(200分)讨论各大论坛的验证码算法(在线等)

Question

过几天再补加100分，
请熟悉验证码算法的朋友帮忙介绍下，
谢谢

Answer 1

我的。随机使用不同的字体，并且随机transform,还有加了噪点
using System;
using System.Collections;
using System.ComponentModel;
using System.Data;
using System.Drawing;
using System.Drawing.Drawing2D;
using System.Drawing.Imaging;
using System.Web;
using System.Web.SessionState;
using System.Web.UI;
using System.Web.UI.WebControls;
using System.Web.UI.HtmlControls;using System.IO;namespace Shop
{
/// <summary>
/// Summary description for ValidateCode.
/// </summary>
public class ValidateCode : System.Web.UI.Page
{
/// <summary>
/// Validation Code generated fromt these charaters.
/// Note: l,L 1(number), o, O, 0(number) are removed
/// </summary>
private const string strValidateCodeBound = "abcdefghijkmnpqrstuvwxyzABCDEFGHIJKLMNPQRSTUVWXYZ23456789";
private static string[] Fonts = new string[] {  "Helvetica",
 "Geneva", 
 "sans-serif",
 "Verdana",
 "Times New Roman",
 "Courier New",
 "Arial"
 };
#region Web Form Designer generated code
override protected void OnInit(EventArgs e)
{
//
// CODEGEN: This call is required by the ASP.NET Web Form Designer.
//
InitializeComponent();
base.OnInit(e);
}

/// <summary>
/// Required method for Designer support - do not modify
/// the contents of this method with the code editor.
/// </summary>
private void InitializeComponent()
{    
this.Load += new System.EventHandler(this.Page_Load); }
#endregion /// <summary>
/// event handler of page load
/// </summary>
private void Page_Load(object sender, System.EventArgs e)
{
if(!IsPostBack)
{
string str_ValidateCode = GetRandomString(6); Session["ValidateCode"] = str_ValidateCode;
CreateImage(str_ValidateCode);
} } /// <summary>
/// Generate random string
/// </summary>
private string GetRandomString(int int_NumberLength)
{
string valString = string.Empty;
Random theRandomNumber = new Random((int)DateTime.Now.Ticks); for (int int_index = 0; int_index < int_NumberLength; int_index++)
valString += strValidateCodeBound[theRandomNumber.Next(strValidateCodeBound.Length - 1)].ToString(); return valString;
} /// <summary>
/// Generate random Color
/// </summary>
private Color GetRandomColor()
{
Random RandomNum_First = new Random((int)DateTime.Now.Ticks);

System.Threading.Thread.Sleep(RandomNum_First.Next(50));
Random RandomNum_Sencond = new Random((int)DateTime.Now.Ticks);       
int int_Red = RandomNum_First.Next(256);
int int_Green = RandomNum_Sencond.Next(256);
int int_Blue = (int_Red + int_Green > 400) ? 0 : 400 - int_Red - int_Green;
int_Blue = (int_Blue > 255) ? 255 : int_Blue; return Color.FromArgb(int_Red, int_Green, int_Blue);
}

/// <summary>
/// Create Validation Code Image
/// </summary>
private void CreateImage(string str_ValidateCode)
{
int int_ImageWidth = str_ValidateCode.Length * 22;
Random newRandom = new Random(); Bitmap theBitmap = new Bitmap(int_ImageWidth + 6 , 38);
Graphics theGraphics = Graphics.FromImage(theBitmap); theGraphics.Clear(Color.White); drawLine(theGraphics, theBitmap, newRandom);
theGraphics.DrawRectangle(new Pen(Color.LightGray, 1), 0, 0, theBitmap.Width - 1, theBitmap.Height -1 ); for (int int_index = 0; int_index < str_ValidateCode.Length; int_index++)
{            
Matrix X = new Matrix();
X.Shear((float)newRandom.Next(0,300)/1000 - 0.25f, (float)newRandom.Next(0,100)/1000 - 0.05f);
theGraphics.Transform = X;
string str_char = str_ValidateCode.Substring(int_index, 1);
System.Drawing.Drawing2D.LinearGradientBrush newBrush = new System.Drawing.Drawing2D.LinearGradientBrush(new Rectangle(0, 0, theBitmap.Width, theBitmap.Height), Color.Blue, Color.DarkRed, 1.2f, true); 
Point thePos = new Point(int_index * 21 + 1 + newRandom.Next(3), 1 + newRandom.Next(13)); Font theFont = new Font(Fonts[newRandom.Next(Fonts.Length -1)], newRandom.Next(14,18), FontStyle.Bold); theGraphics.DrawString(str_char, theFont, newBrush, thePos);
} drawPoint(theBitmap, newRandom); MemoryStream ms = new MemoryStream();
theBitmap.Save(ms, ImageFormat.Png); Response.ClearContent(); 
Response.ContentType = "image/Png";
Response.BinaryWrite(ms.ToArray());
theGraphics.Dispose();
theBitmap.Dispose();
Response.End();
} /// <summary>
/// Draw Line for noise
/// </summary>
private void drawLine(Graphics gfc,Bitmap img, Random ran)
{
for (int i = 0; i < 10; i++)
{
int x1 = ran.Next(img.Width);
int y1 = ran.Next(img.Height);
int x2 = ran.Next(img.Width);
int y2 = ran.Next(img.Height);
gfc.DrawLine(new Pen(Color.Silver), x1, y1, x2, y2);
}
} /// <summary>
/// Draw Point for noise
/// </summary>
private void drawPoint(Bitmap img, Random ran)
{
for (int i = 0; i < 30; i++)
{
int x = ran.Next(img.Width);
int y = ran.Next(img.Height);
img.SetPixel(x,y,Color.FromArgb(ran.Next()));
} } }
}

