关于更换验证码图片不刷新页面问题

先在Image.aspx中 写验证图片代码

在.CS文件中

 

    public class image : System.Web.UI.Page
    ...{
        private void Page_Load(object sender, System.EventArgs e)
        ...{
                string tmp = RndNum(4);
            HttpCookie a = new HttpCookie("ImageV",tmp);   
            Response.Cookies.Add(a);
            this.ValidateCode(tmp);
        }
        private void ValidateCode(string VNum) 
        ...{
            Bitmap Img=null;
            Graphics g=null;
            MemoryStream ms=null;

            int gheight=VNum.Length*12;
            Img=new Bitmap(gheight,25);
            g=Graphics.FromImage(Img);
            //背景颜色
            g.Clear(Color.White);
            //文字字体
            Font f=new Font("Arial ",10);
            //文字颜色
            SolidBrush s=new SolidBrush(Color.Black);
            g.DrawString(VNum,f,s,3,3);
            ms=new MemoryStream();
            Img.Save(ms,ImageFormat.Jpeg);
            Response.ClearContent(); 
            Response.ContentType="image/Jpeg";
            Response.BinaryWrite(ms.ToArray());
   
            g.Dispose();
            Img.Dispose();
            Response.End();
        }

        private string RndNum(int VcodeNum)
        ...{
            string Vchar="0,1,2,3,4,5,6,7,8,9,a,b,c,d,e,f,g,h,i,j,k,l,m,n,o,p"+
                ",q,r,s,t,u,v,w,x,y,z";
            string[] VcArray=Vchar.Split(new Char [] ...{','});
            string VNum="";
            int temp=-1;

            Random rand=new Random();
   
            for(int i=1;i<VcodeNum+1;i++)
            ...{
                if(temp!=-1)
                ...{
                    rand=new Random(i*temp*unchecked((int)DateTime.Now.Ticks));
                }
   
                int t=rand.Next(35);
                if(temp!=-1&&temp==t)
                ...{
                    return RndNum(VcodeNum);
                }
                temp=t;
                VNum+=VcArray[t];
            }
            return VNum;
        }

然后在注册页面中写Javascript脚本

 

        <script language="javascript" type="text/javascript">
        
        
        function reloadimage(url)
        ...{
            document.Form_RegisterBaseInfo.img1.src=url;
        }
            </script>

 

再在页面中写超链接<A>……

 

<A href="javascript:reloadimage('image.aspx?'+Math.random())">
   <IMG id="img1" style="WIDTH: 64px; HEIGHT: 30px" height="30" alt="更换验证码" src="image.aspx" width="64"   border="0">
</A>

 

这里主要在调用Image.aspx时通过调用Math.random()函数随机产生图片