验证码生成 c#

1.验证码生成类

 1 using System;
 2 using System.Collections.Generic;
 3 using System.Drawing;
 4 using System.Drawing.Drawing2D;
 5 using System.Drawing.Imaging;
 6 using System.IO;
 7 using System.Linq;
 8 using System.Web;
 9 using System.Web.UI.WebControls;
10 
11 namespace AuthenticationDemo.Common
12 {
13     public class ValidationCodeHelper
14     {
15         /// <summary>
16         /// 创建验证码
17         /// </summary>
18         /// <param name="codeLength">验证码位数</param>
19         /// <returns></returns>
20         public string CreateCode(int codeLength)
21         {
22             // 不要   "0"
23             string so = "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";
24             string[] strArr = so.Split(',');
25             string code = "";
26             Random rand = new Random();
27             for (int i = 0; i < codeLength; i++)
28             {
29                 code += strArr[rand.Next(0, strArr.Length)];
30             }
31             return code;
32         }
33         /// <summary>
34         /// 产生图片
35         /// </summary>
36         /// <param name="code">验证码</param>
37         public byte[] CreateImage(string code)
38         {
39             Bitmap image = new Bitmap(64, 32);
40             Graphics g = Graphics.FromImage(image);
41             try
42             {
43                 //随机转动角度 
44                 //int randAngle = 45;
45                 //实例随机生成器
46                 Random random = new Random();
47                 //清空图片背景色
48                 g.Clear(Color.White);
49                 //画图片的干扰线
50                 for (int i = 0; i < 25; i++)
51                 {
52                     int x1 = random.Next(image.Width);
53                     int x2 = random.Next(image.Width);
54                     int y1 = random.Next(image.Height);
55                     int y2 = random.Next(image.Height);
56                     g.DrawLine(new Pen(Color.Silver), x1, y1, x2, y2);
57                 }
58                 Font font = new Font("Arial", 16, (FontStyle.Bold | FontStyle.Italic));
59                 LinearGradientBrush brush = new LinearGradientBrush(new Rectangle(0, 0, image.Width, image.Height),
60                  Color.Blue, Color.DarkRed, 1.2f, true);
61                 //float angle = random.Next(-randAngle,randAngle);
62                 //g.RotateTransform(angle);
63                 g.DrawString(code, font, brush, 3, 2);
64                 //g.RotateTransform(angle);
65                 //画图片的前景干扰点
66                 for (int i = 0; i < 100; i++)
67                 {
68                     int x = random.Next(image.Width);
69                     int y = random.Next(image.Height);
70                     image.SetPixel(x, y, Color.FromArgb(random.Next()));
71                 }
72                 //画图片的边框线
73                 g.DrawRectangle(new Pen(Color.Silver), 0, 0, image.Width - 1, image.Height - 1);
74                 //保存图片数据
75                 MemoryStream ms = new MemoryStream();
76                 image.Save(ms, ImageFormat.Jpeg);
77                 //输出图片流
78                 return ms.ToArray();
79             }
80             catch (Exception)
81             {
82                 throw;
83             }
84             finally
85             {
86                 g.Dispose();
87                 image.Dispose();
88             }
89         }
90 
91     }
92 }

2.后台调用

   public ActionResult GetVCode()
        {
            ValidationCodeHelper vc = new ValidationCodeHelper();
            //验证码
            string code = vc.CreateCode(4);
            Session["vCode"] = code;//保存生成的验证码,提供之后与用户的输入的验证码比较
            byte[] bytes = vc.CreateImage(code);
            return File(bytes, @"image/jpeg");
        }

3.html页面

html代码: 
<img id="vCodeImage" src="@Url.Action("GetVCode","Account")?t=@DateTime.Now.Ticks" alt="验证码图片" title="验证码图片" style="display:inline" />
 <a href="#" onclick="changeOne()">换一张</a>
js代码:

function changeOne() {
var image = document.getElementById('vCodeImage');
image.src = "@Url.Action("GetVCode","Account")/?t=" + (new Date()).getTime();
}