Answer 2

 Random random = new Random(); Bitmap 

Answer 3

public class VerificationCode : IHttpHandler
    {        public void ProcessRequest(HttpContext context)
        {
            //生成随机的字符串
            string randomString = GetRandomString(4);
            //将生成的字符串保存到数据库中
            BoBoContext.Current.Session["Verification_Code"] = randomString;
            //生成验证码图片
            GenerateVerificationCodeImage(randomString, context);
        }        public bool IsReusable
        {
            get
            {
                return false;
            }
        }
        /// <summary>
        /// 得到随机字符串,长度自己定义
        /// </summary>
        /// <param name="len">长度</param>
        /// <returns>指定长度的随机字符串</returns>
        private string GetRandomString(int len)
        {
            int num;
            int tem;
            Random random = new Random();
            string rtuStr = "";
            for (int i = 0; i < len; i++)
            {
                num = random.Next();
                /*
                 * 这里可以选择生成字符和数字组合的验证码
                 */
                tem = num % 10 + '0';//生成数字
                //tem = num % 26 + 'A';//生成字符
                rtuStr += Convert.ToChar(tem).ToString();
            }
            return rtuStr;
        }
        /// <summary>
        /// 生成验证码图片 
        /// </summary>
        /// <param name="randomString">随机字符串</param>
        /// <param name="context">Http上下文</param>
        private void GenerateVerificationCodeImage(string randomString, HttpContext context)
        {
            //string str = "OO00"; //前两个为字母O，后两个为数字0
            int width = Convert.ToInt32(randomString.Length * 12);    //计算图像宽度
            Bitmap img = new Bitmap(width, 23);
            Graphics gfc = Graphics.FromImage(img);           //产生Graphics对象，进行画图
            gfc.Clear(Color.White);
            DrawLine(gfc, img);
            //写验证码，需要定义Font
            Font font = new Font("arial", 12, FontStyle.Bold);
            System.Drawing.Drawing2D.LinearGradientBrush brush =
                new System.Drawing.Drawing2D.LinearGradientBrush(new Rectangle(0, 0, img.Width, img.Height), Color.DarkOrchid, Color.Blue, 1.5f, true);
            gfc.DrawString(randomString, font, brush, 3, 2);
            DrawPoint(img);
            gfc.DrawRectangle(new Pen(Color.DarkBlue), 0, 0, img.Width - 1, img.Height - 1);
            //将图像添加到页面
            MemoryStream ms = new MemoryStream();
            img.Save(ms, System.Drawing.Imaging.ImageFormat.Gif);
            //更改Http头
            context.Response.ClearContent();
            context.Response.ContentType = "image/gif";
            context.Response.BinaryWrite(ms.ToArray());
            //Dispose
            gfc.Dispose();
            img.Dispose();
            context.Response.End();
        }
        /// <summary>
        /// 为生成的验证码图片增加线条
        /// </summary>
        /// <param name="gfc">Graphics</param>
        /// <param name="img">初步生成的验证码图片</param>
        private void DrawLine(Graphics gfc, Bitmap img)
        {
            Random random = new Random();            //选择画10条线,也可以增加，也可以不要线，只要随机杂点即可
            for (int i = 0; i < 10; i++)
            {
                int x1 = random.Next(img.Width);
                int y1 = random.Next(img.Height);
                int x2 = random.Next(img.Width);
                int y2 = random.Next(img.Height);
                gfc.DrawLine(new Pen(Color.Silver), x1, y1, x2, y2);      //注意画笔一定要浅颜色，否则验证码看不清楚
            }
        }
        /// <summary>
        /// 为生成的验证码增加点
        /// </summary>
        /// <param name="img">初步生成的验证码图片</param>
        private void DrawPoint(Bitmap img)
        {            //选择画100个点,可以根据实际情况改变
            Random random = new Random();            for (int i = 0; i < 100; i++)
            {
                int x = random.Next(img.Width);
                int y = random.Next(img.Height);
                img.SetPixel(x, y, Color.FromArgb(random.Next()));//杂点颜色随机
            }            int col = random.Next();//在一次的图片中杂店颜色相同
            for (int i = 0; i < 100; i++)
            {
                int x = random.Next(img.Width);
                int y = random.Next(img.Height);
                img.SetPixel(x, y, Color.FromArgb(col));
            }
        }
    }
}

