验证码代码

验证码代码 public string RandomNum(int n) { string strchar = "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,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 = strchar.Split(','); string VNum = ""; int temp = -1; Random rand = new Random(); for (int i = 1; i < n + 1; i++) { if (temp != -1) { rand = new Random(i * temp * unchecked((int)DateTime.Now.Ticks)); } int t = rand.Next(61); if (temp != -1 && temp == t) { return RandomNum(n); } temp = t; VNum += VcArray[t]; } return VNum; } public void CheckCodes(string CheckCode) { Random rand = new Random(); int iwidth = (int)(CheckCode.Length * 15); System.Drawing.Bitmap image = new System.Drawing.Bitmap(iwidth, 22); Graphics g = Graphics.FromImage(image); g.Clear(Color.White); //画图片的背景噪音线20条 for (int i = 0; i < 20; i++) { int x1 = rand.Next(image.Width); int x2 = rand.Next(image.Width); int y1 = rand.Next(image.Height); int y2 = rand.Next(image.Height); g.DrawLine(new Pen(Color.Silver), x1, x2, y1, y2); } //定义颜色 Color[] c = { Color.Black, Color.Red, Color.DarkBlue, Color.Green, Color.Orange, Color.Brown, Color.DarkCyan, Color.Purple, Color.YellowGreen }; //定义字体 string[] font = { "Verdana", "Microsoft Sans Serif", "Comic Sans MS", "Arial", "宋体", "新宋体" }; //随机输出噪点 for (int i = 0; i < 50; i++) { int x = rand.Next(image.Width); int y = rand.Next(image.Height); g.DrawRectangle(new Pen(Color.LightGray, 0), x, y, 1, 1); } //输出不同字体和颜色的验证码字符 for (int i = 0; i < CheckCode.Length; i++) { int cindex = rand.Next(7); int findex = rand.Next(6); Font f = new System.Drawing.Font(font[findex], 12, System.Drawing.FontStyle.Bold); Brush b = new System.Drawing.SolidBrush(c[cindex]); int ii = 4; if ((i + 1) % 2 == 0) { ii = 2; } g.DrawString(CheckCode.Substring(i, 1), f, b, 3 + (i * 12), ii); } //画一个边框 g.DrawRectangle(new Pen(Color.Black, 0), 0, 0, image.Width - 1, image.Height - 1); //输出到浏览器 System.IO.MemoryStream ms = new System.IO.MemoryStream(); image.Save(ms, System.Drawing.Imaging.ImageFormat.Gif); HttpContext.Current.Response.ClearContent(); //Response.ClearContent(); HttpContext.Current.Response.ContentType = "image/Png"; HttpContext.Current.Response.BinaryWrite(ms.ToArray()); g.Dispose(); image.Dispose(); }