower();
        if (this.Text_num.Value.ToLower() != strNum)
        {
            lblmsg.Text = "<script language='javascript'>alert('验证码不正确！');</script>";
            //lblmsg.Text = "setFocus('" + Text3.ClientID + "')";
            this.Text_num.Value = "";
            this.Text_num.Focus();
            return;
        }GetVCode.aspx
建立个空页面就可以
GetVCode.aspx.csusing System.Drawing.Imaging;
using System.IO;protected void Page_Load(object sender, EventArgs e)
    {
        //创建随机数
string strNum = Rndnum();
Session["Num"]=strNum;
ValidateCode(strNum);
    }
    public string Rndnum()
    {
        int j1;
        string strChoice = "2,3,4,5,6,7,8,9,a,b,c,d,e,f,g,h,j,k,m,n,p,q,r,s,t,u,v,w,x,y,z";
        string[] strResult = strChoice.Split(',');
        string strReturn = "";
        Random rnd = new Random(unchecked((int)DateTime.Now.Ticks));
        for (int i = 0; i < 4; i++)
        {
            Random rnd1 = new Random(rnd.Next() * unchecked((int)DateTime.Now.Ticks));
            j1 = rnd1.Next(31);
            rnd = new Random(rnd.Next() * unchecked((int)DateTime.Now.Ticks));
            strReturn = strReturn + strResult[j1].ToString();
        }
        return strReturn.ToUpper();
    }
    public void ValidateCode(string vnum)
    {
        MemoryStream ms = new MemoryStream();
        double Height = (vnum.Length) * 13;
        int gHeight = Convert.ToInt32(Height);
        Bitmap img = new Bitmap(gHeight, 20);
        Pen p1 = new Pen(Color.Black, 0);
        Graphics g = Graphics.FromImage(img);
        g.Clear(Color.White);
        Random rnd1 = new Random();        //画随机背景        //for (int i = 0; i < 30; i++)
        //{
        //    if (i % 3 == 0)//画点
        //    {
        //        int x1 = rnd1.Next(img.Width);
        //        int y1 = rnd1.Next(img.Height);        //        g.DrawRectangle(p1, x1, y1, 1, 1);        //    }
        //}
        //画图片的前景噪音点
        for (int i = 0; i < 20; i++)
        {
            int x = rnd1.Next(img.Width);
            int y = rnd1.Next(img.Height);            img.SetPixel(x, y, Color.FromArgb(rnd1.Next()));
        }
        //画一个边框
        //g.DrawRectangle(new Pen(Color.PowderBlue,0),0,0,img.Width-1,img.Height-1);
        //画验证码字母        string[] font = { "Sydnie", "Microsoft Sans Serif" };//定义字体             int fontnum = rnd1.Next(2);        Font f1 = new Font(font[fontnum], 10, FontStyle.Regular);
        for (int i = 0; i < vnum.Length; i++)
        {
            fontnum = rnd1.Next(2);
            int y = rnd1.Next(4);
            switch (fontnum)
            {                //case 2:
                //    f1 = new Font(font[fontnum], 11, FontStyle.Italic);
                //    g.DrawString(vnum.Substring(i, 1), f1, (new SolidBrush(Color.Blue)), i * 11, y);
                //    break;                default:
                    f1 = new Font(font[fontnum], 11, FontStyle.Regular);
                    g.DrawString(vnum.Substring(i, 1), f1, (new SolidBrush(Color.Blue)), i * 11, y);
                    break;            }        }
        //输出到浏览器
        img.Save(ms, ImageFormat.Png);
        Response.ClearContent();
        Response.ContentType = "image/Bmp";
        Response.BinaryWrite(ms.ToArray());
        g.Dispose();
        Response.End();
    }通过在GetVCode.aspx 生成Session["Num"] 保存验证码，在验证码页验证用户输入值是否等于Session["Num"] 
这种方法可以不刷新页面