Answer 4

 using System;
 using System.IO;
 using System.Web;
 using System.Drawing;
namespace Kissogram.Common.Security
{
     //GIF验证码类
     public class Validate
     {
         //设置最少4位验证码
         private byte TrueValidateCodeCount = 4;
         public byte ValidateCodeCount
         {
             get
             {
                 return TrueValidateCodeCount;
             }
             set
             {
                 //验证码至少为3位
                 if (value > 4)
                     TrueValidateCodeCount = value;
             }
         }
         protected string ValidateCode = "";
         //是否消除锯齿
         public bool FontTextRenderingHint = false;
         //验证码字体
         public string ValidateCodeFont = "Arial";
         //验证码型号(像素)
         public float ValidateCodeSize = 13;
         public int ImageHeight = 23;
         //定义验证码中所有的字符
         public string AllChar = "1,2,3,4,5,6,7,8,9,0,A,B,C,D,E,F,G,H,I,J,K,L,M,N,O,P,Q,R,S,T,U,W,X,Y,Z";         //获得随机四位数
         private void CreateValidate()
         {
             ValidateCode = "";
             //将验证码中所有的字符保存在一个字符串数组中
             string[] CharArray = AllChar.Split(',');
             int Temp = -1;
             //生成一个随机对象
             Random RandCode = new Random();
             //根据验证码的位数循环
             for (int i = 0; i < ValidateCodeCount; i++)
             {
                 //主要是防止生成相同的验证码
                 if (Temp != -1)
                 {
                     //加入时间的刻度
                     RandCode = new Random(i * Temp * ((int)DateTime.Now.Ticks));
                 }
                 int t = RandCode.Next(35);
                 if (Temp == t)
                 {
                     //相等的话重新生成
                     CreateValidate();
                 }
                 Temp = t;
                 ValidateCode += CharArray[Temp];
             }
             //错误检测,去除超过指定位数的验证码
             if (ValidateCode.Length > TrueValidateCodeCount)
                 ValidateCode = ValidateCode.Remove(TrueValidateCodeCount);
         }
         //生成一帧的BMP图象
         private void CreateImageBmp(out Bitmap ImageFrame)
         {
             //获得验证码字符
             char[] CodeCharArray = ValidateCode.ToCharArray(0, ValidateCodeCount);
             //图像的宽度-与验证码的长度成一定比例
             int ImageWidth = (int)(TrueValidateCodeCount * ValidateCodeSize * 1.3 + 4);
             //创建一个长20，宽iwidth的图像对象
             ImageFrame = new Bitmap(ImageWidth, ImageHeight);
             //创建一个新绘图对象
             Graphics ImageGraphics = Graphics.FromImage(ImageFrame);
             //清除背景色，并填充背景色
             //Note:Color.Transparent为透明
             ImageGraphics.Clear(Color.White);
             //绘图用的字体和字号
             Font CodeFont = new Font(ValidateCodeFont, ValidateCodeSize, FontStyle.Bold);
             //绘图用的刷子大小
             Brush ImageBrush = new SolidBrush(Color.Red);
             //字体高度计算
             int FontHeight = (int)Math.Max(ImageHeight - ValidateCodeSize - 3, 2);
             //创建随机对象
             Random rand = new Random();
             //开始随机安排字符的位置，并画到图像里
             for (int i = 0; i < TrueValidateCodeCount; i++)
             {
                 //生成随机点，决定字符串的开始输出范围
                 int[] FontCoordinate = new int[2];
                 FontCoordinate[0] = (int)(i * ValidateCodeSize + rand.Next(1)) + 3;
                 FontCoordinate[1] = rand.Next(FontHeight);
                 Point FontDrawPoint = new Point(FontCoordinate[0], FontCoordinate[1]);
                 //消除锯齿操作
                 if (FontTextRenderingHint)
                     ImageGraphics.TextRenderingHint = System.Drawing.Text.TextRenderingHint.SingleBitPerPixel;
                 else
                     ImageGraphics.TextRenderingHint = System.Drawing.Text.TextRenderingHint.AntiAlias;
                 //格式化刷子属性-用指定的刷子、颜色等在指定的范围内画图
                 ImageGraphics.DrawString(CodeCharArray[i].ToString(), CodeFont, ImageBrush, FontDrawPoint);
             }
             ImageGraphics.Dispose();
         }
         //处理生成的BMP
         private void DisposeImageBmp(ref Bitmap ImageFrame)
         {
             //创建绘图对象
             Graphics ImageGraphics = Graphics.FromImage(ImageFrame);
             //创建铅笔对象
             Pen ImagePen = new Pen(Color.Red, 1);
             //创建随机对象
             Random rand = new Random();
             //创建随机点
             Point[] RandPoint = new Point[2];
             //随机画线
             for (int i = 0; i < 15; i++)
             {
                 RandPoint[0] = new Point(rand.Next(ImageFrame.Width), rand.Next(ImageFrame.Height));
                 RandPoint[1] = new Point(rand.Next(ImageFrame.Width), rand.Next(ImageFrame.Height));
                 ImageGraphics.DrawLine(ImagePen, RandPoint[0], RandPoint[1]);
             }
             ImageGraphics.Dispose();
         }
         //创建GIF动画
         private void CreateImageGif()
         {
             Bitmap ImageFrame;
             Kissogram.Drawing.Gif.AnimatedGifEncoder GifPic = new Kissogram.Drawing.Gif.AnimatedGifEncoder();
             MemoryStream BmpMemory = new MemoryStream();
             GifPic.Start();
             //确保视觉残留
             GifPic.SetDelay(5);
             //-1:no repeat,0:always repeat
             GifPic.SetRepeat(0);
             for (int i = 0; i < 20; i++)
             {
                 //创建一帧的图像
                 CreateImageBmp(out ImageFrame);
                 //生成随机线条
                 DisposeImageBmp(ref ImageFrame);
                 //输出绘图,将图像保存到指定的流
                 ImageFrame.Save(BmpMemory, System.Drawing.Imaging.ImageFormat.Png);
                 GifPic.AddFrame(Image.FromStream(BmpMemory));
                 BmpMemory = new MemoryStream();
             }
             GifPic.OutPut(ref BmpMemory);
             HttpContext.Current.Response.ClearContent();
             //配置输出类型
             HttpContext.Current.Response.ContentType = "image/Gif";
             //输出内容
             HttpContext.Current.Response.BinaryWrite(BmpMemory.ToArray());
             BmpMemory.Close();
             BmpMemory.Dispose();
         }
         //输出验证码
         public void OutPutValidate(string ValidateCodeSession)
         {
             CreateValidate();
             CreateImageGif();
             //把生成的验证码输入到SESSION
             HttpContext.Current.Session[ValidateCodeSession] = ValidateCode;
         }
     }
}/*这些代码是我在网上找到的，当时也没怎么在意。后来，我发现这个东西很吊啊！动态跳跃的验证码.给看个实例吧： 
这段源码标示是红色的是另外一个用于把单个图片封装成连续的GIF动画图片的类，所以直接有这些源码是不能创建出来的。
*/

