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.Common12 {13     public class ValidationCodeHelper14     {15         /// 
16         /// 创建验证码17         /// 
18         /// 验证码位数19         /// 
     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         /// 
34         /// 产生图片35         /// 
36         /// 验证码37         public byte[] CreateImage(string code)38         {39             Bitmap image = new Bitmap(64, 32);40             Graphics g = Graphics.FromImage(image);41             try42             {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             finally85             {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:  换一张 js代码:

function changeOne() {

var image = document.getElementById('vCodeImage');

image.src = "@Url.Action("GetVCode","Account")/?t=" + (new Date()).getTime();

}