<img οnclick="this.src='ValidateCode.ashx?_='+Math.random()" title="看不清？" style="cursor:pointer" src="ValidateCode.ashx" />
<input type="text" name="txtCode" /><br /> <input type="submit" />
、、、、、、、、、、、、、、、、、、、、、、、、、、、、、、、、、、、、、、、、、、、、、
<%@ WebHandler Language="C#" class="ValidateCode" %>using System;using System.Web;using System.Drawing;using System.Web.SessionState;public class ValidateCode : IHttpHandler,IRequiresSessionState { public void ProcessRequest(HttpContext context) { context.Response.ContentType = "image/jpeg"; string code = GetRndStr(); context.Session["code"] = code; using (Bitmap img = CreateImages(code, "ch")) { img.Save(context.Response.OutputStream, System.Drawing.Imaging.ImageFormat.Jpeg); } } public bool IsReusable { get { return false; } } /// <summary> /// 数字随机数 /// </summary> /// <returns></returns> private string GetRndNum() { string code = string.Empty; Random random = new Random(); for (int i = 0; i < 4; i++) { code += random.Next(9); } return code; } /// <summary> /// 英文随机 /// </summary> /// <returns></returns> private string GetRndStr() { string Vchar = "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 = Vchar.Split(','); string checkCode = string.Empty; Random rand = new Random(); for (int i = 0; i < 4; i++) { int t = rand.Next(VcArray.Length); checkCode += VcArray[t]; } return checkCode; } /// <summary> /// 中文随机 /// </summary> /// <returns></returns> private string GetRndCh() { System.Text.Encoding gb = System.Text.Encoding.Default;//获取GB2312编码页（表） object[] bytes = CreateRegionCode(4);//生4个随机中文汉字编码 string[] str = new string[4]; System.Text.StringBuilder sb = new System.Text.StringBuilder(); for (int i = 0; i < 4; i++) { //根据汉字编码的字节数组解码出中文汉字 str[i] = gb.GetString((byte[])Convert.ChangeType(bytes[i], typeof(byte[]))); sb.Append(str[i].ToString()); } return sb.ToString(); } /// <summary> /// 产生随机中文字符 /// </summary> /// <param name="strlength"></param> /// <returns></returns> private static object[] CreateRegionCode(int strlength) { //定义一个字符串数组储存汉字编码的组成元素 string[] rBase = new String[16] { "0", "1", "2", "3", "4", "5", "6", "7", "8", "9", "a", "b", "c", "d", "e", "f" }; Random rnd = new Random(); object[] bytes = new object[strlength]; for (int i = 0; i < strlength; i++) { //区位码第1位 int r1 = rnd.Next(11, 14); string str_r1 = rBase[r1].Trim(); //区位码第2位 rnd = new Random(r1 * unchecked((int)DateTime.Now.Ticks) + i); int r2; if (r1 == 13) { r2 = rnd.Next(0, 7); } else { r2 = rnd.Next(0, 16); } string str_r2 = rBase[r2].Trim(); //区位码第3位 rnd = new Random(r2 * unchecked((int)DateTime.Now.Ticks) + i);//更换随机种子 int r3 = rnd.Next(10, 16); string str_r3 = rBase[r3].Trim(); //区位码第4位 rnd = new Random(r3 * unchecked((int)DateTime.Now.Ticks) + i); int r4; if (r3 == 10) { r4 = rnd.Next(1, 16); } else if (r3 == 15) { r4 = rnd.Next(0, 15); } else { r4 = rnd.Next(0, 16); } string str_r4 = rBase[r4].Trim(); //定义两个字节变量存储产生的随机汉字区位码 byte byte1 = Convert.ToByte(str_r1 + str_r2, 16); byte byte2 = Convert.ToByte(str_r3 + str_r4, 16); //将两个字节变量存储在字节数组中 byte[] str_r = new byte[] { byte1, byte2 }; //将产生的一个汉字的字节数组放入object数组中 bytes.SetValue(str_r, i); } return bytes; } /// <summary> /// 画图片的背景图+干扰线 /// </summary> /// <param name="checkCode"></param> /// <returns></returns> private Bitmap CreateImages(string checkCode, string type) { int step = 0; if (type == "ch") { step = 5;//中文字符，边界值做大 } int iwidth = (int)(checkCode.Length * (13 + step)); System.Drawing.Bitmap image = new System.Drawing.Bitmap(iwidth, 22); Graphics g = Graphics.FromImage(image); g.Clear(Color.White);//清除背景色 Color[] c = { Color.Black, Color.Red, Color.DarkBlue, Color.Green, Color.Orange, Color.Brown, Color.DarkCyan, Color.Purple };//定义随机颜色 string[] font = { "Verdana", "Microsoft Sans Serif", "Comic Sans MS", "Arial", "宋体" }; Random rand = new Random(); for (int i = 0; i < 50; 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.LightGray, 1), x1, y1, x2, y2);//根据坐标画线 } for (int i = 0; i < checkCode.Length; i++) { int cindex = rand.Next(7); int findex = rand.Next(5); Font f = new System.Drawing.Font(font[findex], 10, 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 + step)), ii); } g.DrawRectangle(new Pen(Color.Black, 0), 0, 0, image.Width - 1, image.Height - 1); System.IO.MemoryStream ms = new System.IO.MemoryStream(); return image; }}
转载于:https://www.cnblogs.com/eric-gms/p/3465821.html
相关资源：ASP.NET动态验证码