Answer 5

using System;
using System.Data;
using System.Configuration;
using System.Collections;
using System.Web;
using System.Web.Security;
using System.Web.UI;
using System.Web.UI.WebControls;
using System.Web.UI.WebControls.WebParts;
using System.Web.UI.HtmlControls;
using System.Drawing;public partial class CheckCode : System.Web.UI.Page
{
    protected void Page_Load(object sender, EventArgs e)
    {
        CreateCheckCodeImage(GenerateCheckCode());
    }    private string GenerateCheckCode()
    {
        int number;
        char code;
        string checkCode = String.Empty;        System.Random random = new Random();        for (int i = 0; i < 4; i++)
        {
            number = random.Next();            if (number % 2 == 0)
                code = (char)('0' + (char)(number % 10));
            else
                code = (char)('A' + (char)(number % 26));            checkCode += code.ToString();
        }        Response.Cookies.Add(new HttpCookie("CheckCode", checkCode));        return checkCode;
    }    private void CreateCheckCodeImage(string checkCode)
    {
        if (checkCode == null || checkCode.Trim() == String.Empty)
            return;        System.Drawing.Bitmap image = new System.Drawing.Bitmap((int)Math.Ceiling((checkCode.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);            //画图片的背景噪音线
            for (int i = 0; i < 2; 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.Black), x1, y1, x2, y2);
            }            Font font = new System.Drawing.Font("Arial", 12, (System.Drawing.FontStyle.Bold | System.Drawing.FontStyle.Italic));
            System.Drawing.Drawing2D.LinearGradientBrush brush = new System.Drawing.Drawing2D.LinearGradientBrush(new Rectangle(0, 0, image.Width, image.Height), Color.Blue, Color.DarkRed, 1.2f, true);
            g.DrawString(checkCode, font, brush, 2, 2);            //画图片的前景噪音点
            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);            System.IO.MemoryStream ms = new System.IO.MemoryStream();
            image.Save(ms, System.Drawing.Imaging.ImageFormat.Gif);
            Response.ClearContent();
            Response.ContentType = "image/Gif";
            Response.BinaryWrite(ms.ToArray());
        }
        finally
        {
            g.Dispose();
            image.Dispose();
        }
    }
}

Answer 6

实用简介明了 就行了  不要像Google那样  太复杂 人家很反感的
代码：
using System;
using System.Data;
using System.Configuration;
using System.Collections;
using System.Web;
using System.Web.Security;
using System.Web.UI;
using System.Web.UI.WebControls;
using System.Web.UI.WebControls.WebParts;
using System.Web.UI.HtmlControls;
using System.Drawing;public partial class VerifyCode : System.Web.UI.Page
{
    protected void Page_Load(object sender, EventArgs e)
    {
        
