.NET MVC 验证码

.NET MVC 验证码

验证码示例图片

效果差不多就这样，接下来直接上代码。

验证码生成器

1. public class ValidateCode
2. {
3. public static ValidateCode Default = new ValidateCode();
4. public int ImageWidth { get; set; }
5. public int ImageHeight { get; set; }
6. public string Letters { get; set; }
7. public int CodeLength { get; set; }
8. private Random r = new Random();
9. public ValidateCode()
10. {
11. ImageWidth = 200;
12. ImageHeight = 60;
13. CodeLength = 6;
14. Letters = "abcdefghijkmnpqrstuvwxyzABCDEFGHJKLMNPQRSTUVWXYZ1234567890";
15. }
16. public string GetValidationCode()
17. {
18. //合法随机显示字符列表
19. System.Text.StringBuilder s = new System.Text.StringBuilder();
20. //将随机生成的字符串绘制到图片上
21. for (int i = 0; i < CodeLength; i++)
22. {
23. s.Append(Letters.Substring(r.Next(0, Letters.Length - 1), 1));
24. }
25. return s.ToString();
26. }
27. public byte[] GetValidationImage(string codeString)
28. {
29. //设置输出流图片格式
30. var b = new System.Drawing.Bitmap(ImageWidth, ImageHeight);
31. var g = System.Drawing.Graphics.FromImage(b);
32. int ColorR = r.Next(0, 255);
33. int ColorG = r.Next(0, 255);
34. int ColorB = r.Next(0, 255);
36. g.FillRectangle(new System.Drawing.SolidBrush(System.Drawing.Color.FromArgb(ColorR, ColorG, ColorB)), 0, 0, 200, 60);
37. var font = new System.Drawing.Font(System.Drawing.FontFamily.GenericSerif, 48, System.Drawing.FontStyle.Bold, System.Drawing.GraphicsUnit.Pixel);
39. //合法随机显示字符列表
41. //将随机生成的字符串绘制到图片上
42. for (int i = 0; i < codeString.Length; i++)
43. {
44. int sR = r.Next(0, 255);
45. int sG = r.Next(0, 255);
46. int sB = r.Next(0, 255);
47. while (Math.Abs(sR - ColorR) < 35) sR = r.Next(0, 255);
48. while (Math.Abs(sG - ColorG) < 35) sG = r.Next(0, 255);
49. while (Math.Abs(sB - ColorB) < 35) sB = r.Next(0, 255);
50. g.DrawString(codeString[i].ToString(), font, new System.Drawing.SolidBrush(System.Drawing.Color.FromArgb(sR, sG, sB)), i * (200 / codeString.Length - 2), r.Next(0, 15));
51. }
53. //生成干扰线条
54. var pen = new System.Drawing.Pen(new System.Drawing.SolidBrush(System.Drawing.Color.FromArgb(r.Next(0, 255), r.Next(0, 255), r.Next(0, 255))), 2);
55. for (int i = 0; i < 10; i++)
56. {
57. g.DrawLine(pen, new System.Drawing.Point(r.Next(0, 199), r.Next(0, 59)), new System.Drawing.Point(r.Next(0, 199), r.Next(0, 59)));
58. }
60. var stream = new System.IO.MemoryStream();
61. b.Save(stream, System.Drawing.Imaging.ImageFormat.Jpeg);
62. g.Dispose();
63. b.Dispose();
64. //输出图片流
65. return stream.ToArray();
66. }
67. }

使用方法

1. public ActionResult validateCode() //创建一个action用于返回验证码图片
2. {
3. string validateCode = ValidateCode.Default.GetValidationCode(); //获取验证码
4. Session["LoginValidateCode"] = validateCode; //将验证码保存到Session中
5. return File(ValidateCode.Default.GetValidationImage(validateCode), @"image/jpeg"); //返回验证码图片
6. }
7. //直接将这个action 的地址赋值给img标签就可以了，例如 <img src="http://localhost:5695/home/validateCode" alt="">
9. public ActionResult Login(string validateCode)
10. {
11. if (String.IsNullOrEmpty(Session["LoginValidateCode"].ToString()))
12. {
13. return Content("你登录页面停留的时间过久页已经超时");
14. }
15. else if (!Session["LoginValidateCode"].ToString().Equals(validateCode, StringComparison.CurrentCultureIgnoreCase))
16. {
17. return Content("验证码错误");
18. }
20. return RedirectToAction("Index"); //成功
21. }