1 /// <summary>  2     /// 验证码类  3     /// </summary>  4     public class ValidateCode  5     {  6         /// <summary>  7         /// 验证码的最大长度  8         /// </summary>  9         public int MaxLength { get { return 10; } } 10  11         /// <summary> 12         /// 验证码的最小长度 13         /// </summary> 14         public int MinLength { get { return 1; } } 15  16         /// <summary> 17         /// 生成指定长度的验证码字符串 18         /// </summary> 19         /// <param name="length"></param> 20         /// <returns></returns> 21         public string CreateValidateCodeStr(int length) 22         {  23             //生成起始序列值 24             int seed = unchecked((int)DateTime.Now.Ticks); 25             Random seedRandom = new Random(seed); 26             int beginSeed = seedRandom.Next(0, Int32.MaxValue - length * 10000); 27             int[] seeds=new int[length]; 28             for (int i = 0; i < length; i++) 29             { 30                 beginSeed += 10000; 31                 seeds[i] = beginSeed; 32             } 33  34             //生成随机数 35             int[] randMembers = new int[length]; 36             for (int i = 0; i < length; i++) 37             { 38                 Random rand = new Random(seeds[i]); 39                 int p = 1 * (int)Math.Pow(10, length); 40                 randMembers[i] = rand.Next(p, Int32.MaxValue); 41             } 42  43             //抽取随机数字 44             int[] validateNums=new int[length]; 45             for (int i = 0; i < length; i++) 46             { 47                 string numStr = randMembers[i].ToString(); 48                 int numLength = numStr.Length; 49                 Random rand = new Random(); 50                 int numPosition = rand.Next(0, numLength - 1); 51                 validateNums[i] = Int32.Parse(numStr.Substring(numPosition, 1)); 52             } 53  54             //生成验证码 55             string validateCodeStr = ""; 56             for (int i = 0; i < length; i++) 57             { 58                 validateCodeStr += validateNums[i].ToString(); 59             } 60  61             return validateCodeStr; 62         } 63  64         /// <summary> 65         /// 创建验证码的图片 66         /// </summary> 67         /// <param name="validateCodeStr"></param> 68         /// <returns></returns> 69         public byte[] CreateValidateImg(string validateCodeStr) 70         { 71             Bitmap bitmap = new Bitmap((int)Math.Ceiling(validateCodeStr.Length * 12.0), 22); 72             Graphics g = Graphics.FromImage(bitmap); 73             try 74             { 75                 //清空图片的背景色 76                 g.Clear(Color.White); 77                 //实例化随机生成器 78                 Random rand = new Random(); 79                 //画图片的干扰线 80                 for (int i = 0; i < 25; i++) 81                 { 82                     int x1 = rand.Next(bitmap.Width); 83                     int y1 = rand.Next(bitmap.Height); 84                     int x2 = rand.Next(bitmap.Width); 85                     int y2 = rand.Next(bitmap.Height); 86                     g.DrawLine(new Pen(Color.Silver), x1, y1, x2, y2); 87                 } 88                 //画字符串 89                 Font font = new Font("Arial", 12, (FontStyle.Bold | FontStyle.Italic)); 90                 LinearGradientBrush brush = new LinearGradientBrush(new Rectangle(0, 0, bitmap.Width, bitmap.Height), Color.Blue, Color.DarkRed, 1.2f, true); 91                 g.DrawString(validateCodeStr, font, brush, 3, 2); 92                 //画图片的前景干扰点 93                 for (int i = 0; i < 100; i++) 94                 { 95                     int x = rand.Next(bitmap.Width); 96                     int y = rand.Next(bitmap.Height); 97                     bitmap.SetPixel(x, y, Color.FromArgb(rand.Next())); 98                 } 99                 //画图片的边框线100                 g.DrawRectangle(new Pen(Color.Silver), 0, 0, bitmap.Width - 1, bitmap.Height - 1);101                 //保存图片数据102                 MemoryStream stream = new MemoryStream();103                 bitmap.Save(stream, ImageFormat.Jpeg);104                 //输出图片流105                 return stream.ToArray();106             }107             finally 108             {109                 g.Dispose();110                 bitmap.Dispose();111             }112         }113 114         /// <summary>115         /// 得到验证码图片的长度116         /// </summary>117         /// <param name="validateNumLength">验证码的长度</param>118         /// <returns></returns>119         public static int GetImgWidth(int validateNumLength)120         {121             return (int)(validateNumLength * 12.0);122         }123 124         /// <summary>125         /// 得到验证码图片的高度126         /// </summary>127         /// <returns></returns>128         public static double GetImgHeight()129         {130             return 22.5;131         }132     }