ASP.NET验证码制作

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;   }    }

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