生成验证码

 1  public class ValidateCode
 2     {
 3         /// <summary>
 4         /// 生成验证码
 5         /// </summary>
 6         /// <param name="length">指定验证码的长度</param>
 7         /// <returns></returns>
 8         public string CreateValidateCode(int length)
 9         {
10             int[] randMembers = new int[length];
11             int[] validateNums = new int[length];
12             string validateNumberStr = "";
13             //生成起始序列值
14             int seekSeek = unchecked((int)DateTime.Now.Ticks);
15             Random seekRand = new Random(seekSeek);
16             int beginSeek = (int)seekRand.Next(0, Int32.MaxValue - length * 10000);
17             int[] seeks = new int[length];
18             for (int i = 0; i < length; i++)
19             {
20                 beginSeek += 10000;
21                 seeks[i] = beginSeek;
22             }
23             //生成随机数字
24             for (int i = 0; i < length; i++)
25             {
26                 Random rand = new Random(seeks[i]);
27                 int pownum = 1 * (int)Math.Pow(10, length);
28                 randMembers[i] = rand.Next(pownum, Int32.MaxValue);
29             }
30             //抽取随机数字
31             for (int i = 0; i < length; i++)
32             {
33                 string numStr = randMembers[i].ToString();
34                 int numLength = numStr.Length;
35                 Random rand = new Random();
36                 int numPosition = rand.Next(0, numLength - 1);
37                 validateNums[i] = Int32.Parse(numStr.Substring(numPosition, 1));
38             }
39             //生成验证码
40             for (int i = 0; i < length; i++)
41             {
42                 validateNumberStr += validateNums[i].ToString();
43             }
44             return validateNumberStr;
45         }
46         /// <summary>
47         /// 创建验证码的图片
48         /// </summary>
49         /// <param name="containsPage">要输出到的page对象</param>
50         /// <param name="validateNum">验证码</param>
51         public byte[] CreateValidateGraphic(string validateCode)
52         {
53             Bitmap image = new Bitmap((int)Math.Ceiling(validateCode.Length * 12.0), 22);
54             Graphics g = Graphics.FromImage(image);
55             try
56             {
57                 //生成随机生成器
58                 Random random = new Random();
59                 //清空图片背景色
60                 g.Clear(Color.White);
61                 //画图片的干扰线
62                 for (int i = 0; i < 25; i++)
63                 {
64                     int x1 = random.Next(image.Width);
65                     int x2 = random.Next(image.Width);
66                     int y1 = random.Next(image.Height);
67                     int y2 = random.Next(image.Height);
68                     g.DrawLine(new Pen(Color.Silver), x1, y1, x2, y2);
69                 }
70                 Font font = new Font("Arial", 12, (FontStyle.Bold | FontStyle.Italic));
71                 LinearGradientBrush brush = new LinearGradientBrush(new Rectangle(0, 0, image.Width, image.Height),
72                  Color.Blue, Color.DarkRed, 1.2f, true);
73                 g.DrawString(validateCode, font, brush, 3, 2);
74                 //画图片的前景干扰点
75                 for (int i = 0; i < 100; i++)
76                 {
77                     int x = random.Next(image.Width);
78                     int y = random.Next(image.Height);
79                     image.SetPixel(x, y, Color.FromArgb(random.Next()));
80                 }
81                 //画图片的边框线
82                 g.DrawRectangle(new Pen(Color.Silver), 0, 0, image.Width - 1, image.Height - 1);
83                 //保存图片数据
84                 MemoryStream stream = new MemoryStream();
85                 image.Save(stream, ImageFormat.Jpeg);
86                 //输出图片流
87                 return stream.ToArray();
88             }
89             finally
90             {
91                 g.Dispose();
92                 image.Dispose();
93             }
94         }
95     }