    //验证码长度(默认6个验证码的长度)
    int length = 4;
    public int Length
    {
        get { return length; }
        set { length = value; }
    }    //验证码字体大小(为了显示扭曲效果，默认20像素，可以自行修改)
    int fontSize = 12;
    public int FontSize
    {
        get { return fontSize; }
        set { fontSize = value; }
    }    //边框补(默认1像素)
    int padding = 1;
    public int Padding
    {
        get { return padding; }
        set { padding = value; }
    }    //是否输出燥点(默认为输出)
    bool chaos = true;
    public bool Chaos
    {
        get { return chaos; }
        set { chaos = value; }
    }    //输出燥点的颜色(默认灰色)
    Color chaosColor = Color.LightGray;
    public Color ChaosColor
    {
        get { return chaosColor; }
        set { chaosColor = value; }
    }    //自定义背景色(默认白色)
    Color backgroundColor = Color.White;
    public Color BackgroundColor
    {
        get { return backgroundColor; }
        set { backgroundColor = value; }
    }    //自定义随机颜色数组
    Color[] colors = { Color.Black, Color.Red, Color.DarkBlue, Color.Green, Color.Orange, Color.Brown, Color.DarkCyan, Color.Purple };
    public Color[] Colors
    {
        get { return colors; }
        set { colors = value; }
    }    //自定义字体数组
    string[] fonts = { "Arial", "Georgia" };
    public string[] Fonts
    {
        get { return fonts; }
        set { fonts = value; }
    }    //自定义随机码字符串序列(使用逗号分隔)
    // string codeSerial = "0,1,2,3,4,5,6,7,8,9,a,b,c,d,e,f,g,h,i,j,k,l,m,n,o,p,q,r,s,t,u,v,w,x,y,z";
    string codeSerial = "0,1,2,3,4,5,6,7,8,9";    public string CodeSerial
    {
        get { return codeSerial; }
        set { codeSerial = value; }
    }    //生成校验码图片
    public Bitmap CreateImageCode(string code)
    {
        int fSize = FontSize;
        int fWidth = fSize + Padding;        int imageWidth = (int)(code.Length * fWidth) + 4 + Padding * 2;
        int imageHeight = fSize * 2 + Padding;        System.Drawing.Bitmap image = new System.Drawing.Bitmap(imageWidth, imageHeight);        Graphics g = Graphics.FromImage(image);        g.Clear(BackgroundColor);        Random rand = new Random();        //给背景添加随机生成的燥点
        if (this.Chaos)
        {
            Pen pen = new Pen(ChaosColor, 0);
            int c = Length * 15;            for (int i = 0; i < c; i++)
            {
                int x = rand.Next(image.Width);
                int y = rand.Next(image.Height);                g.DrawRectangle(pen, x, y, 1, 1);
            }
        }        int left = 0, top = 0, top1 = 1, top2 = 1;        int n1 = (imageHeight - FontSize - Padding * 2);
        int n2 = n1 / 4;
        top1 = n2;
        top2 = n2 * 2;        Font f;
        Brush b;        int cindex, findex;        //随机字体和颜色的验证码字符
        for (int i = 0; i < code.Length; i++)
        {
            cindex = rand.Next(Colors.Length - 1);
            findex = rand.Next(Fonts.Length - 1);            f = new System.Drawing.Font(Fonts[findex], fSize, System.Drawing.FontStyle.Bold);
            b = new System.Drawing.SolidBrush(Colors[cindex]);            if (i % 2 == 1)
            {
                top = top2;
            }
            else
            {
                top = top1;
            }            left = i * fWidth;            g.DrawString(code.Substring(i, 1), f, b, left, top);
        }        //画一个边框 边框颜色为Color.White
        g.DrawRectangle(new Pen(Color.White, 0), 0, 0, image.Width - 1, image.Height - 1);
        g.Dispose();        return image;
    }    //将创建好的图片输出到页面
    public void CreateImageOnPage(string code, HttpContext context)
    {
        System.IO.MemoryStream ms = new System.IO.MemoryStream();
        Bitmap image = this.CreateImageCode(code);        image.Save(ms, System.Drawing.Imaging.ImageFormat.Jpeg);        context.Response.ClearContent();
        context.Response.ContentType = "image/jpeg";
        context.Response.BinaryWrite(ms.GetBuffer());        ms.Close();
        ms = null;
        image.Dispose();
        image = null;
    }    //生成随机字符码
    public string CreateVerifyCode(int codeLen)
    {
        if (codeLen == 0)
        {
            codeLen = Length;
        }        string[] arr = CodeSerial.Split(',');        string code = "";        int randValue = -1;        Random rand = new Random(unchecked((int)DateTime.Now.Ticks));        for (int i = 0; i < codeLen; i++)
        {
            randValue = rand.Next(0, arr.Length - 1);            code += arr[randValue];
        }        return code;
    }    public string CreateVerifyCode()
    {
        return CreateVerifyCode(0);
    }
}

