2010.6.10 生成验证码的方法
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public void ProcessRequest(HttpContext context)
{ string checkCode = GenCode(5); context.Session["Code"] = checkCode; System.Drawing.Bitmap image = new System.Drawing.Bitmap(70, 22); Graphics g = Graphics.FromImage(image); try { Random random = new Random(); g.Clear(Color.White); int i; for (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, y1, x2, y2); } Font font = new System.Drawing.Font("Arial", 12, (System.Drawing.FontStyle.Bold)); 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); 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); context.Response.ClearContent(); context.Response.ContentType = "image/Gif"; context.Response.BinaryWrite(ms.ToArray()); } finally { g.Dispose(); image.Dispose(); } } private string GenCode(int num) { string str = "0123456789ABCDEFGHIJKLMNOPQRSTUVWXYZ"; char[] chastr = str.ToCharArray(); string code = ""; Random rd = new Random(); int i; for (i = 0; i < num; i++) { code += str.Substring(rd.Next(0, str.Length), 1); } return code; } public bool IsReusable { get { return false; } }