asp.net验证码生成类(参考)

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using System;
using System.Drawing;
using System.Drawing.Imaging;
using System.Web.UI;
using System.Drawing.Drawing2D;
using System.IO;
namespace Validate
{
/// <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;
}
}
}