算法验证码

protected void (object sender, EventArgs e)
{
	Color[] color = { Color.Black, Color.Red, Color.Blue, Color.Brown, Color.DarkBlue, Color.Yellow, Color.Green };
        string[] font = { "宋体", "新宋体", "幼圆", "楷体_GB2312", "黑体", "隶书" };
        int[] fontsize = { 20, 40 };
        int[] shuzi = { 0, 1, 2, 3, 4, 5, 6, 7, 8, 9 };
        int[] shuzi2 = { 0, 1, 2, 3, 4, 5, 6, 7, 8, 9 };

        string[] fuhao = { "+", "*" };

        Random rnd = new Random();
        string fuhao1 = fuhao[rnd.Next(fuhao.Length)];
        int chkCode = shuzi[rnd.Next(shuzi.Length)];
        int chkCode2 = shuzi2[rnd.Next(shuzi2.Length)];
        Bitmap bmp = new Bitmap(200, 100);
        Graphics g = Graphics.FromImage(bmp);
        g.Clear(Color.WhiteSmoke);

        string f = fuhao1;
        Session["ValidateCode3"] = f;
        int s = chkCode;
        int s2 = chkCode2;


        if (fuhao1.ToString() == "+")
        {
            int sum = chkCode + chkCode2;
            Session["ValidateCode1"] = sum;

        }
        else
        {
            int chengji = chkCode * chkCode2;
            Session["ValidateCode1"] = chengji;
        }
        for (int i = 0; i < 1; i++)
        {
            string num = shuzi[rnd.Next(shuzi.Length)].ToString();
            int fnts = fontsize[rnd.Next(fontsize.Length)];
            Font ft = new Font(num, fnts);
            Color clr = color[rnd.Next(color.Length)];
            g.DrawString(chkCode + fuhao1 + chkCode2 + "=?", ft, new SolidBrush(clr), (float)i * 10, (float)30);
        }

        for (int i = 0; i < 30; i++)
        {
            int x = rnd.Next(bmp.Width);
            int y = rnd.Next(bmp.Height);
            Color clr = color[rnd.Next(color.Length)];
            bmp.SetPixel(x, y, clr);
        }

        Response.Buffer = true;
        Response.BufferOutput = true;
        Response.Cache.SetExpires(DateTime.Now.AddMilliseconds(-1));
        Response.Cache.SetCacheability(HttpCacheability.NoCache);

        Response.ExpiresAbsolute = System.DateTime.Now.AddMilliseconds(0);
        Response.Expires = 0;
        Response.CacheControl = "no-cache";
        Response.AppendHeader("Pragma", "No-Cache");
        MemoryStream ms = new MemoryStream();
        try
        {
            bmp.Save(ms, ImageFormat.Png);
            Response.ClearContent();
            Response.ContentType = "image/Png";
            Response.BinaryWrite(ms.ToArray());
        }
        finally
        {
            bmp.Dispose();
            g.Dispose();
        }
}