一个好的验证码生成类

using System;


using System.Drawing;


using System.Drawing.Imaging;


using System.Web.UI;


using System.Drawing.Drawing2D;


using System.IO;


namespace Bll




...{




/**//// <summary>


/// 生成验证码的类


/// </summary>


public class ValidateNumber




...{


public ValidateNumber()




...{


}




/**//// <summary>


/// 验证码的最大长度


/// </summary>


public int MaxLength




...{




get ...{ return 10; }


}




/**//// <summary>


/// 验证码的最小长度


/// </summary>


public int MinLength




...{




get ...{ return 1; }


}




/**//// <summary>


/// 生成验证码


/// </summary>


/// <param name="length">指定验证码的长度</param>


/// <returns></returns>


public string CreateValidateNumber(int length)




...{


int[] randMembers = new int[length];


int[] validateNums = new int[length];


string validateNumberStr = "";


//生成起始序列值


int seekSeek = unchecked((int)DateTime.Now.Ticks);


Random seekRand = new Random(seekSeek);


int beginSeek = (int)seekRand.Next(0, Int32.MaxValue - length * 10000);


int[] seeks = new int[length];


for (int i = 0; i < length; i++)




...{


beginSeek += 10000;


seeks[i] = beginSeek;


}


//生成随机数字


for (int i = 0; i < length; i++)




...{


Random rand = new Random(seeks[i]);


int pownum = 1 * (int)Math.Pow(10, length);


randMembers[i] = rand.Next(pownum, Int32.MaxValue);


}


//抽取随机数字


for (int i = 0; i < length; i++)




...{


string numStr = randMembers[i].ToString();


int numLength = numStr.Length;


Random rand = new Random();


int numPosition = rand.Next(0, numLength - 1);


validateNums[i] = Int32.Parse(numStr.Substring(numPosition, 1));


}


//生成验证码


for (int i = 0; i < length; i++)




...{


validateNumberStr += validateNums[i].ToString();


}


return validateNumberStr;


}




/**//// <summary>


/// 创建验证码的图片


/// </summary>


/// <param name="containsPage">要输出到的page对象</param>


/// <param name="validateNum">验证码</param>


public void CreateValidateGraphic(Page containsPage, string validateNum)




...{


Bitmap image = new Bitmap((int)Math.Ceiling(validateNum.Length * 12.5), 22);


Graphics g = Graphics.FromImage(image);


try




...{


//生成随机生成器


Random random = new Random();


//清空图片背景色


g.Clear(Color.White);


//画图片的干扰线


for (int i = 0; i < 25; i++)




...{


int x1 = random.Next(image.Width);


int x2 = random.Next(image.Width);


int y1 = random.Next(image.Height);


int y2 = random.Next(image.Height);


g.DrawLine(new Pen(Color.Silver), x1, y1, x2, y2);


}


Font font = new Font("Arial", 12, (FontStyle.Bold | FontStyle.Italic));


LinearGradientBrush brush = new LinearGradientBrush(new Rectangle(0, 0, image.Width, image.Height),


Color.Blue, Color.DarkRed, 1.2f, true);


g.DrawString(validateNum, font, brush, 3, 2);


//画图片的前景干扰点


for (int i = 0; i < 100; i++)




...{


int x = random.Next(image.Width);


int y = random.Next(image.Height);


image.SetPixel(x, y, Color.FromArgb(random.Next()));


}


//画图片的边框线


g.DrawRectangle(new Pen(Color.Silver), 0, 0, image.Width - 1, image.Height - 1);


//保存图片数据


MemoryStream stream = new MemoryStream();


image.Save(stream, ImageFormat.Jpeg);


//输出图片


containsPage.Response.Clear();


containsPage.Response.ContentType = "image/jpeg";


containsPage.Response.BinaryWrite(stream.ToArray());


}


finally




...{


g.Dispose();


image.Dispose();


}


}




/**//// <summary>


/// 得到验证码图片的长度


/// </summary>


/// <param name="validateNumLength">验证码的长度</param>


/// <returns></returns>


public static int GetImageWidth(int validateNumLength)




...{


return (int)(validateNumLength * 12.5);


}




/**//// <summary>


/// 得到验证码的高度


/// </summary>


/// <returns></returns>


public static double GetImageHeight()




...{


return 22.5;


}


}


}