html部分：
1 <!DOCTYPE html> 2 <html lang="en"> 3 <head> 4 <meta charset="UTF-8"> 5 <title>Document</title> 6 </head> 7 <body> 8 <table> 9 <tr> 10 <td><img id="validImg" src="/Login/CheckCode?ID=1" alt="点我刷新" onclick="changeValidCode()"></td> 11 <td><a href="#" onclick="changeValidCode()">点我刷新</a></td> 12 </tr> 13 </table> 14 15 16 <script > 17 $(function(){ 18 function changeValidCode(){ 19 var code=$("#validImg").attr('src'); 20 $("#validImg").attr("src", code + "1"); 21 } 22 }) 23 </script> 24 </body> 25 </html>
asp.net mvc返回文件地址：
1 using System; 2 using System.Collections.Generic; 3 using System.Linq; 4 using System.Web; 5 using System.Web.Mvc; 6 7 namespace MyDemo.Controllers 8 { 9 public class LoginController : Controller 10 { 11 12 13 14 /// <summary> 15 /// 用户登录验证码 16 /// </summary> 17 /// <returns></returns> 18 public ActionResult CheckCode() 19 { 20 21 ValidateCode vCode = new ValidateCode(); 22 string code = vCode.CreateValidateCode(5); 23 Session["SysValidateCode"] = code; 24 byte[] bytes = vCode.CreateValidateGraphic(code); 25 return File(bytes, @"image/jpeg"); 26 } 27 28 } 29 }
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.Text; 9 10 namespace MyDemo.Model 11 { 12 /// <summary> 13 /// 生成验证码的类 14 /// </summary> 15 public class ValidateCode 16 { 17 public ValidateCode() 18 { 19 } 20 /// <summary> 21 /// 验证码的最大长度 22 /// </summary> 23 public int MaxLength 24 { 25 get { return 10; } 26 } 27 /// <summary> 28 /// 验证码的最小长度 29 /// </summary> 30 public int MinLength 31 { 32 get { return 1; } 33 } 34 /// <summary> 35 /// 生成验证码 36 /// </summary> 37 /// <param name="length">指定验证码的长度</param> 38 /// <returns></returns> 39 public string CreateValidateCode(int length) 40 { 41 int[] randMembers = new int[length]; 42 int[] validateNums = new int[length]; 43 string validateNumberStr = ""; 44 //生成起始序列值 45 int seekSeek = unchecked((int)DateTime.Now.Ticks); 46 Random seekRand = new Random(seekSeek); 47 int beginSeek = (int)seekRand.Next(0, Int32.MaxValue - length * 10000); 48 int[] seeks = new int[length]; 49 for (int i = 0; i < length; i++) 50 { 51 beginSeek += 10000; 52 seeks[i] = beginSeek; 53 } 54 //生成随机数字 55 for (int i = 0; i < length; i++) 56 { 57 Random rand = new Random(seeks[i]); 58 int pownum = 1 * (int)Math.Pow(10, length); 59 randMembers[i] = rand.Next(pownum, Int32.MaxValue); 60 } 61 //抽取随机数字 62 for (int i = 0; i < length; i++) 63 { 64 string numStr = randMembers[i].ToString(); 65 int numLength = numStr.Length; 66 Random rand = new Random(); 67 int numPosition = rand.Next(0, numLength - 1); 68 validateNums[i] = Int32.Parse(numStr.Substring(numPosition, 1)); 69 } 70 //生成验证码 71 for (int i = 0; i < length; i++) 72 { 73 validateNumberStr += validateNums[i].ToString(); 74 } 75 return validateNumberStr; 76 } 77 78 /// <summary> 79 /// 创建验证码的图片 80 /// </summary> 81 /// <param name="containsPage">要输出到的page对象</param> 82 /// <param name="validateNum">验证码</param> 83 public byte[] CreateValidateGraphic(string validateCode) 84 { 85 Bitmap image = new Bitmap((int)Math.Ceiling(validateCode.Length * 16.0), 40); 86 Graphics g = Graphics.FromImage(image); 87 try 88 { 89 //生成随机生成器 90 Random random = new Random(); 91 //清空图片背景色 92 g.Clear(Color.White); 93 //画图片的干扰线 94 for (int i = 0; i < 25; i++) 95 { 96 int x1 = random.Next(image.Width); 97 int x2 = random.Next(image.Width); 98 int y1 = random.Next(image.Height); 99 int y2 = random.Next(image.Height); 100 g.DrawLine(new Pen(Color.Silver), x1, y1, x2, y2); 101 } 102 Font font = new Font("Arial", 16, (FontStyle.Bold | FontStyle.Italic)); 103 LinearGradientBrush brush = new LinearGradientBrush(new Rectangle(0, 0, image.Width, image.Height), 104 Color.Blue, Color.DarkRed, 1.2f, true); 105 g.DrawString(validateCode, font, brush, 3, 2); 106 //画图片的前景干扰点 107 for (int i = 0; i < 100; i++) 108 { 109 int x = random.Next(image.Width); 110 int y = random.Next(image.Height); 111 image.SetPixel(x, y, Color.FromArgb(random.Next())); 112 } 113 //画图片的边框线 114 g.DrawRectangle(new Pen(Color.Silver), 0, 0, image.Width - 1, image.Height - 1); 115 //保存图片数据 116 MemoryStream stream = new MemoryStream(); 117 image.Save(stream, ImageFormat.Jpeg); 118 //输出图片流 119 return stream.ToArray(); 120 } 121 finally 122 { 123 g.Dispose(); 124 image.Dispose(); 125 } 126 } 127 /// <summary> 128 /// 得到验证码图片的长度 129 /// </summary> 130 /// <param name="validateNumLength">验证码的长度</param> 131 /// <returns></returns> 132 public static int GetImageWidth(int validateNumLength) 133 { 134 return (int)(validateNumLength * 16.0); 135 } 136 /// <summary> 137 /// 得到验证码的高度 138 /// </summary> 139 /// <returns></returns> 140 public static double GetImageHeight() 141 { 142 return 40; 143 } 144 } 145 }