asp.new 验证码

来源：互联网发布：神经网络算法编辑：程序博客网时间：2024/06/08 03:04

    <form id="form1" runat="server">    <div>            <asp:Image ID="Image1" imageUrl="~/WebForm1.aspx?action=create"   runat="server" />        </div>    </form>

        protected void Page_Load(object sender, EventArgs e)        {            if (!IsPostBack)            {                if (Request.QueryString["action"] == "create")                {                    string validateNum = CreateRandomNum(4);                    CreateImage(validateNum);                    Session["ValidateNum"] = validateNum;                }            }        }        //生产随机数        private string CreateRandomNum(int NumCount)        {            string allChar = "0,1,2,3,4,5,6,7,8,9,A,B,C,D,E,F,G,H,I,J,K,O,P,Q,R,S,T,U,W,X,Y,Z,a,b,c,d,e,f,g,h,i,j,k,m,n,o,p,q,s,t,u,w,x,y,z";            string[] allCharArray = allChar.Split(',');//拆分成数组            string randomNum = "";            int temp = -1;                             //记录上次随机数的数值，尽量避免产生几个相同的随机数            Random rand = new Random();            for (int i = 0; i < NumCount; i++)            {                if (temp != -1)                {                    rand = new Random(i * temp * ((int)DateTime.Now.Ticks));                }                int t = rand.Next(35);                if (temp == t)                {                    return CreateRandomNum(NumCount);                }                temp = t;                randomNum += allCharArray[t];            }            return randomNum;        }        //生产图片        private void CreateImage(string validateNum)        {            if (validateNum == null || validateNum.Trim() == string.Empty)                return;            //生成BitMap图像            System.Drawing.Bitmap image = new System.Drawing.Bitmap(validateNum.Length * 12 + 12, 22);            Graphics g = Graphics.FromImage(image);            try            {                //生成随机生成器                Random random = new Random();                //清空图片背景                g.Clear(Color.White);                //画图片的背景噪音线                for (int i = 0; i < 25; i++)                {                    int x1 = random.Next(image.Width);                    int x2 = random.Next(image.Width);                    int y1 = random.Next(image.Height);                    int y2 = random.Next(image.Height);                    g.DrawLine(new Pen(Color.Silver), x1, x2, y1, y2);                }                Font font = new System.Drawing.Font("Arial", 12, (System.Drawing.FontStyle.Bold | System.Drawing.FontStyle.Italic));                System.Drawing.Drawing2D.LinearGradientBrush brush = new System.Drawing.Drawing2D.LinearGradientBrush(new Rectangle(0, 0, image.Width, image.Height), Color.Blue, Color.DarkRed, 1.2f, true);                g.DrawString(validateNum, font, brush, 2, 2);                //画图片的前景噪音点                for (int i = 0; i < 100; i++)                {                    int x = random.Next(image.Width);                    int y = random.Next(image.Height);                    image.SetPixel(x, y, Color.FromArgb(random.Next()));                }                //画图片的边框线                g.DrawRectangle(new Pen(Color.Silver), 0, 0, image.Width - 1, image.Height - 1);                System.IO.MemoryStream ms = new System.IO.MemoryStream();                //将图像保存到指定流                image.Save(ms, System.Drawing.Imaging.ImageFormat.Gif);                Response.ClearContent();                Response.ContentType = "image/Gif";                Response.BinaryWrite(ms.ToArray());            }            finally            {                g.Dispose();                image.Dispose();            }        }

0 0