Answer 7

public class VerificationCode : IHttpHandler 
    {         public void ProcessRequest(HttpContext context) 
        { 
            //生成随机的字符串 
            string randomString = GetRandomString(4); 
            //将生成的字符串保存到数据库中 
            BoBoContext.Current.Session["Verification_Code"] = randomString; 
            //生成验证码图片 
            GenerateVerificationCodeImage(randomString, context); 
        }         public bool IsReusable 
        { 
            get 
            { 
                return false; 
            } 
        } 
        /// <summary> 
        /// 得到随机字符串,长度自己定义 
        /// </summary> 
        /// <param name="len">长度 </param> 
        /// <returns>指定长度的随机字符串 </returns> 
        private string GetRandomString(int len) 
        { 
            int num; 
            int tem; 
            Random random = new Random(); 
            string rtuStr = ""; 
            for (int i = 0; i < len; i++) 
            { 
                num = random.Next(); 
                /* 
                * 这里可以选择生成字符和数字组合的验证码 
                */ 
                tem = num % 10 + '0';//生成数字 
                //tem = num % 26 + 'A';//生成字符 
                rtuStr += Convert.ToChar(tem).ToString(); 
            } 
            return rtuStr; 
        } 
        /// <summary> 
        /// 生成验证码图片 
        /// </summary> 
        /// <param name="randomString">随机字符串 </param> 
        /// <param name="context">Http上下文 </param> 
        private void GenerateVerificationCodeImage(string randomString, HttpContext context) 
        { 
            //string str = "OO00"; //前两个为字母O，后两个为数字0 
            int width = Convert.ToInt32(randomString.Length * 12);    //计算图像宽度 
            Bitmap img = new Bitmap(width, 23); 
            Graphics gfc = Graphics.FromImage(img);          //产生Graphics对象，进行画图 
            gfc.Clear(Color.White); 
            DrawLine(gfc, img); 
            //写验证码，需要定义Font 
            Font font = new Font("arial", 12, FontStyle.Bold); 
            System.Drawing.Drawing2D.LinearGradientBrush brush = 
                new System.Drawing.Drawing2D.LinearGradientBrush(new Rectangle(0, 0, img.Width, img.Height), Color.DarkOrchid, Color.Blue, 1.5f, true); 
            gfc.DrawString(randomString, font, brush, 3, 2); 
            DrawPoint(img); 
            gfc.DrawRectangle(new Pen(Color.DarkBlue), 0, 0, img.Width - 1, img.Height - 1); 
            //将图像添加到页面 
            MemoryStream ms = new MemoryStream(); 
            img.Save(ms, System.Drawing.Imaging.ImageFormat.Gif); 
            //更改Http头 
            context.Response.ClearContent(); 
            context.Response.ContentType = "image/gif"; 
            context.Response.BinaryWrite(ms.ToArray()); 
            //Dispose 
            gfc.Dispose(); 
            img.Dispose(); 
            context.Response.End(); 
        } 
        /// <summary> 
        /// 为生成的验证码图片增加线条 
        /// </summary> 
        /// <param name="gfc">Graphics </param> 
        /// <param name="img">初步生成的验证码图片 </param> 
        private void DrawLine(Graphics gfc, Bitmap img) 
        { 
            Random random = new Random();             //选择画10条线,也可以增加，也可以不要线，只要随机杂点即可 
            for (int i = 0; i < 10; i++) 
            { 
                int x1 = random.Next(img.Width); 
                int y1 = random.Next(img.Height); 
                int x2 = random.Next(img.Width); 
                int y2 = random.Next(img.Height); 
                gfc.DrawLine(new Pen(Color.Silver), x1, y1, x2, y2);      //注意画笔一定要浅颜色，否则验证码看不清楚 
            } 
        } 
        /// <summary> 
        /// 为生成的验证码增加点 
        /// </summary> 
        /// <param name="img">初步生成的验证码图片 </param> 
        private void DrawPoint(Bitmap img) 
        {             //选择画100个点,可以根据实际情况改变 
            Random random = new Random();             for (int i = 0; i < 100; i++) 
            { 
                int x = random.Next(img.Width); 
                int y = random.Next(img.Height); 
                img.SetPixel(x, y, Color.FromArgb(random.Next()));//杂点颜色随机 
            }             int col = random.Next();//在一次的图片中杂店颜色相同 
            for (int i = 0; i < 100; i++) 
            { 
                int x = random.Next(img.Width); 
                int y = random.Next(img.Height); 
                img.SetPixel(x, y, Color.FromArgb(col)); 
            } 
        } 
    } 
}都差不多啊

