C# 比较不错的通用验证码

1 using System;
 using System.Collections.Generic;
 using System.Drawing;
 using System.Drawing.Imaging;
 using System.IO;
 using System.Linq;
 using System.Web;

 namespace CasCall
 {
     public class service_code : System.Web.UI.Page
     {
         #region
         public string RandCode()
         {
             int CodeCount = ;//生成4个随机数
             string randomChar = "2,3,4,5,6,7,8,9,A,B,C,D,E,F,G,H,J,K,L,M,N,P,Q,R,S,T,U,V,W,X,Y,Z";
             randomChar = randomChar.Replace(",", "");
             string RandomCode = "";
             System.Threading.Thread.Sleep();
             char[] allCharArray = randomChar.ToCharArray();
             int n = allCharArray.Length;
             System.Random random = new Random(~unchecked((int)DateTime.Now.Ticks));
             for (int i = ; i < CodeCount; i++)
             {
                 int rnd = random.Next(, n);
                 RandomCode += allCharArray[rnd];
             }
             return RandomCode;
         }
         #endregion
         #region 验证码
         ///  <summary>
         ///  创建验证码图片
         ///  </summary>
         ///  <param  name="randomcode">验证码</param>
         public byte[] CreateImage(string randomcode)
         {
             int randAngle = ; //随机转动角度
             int mapwidth = (int)(randomcode.Length * );
             Bitmap map = new Bitmap(mapwidth, );//创建图片背景
             Graphics graph = Graphics.FromImage(map);
             graph.Clear(Color.White);//清除画面，填充背景
             //graph.DrawRectangle(new Pen(Color.Silver, 0), 0, 0, map.Width - 1, map.Height - 1);//画一个边框  

             Random rand = new Random();

             //验证码旋转，防止机器识别
             char[] chars = randomcode.ToCharArray();//拆散字符串成单字符数组
             //文字距中
             StringFormat format = new StringFormat(StringFormatFlags.NoClip);
             format.Alignment = StringAlignment.Center;
             format.LineAlignment = StringAlignment.Center;
             //定义颜色
             Color[] c = { Color.Black, Color.Red, Color.Blue, Color.Green,
                             Color.Orange, Color.Brown, Color.DarkBlue };

             //画图片的背景噪音线
             for (int i = ; i < ; i++)
             {
                 int x1 = rand.Next();
                 int x2 = rand.Next(map.Width - , map.Width);
                 int y1 = rand.Next(map.Height);
                 int y2 = rand.Next(map.Height);

                 graph.DrawLine(new Pen(c[rand.Next()]), x1, y1, x2, y2);
             }

             for (int i = ; i < chars.Length; i++)
             {
                 int cindex = rand.Next();
                 int findex = rand.Next();
                 Font f = new System.Drawing.Font("Arial", , System.Drawing.FontStyle.Regular);//字体样式(参数2为字体大小)
                 Brush b = new System.Drawing.SolidBrush(c[cindex]);
                 Point dot = new Point(, );
                 float angle = rand.Next(-randAngle, randAngle);//转动的度数
                 graph.TranslateTransform(dot.X, dot.Y);//移动光标到指定位置
                 graph.RotateTransform(angle);
                 graph.DrawString(chars[i].ToString(), f, b, , , format);
                 graph.RotateTransform(-angle);//转回去
                 graph.TranslateTransform(, -dot.Y);//移动光标到指定位置
             }
             //生成图片
             System.IO.MemoryStream ms = new System.IO.MemoryStream();
             MemoryStream stream = new MemoryStream();
             map.Save(stream, ImageFormat.Jpeg);
             graph.Dispose();
             map.Dispose();
             return stream.ToArray();

         }
         #endregion
     }
 }

前台

  <label class="panel-body">验证码：</label>
  <input type="text" id="yzm" name="yzm" class="form-control" />&nbsp;&nbsp;</td>
  <img id="ValidCode" style="cursor: pointer;" src="/SignIn/YanZhengMa" alt="验证码"  onclick="this.src='/SignIn/YanZhengMa?time=' + new Date().getTime();" />
  <a href="#" id="Changes" data-toggle="modal" data-target="#mymodel">看不清,换一张</a>

JS

$("#Changes").click(function () {
        document.getElementById("ValidCode").src = '/SignIn/YanZhengMa?time=' + new Date().getTime();
    });

　　后台调用

  /// <summary>
         /// 生成验证码
         /// </summary>
         /// <returns></returns>
         public ActionResult YanZhengMa()
         {
             service_code sc = new service_code();
             string vVerificationCode = sc.RandCode();
             Session["vcode"] = vVerificationCode.ToLower();
            // Safe.SessionAdd("vcode", vVerificationCode.ToLower(), 2);   //Session中保存验证码
             sc.CreateImage(vVerificationCode);
             return File(sc.CreateImage(vVerificationCode), @"image/jpeg");
         }

 效果图