checkcode.aspx 生成随即验证码

checkcode.aspx 生成随即验证码

2008-06-23 16:49

using System; using System.Data; using System.Configuration; using System.Collections; using System.Web; using System.Web.Security; using System.Web.UI; using System.Web.UI.WebControls; using System.Web.UI.WebControls.WebParts; using System.Web.UI.HtmlControls; using System.Drawing; public partial class checkcode : System.Web.UI.Page {     protected void Page_Load(object sender, EventArgs e)     {         CreateCheckCodeImage(GenerateCheckCode());     }     private string GenerateCheckCode()     {         int number;         char code;         string checkCode = String.Empty;         System.Random random = new Random();         for (int i = 0; i < 4; i++)         {             number = random.Next();             if (number % 2 == 0)                 code = (char)('0' + (char)(number % 10));             else                 code = (char)('A' + (char)(number % 26));             checkCode += code.ToString();         }         Response.Cookies.Add(new HttpCookie("CheckCode", checkCode));         return checkCode;     }     private void CreateCheckCodeImage(string checkCode)     {         if (checkCode == null || checkCode.Trim() == String.Empty)             return;         System.Drawing.Bitmap image = new System.Drawing.Bitmap((int)Math.Ceiling((checkCode.Length * 12.5)), 22);         Graphics g = Graphics.FromImage(image);         try         {             //生成随机生成器             Random random = new Random();             //清空图片背景色             g.Clear(Color.White);             //画图片的背景噪音线             for (int i = 0; i < 2; 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.Black), x1, y1, x2, 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(checkCode, 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();             image.Save(ms, System.Drawing.Imaging.ImageFormat.Gif);             Response.ClearContent();             Response.ContentType = "image/Gif";             Response.BinaryWrite(ms.ToArray());         }         finally         {             g.Dispose();             image.Dispose();         }     } }