Answer 8

新建CheckCode.aspxusing System;
using System.Drawing;public partial class ValidateCode : System.Web.UI.Page 
{
    protected void Page_Load(object sender, EventArgs e)
    {
        this.CreateCheckCodeImage(GenerateCheckCode());
    }
    private string GenerateCheckCode()
    {
        int number;
        char code;
        string checkCode = String.Empty;        System.Random random = new Random();        for (int i = 0; i < 6; i++)
        {
            number = random.Next();            if (number % 2 == 0)
                code = (char)('0' + (char)(number % 10));
            else
                code = (char)('A' + (char)(number % 26));            checkCode += code.ToString();
        }
        Session["CheckCode"] = checkCode;        //Response.Cookies.Add(new HttpCookie("CheckCode", checkCode));        return checkCode;
    }    private void CreateCheckCodeImage(string checkCode)
    {
        if (checkCode == null || checkCode.Trim() == String.Empty)
            return;        System.Drawing.Bitmap image = new System.Drawing.Bitmap((int)Math.Ceiling((checkCode.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);            //画图片的背景噪音线
            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 System.Drawing.Font("Arial", 12, (System.Drawing.FontStyle.Bold | System.Drawing.FontStyle.Italic));
            System.Drawing.Drawing2D.LinearGradientBrush brush = new System.Drawing.Drawing2D.LinearGradientBrush(new Rectangle(0, 0, image.Width, image.Height), Color.Blue, Color.DarkRed, 1.2f, true);
            g.DrawString(checkCode, font, brush, 2, 2);            //画图片的前景噪音点
            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);            System.IO.MemoryStream ms = new System.IO.MemoryStream();
            image.Save(ms, System.Drawing.Imaging.ImageFormat.Gif);
            Response.ClearContent();
            Response.ContentType = "image/Gif";
            Response.BinaryWrite(ms.ToArray());
        }
        finally
        {
            g.Dispose();
            image.Dispose();
        }
    }}使用，*.aspx内
<asp:Image ID="imgCheckCode" runat="server" ImageUrl="~/CheckCode.aspx" />

Answer 9

using System;
using System.Collections;
using System.ComponentModel;
using System.Data;
using System.Web;
using System.Web.SessionState;
using System.Web.UI;
using System.Web.UI.WebControls;
using System.Web.UI.HtmlControls;using System.Drawing;
using System.Drawing.Imaging;
using System.Drawing.Text;/**///// <summary>
/// 页面验证码程序
/// 使用：在页面中加入HTML代码 <img src="VerifyCode.aspx">
/// </summary>
public partial class VerifyCode : System.Web.UI.Page
...{
    static string[] FontItems  = new string[] ...{   "Arial", 
                                                  "Helvetica", 
                                                  "Geneva", 
                                                  "sans-serif", 
                                                  "Verdana"
                                              };    static Brush[] BrushItems = new Brush[] ...{     Brushes.OliveDrab,
                                                  Brushes.ForestGreen,
                                                  Brushes.DarkCyan,
                                                  Brushes.LightSlateGray,
                                                  Brushes.RoyalBlue,
                                                  Brushes.SlateBlue,
                                                  Brushes.DarkViolet,
                                                  Brushes.MediumVioletRed,
                                                  Brushes.IndianRed,
                                                  Brushes.Firebrick,
                                                  Brushes.Chocolate,
                                                  Brushes.Peru,
                                                  Brushes.Goldenrod
                                            };    static string[] BrushName = new string[] ...{    "OliveDrab",
                                                  "ForestGreen",
                                                  "DarkCyan",
                                                  "LightSlateGray",
                                                  "RoyalBlue",
                                                  "SlateBlue",
                                                  "DarkViolet",
                                                  "MediumVioletRed",
                                                  "IndianRed",
                                                  "Firebrick",
                                                  "Chocolate",
                                                  "Peru",
                                                  "Goldenrod"
                                             };    private static Color BackColor    =  Color.White;
    private static Pen   BorderColor  =  Pens.DarkGray;
    private static int   Width        =  52;
    private static int   Height       =  21;    private Random _random;
    private string _code;
    private int    _brushNameIndex;    
    override protected void OnInit(EventArgs e)
    ...{
        //
        // CODEGEN: This call is required by the ASP.NET Web Form Designer.
        //
        //InitializeComponent();
        //base.OnInit(e);
    }
    
