一个简单的ASP.NET验证码
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2022-06-21 08:38:41
本文实例为大家分享了asp.net验证码的具体代码,供大家参考,具体内容如下
我主要是看到干扰线了,一个验证码里面要是没有干扰线什么的,至少得在噪点和随机码的排版上下工夫...
本文实例为大家分享了asp.net验证码的具体代码,供大家参考,具体内容如下
我主要是看到干扰线了,一个验证码里面要是没有干扰线什么的,至少得在噪点和随机码的排版上下工夫:
/// <summary> /// 验证码生成类 /// </summary> public class verify_code : ihttphandler, irequiressessionstate { public void processrequest(httpcontext context) { int codew = 80; int codeh = 22; int fontsize = 16; string chkcode = string.empty; //颜色列表,用于验证码、噪线、噪点 color[] color = { color.black, color.red, color.blue, color.green, color.orange, color.brown, color.brown, color.darkblue }; //字体列表,用于验证码 string[] font = { "times new roman", "verdana", "arial", "gungsuh", "impact" }; //验证码的字符集,去掉了一些容易混淆的字符 char[] character = { '0', '1', '2', '3', '4', '5', '6', '8', '9' }; random rnd = new random(); //生成验证码字符串 for (int i = 0; i < 4; i++) { chkcode += character[rnd.next(character.length)]; } //写入session context.session["sys_verify_code"] = chkcode; //创建画布 bitmap bmp = new bitmap(codew, codeh); graphics g = graphics.fromimage(bmp); g.clear(color.white); //画噪线 for (int i = 0; i < 4; i++) { int x1 = rnd.next(codew); int y1 = rnd.next(codeh); int x2 = rnd.next(codew); int y2 = rnd.next(codeh); color clr = color[rnd.next(color.length)]; g.drawline(new pen(clr), x1, y1, x2, y2); } //画验证码字符串 for (int i = 0; i < chkcode.length; i++) { string fnt = font[rnd.next(font.length)]; font ft = new font(fnt, fontsize); color clr = color[rnd.next(color.length)]; g.drawstring(chkcode[i].tostring(), ft, new solidbrush(clr), (float)i * 18 + 2, (float)0); } //画噪点 for (int i = 0; i < 100; i++) { int x = rnd.next(bmp.width); int y = rnd.next(bmp.height); color clr = color[rnd.next(color.length)]; bmp.setpixel(x, y, clr); } //清除该页输出缓存,设置该页无缓存 context.response.buffer = true; context.response.expiresabsolute = system.datetime.now.addmilliseconds(0); context.response.expires = 0; context.response.cachecontrol = "no-cache"; context.response.appendheader("pragma", "no-cache"); //将验证码图片写入内存流,并将其以 "image/png" 格式输出 memorystream ms = new memorystream(); try { bmp.save(ms, imageformat.png); context.response.clearcontent(); context.response.contenttype = "image/png"; context.response.binarywrite(ms.toarray()); } finally { //显式释放资源 bmp.dispose(); g.dispose(); } } public bool isreusable { get { return false; } } }
基本验证生成代码demo:
using system; using system.drawing; using system.drawing.imaging; using system.io; using system.web; public partial class image : system.web.ui.page { protected void page_load(object sender, eventargs e) { string tmp = rndnum(4); httpcookie a = new httpcookie("imagev", tmp); response.cookies.add(a); this.validatecode(tmp); } private void validatecode(string vnum) { bitmap img = null; graphics g = null; memorystream ms = null; int gheight = vnum.length * 12; img = new bitmap(gheight, 25); g = graphics.fromimage(img); //背景颜色 g.clear(color.white); //文字字体 font f = new font("arial black", 10); //文字颜色 solidbrush s = new solidbrush(color.black); g.drawstring(vnum, f, s, 3, 3); ms = new memorystream(); img.save(ms, imageformat.jpeg); response.clearcontent(); response.contenttype = "image/jpeg"; response.binarywrite(ms.toarray()); g.dispose(); img.dispose(); response.end(); } private string rndnum(int vcodenum) { string vchar = "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"; string[] vcarray = vchar.split(new char[] { ',' }); string vnum = ""; int temp = -1; random rand = new random(); for (int i = 1; i < vcodenum + 1; i++) { if (temp != -1) { rand = new random(i * temp * unchecked((int)datetime.now.ticks)); } int t = rand.next(35); if (temp != -1 && temp == t) { return rndnum(vcodenum); } temp = t; vnum += vcarray[t]; } return vnum; } }
以上就是本文的全部内容,希望对大家的学习有所帮助,也希望大家多多支持。