    /**//**//**//// <summary>
    /// Required method for Designer support - do not modify
    /// the contents of this method with the code editor.
    /// </summary>
    private void InitializeComponent()
    ...{    
        //this.Load += new System.EventHandler(this.Page_Load);
    }    /**//// <summary>
    /// 
    /// </summary>
    /// <param name="sender"></param>
    /// <param name="e"></param>
    public void Page_Load(object sender, System.EventArgs e)
    ...{
        if (!IsPostBack)
        ...{
            //
            // TODO : initialize
            //
            this._random = new Random();
            this._code = GetRandomCode();            //
            // TODO : use Session["code"] save the VerifyCode
            //
            Session["code"] = this._code;            //
            // TODO : output Image
            //
            this.SetPageNoCache();
            this.OnPaint();
        }
    }
    /**//**//**//// <summary>
    /// 设置页面不被缓存
    /// </summary>
    private void SetPageNoCache()
    ...{
        Response.Buffer = true;
        Response.ExpiresAbsolute = System.DateTime.Now.AddSeconds(-1);
        Response.Expires = 0;
        Response.CacheControl = "no-cache";
        Response.AppendHeader("Pragma","No-Cache");
    }    /**//**//**//// <summary>
    /// 取得一个 4 位的随机码
    /// </summary>
    /// <returns></returns>
    private string GetRandomCode()
    ...{
        return Guid.NewGuid().ToString().Substring(0, 4);
    }    /**//**//**//// <summary>
    /// 随机取一个字体
    /// </summary>
    /// <returns></returns>
    private Font GetFont()
    ...{
        int fontIndex = _random.Next(0, FontItems.Length);
        FontStyle fontStyle = GetFontStyle(_random.Next(0, 2));
        return new Font(FontItems[fontIndex], 12, fontStyle);
    }    /**//**//**//// <summary>
    /// 取一个字体的样式
    /// </summary>
    /// <param name="index"></param>
    /// <returns></returns>
    private FontStyle GetFontStyle(int index)
    ...{
        switch (index)
        ...{
            case 0:
                return FontStyle.Bold;
            case 1:
                return FontStyle.Italic;
            default:
                return FontStyle.Regular;
        }
    }    /**//**//**//// <summary>
    /// 随机取一个笔刷
    /// </summary>
    /// <returns></returns>
    private Brush GetBrush()
    ...{
        int brushIndex = _random.Next(0, BrushItems.Length);
        _brushNameIndex = brushIndex;
        return BrushItems[brushIndex];
    }    /**//**//**//// <summary>
    /// 绘画事件
    /// </summary>
    private void OnPaint()
    ...{
        Bitmap objBitmap = null;
        Graphics g = null;        try
        ...{
            objBitmap = new Bitmap(Width, Height);
            g = Graphics.FromImage(objBitmap);            Paint_Background(g);
            Paint_Text(g);
            Paint_TextStain(objBitmap);
            Paint_Border(g);            objBitmap.Save(Response.OutputStream, ImageFormat.Gif);
            Response.ContentType = "image/gif";
        }
        catch ...{}
        finally
        ...{
            if (null != objBitmap)
                objBitmap.Dispose();
            if (null != g)
                g.Dispose();
        }
    }    /**//**//**//// <summary>
    /// 绘画背景颜色
    /// </summary>
    /// <param name="g"></param>
    private void Paint_Background(Graphics g)
    ...{
        g.Clear(BackColor);
    }    /**//**//**//// <summary>
    /// 绘画边框
    /// </summary>
    /// <param name="g"></param>
    private void Paint_Border(Graphics g)
    ...{
        g.DrawRectangle(BorderColor, 0, 0, Width - 1, Height - 1);
    }    /**//**//**//// <summary>
    /// 绘画文字
    /// </summary>
    /// <param name="g"></param>
    private void Paint_Text(Graphics g)
    ...{
        g.DrawString(_code, GetFont(), GetBrush(), 3, 1);
    }    /**//**//**//// <summary>
    /// 绘画文字噪音点
    /// </summary>
    /// <param name="g"></param>
    private void Paint_TextStain(Bitmap b)
    ...{
        for (int n=0; n<30; n++)
        ...{
            int x = _random.Next(Width);
            int y = _random.Next(Height);
            b.SetPixel(x, y, Color.FromName(BrushName[_brushNameIndex]));
        }    }
}  2 页面引用：<asp:Image ID="getcode" src="VerifyCode.aspx" runat="server" />一般需要同时提供刷新功能(看不清楚换一张)，代码如下    <asp:Image ID="getcode" src="VerifyCode.aspx" runat="server" />&nbsp;&nbsp;<A href="javascript:getimgcode()">刷新验证码</A>
 如使用了母版页，则用如下代码：<img ID="getcode" alt="" src="VerifyCode.aspx" />&nbsp;<%--<asp:Image ID="getcode" src="VerifyCode.aspx" runat="server" />--%>
&nbsp;&nbsp;<A href="javascript:getimgcode()">刷新验证码</A>

Answer 10

there is so much code, do you fint satisfactory answer?
.

Answer 11

原创作品：http://blog.csdn.net/aimeast/archive/2010/02/11/5306074.aspx

Answer 12

using System;
using System.Data;
using System.Configuration;
using System.Collections;
using System.Web;
using System.Web.Security;
using System.Web.UI;
using System.Web.UI.WebControls;
using System.Web.UI.WebControls.WebParts;
using System.Web.UI.HtmlControls;
using System.Drawing;public partial class common_CheckCode : System.Web.UI.Page
{
    private void Page_Load(object sender, System.EventArgs e)
    {        
        this.CreateCheckCodeImage(GenerateCheckCode());        
    }    private string GenerateCheckCode()
    {
        int number;
        char code;
        string checkCode = String.Empty;        System.Random random = new Random();        for (int i = 0; i < 4; i++)
        {
            number = random.Next();            if (number % 2 == 0)
                code = (char)('0' + (char)(number % 10));
            else
                code = (char)('A' + (char)(number % 26));            checkCode += code.ToString();
        }        Session["checkcode"] = checkCode;
        
        return checkCode;
    }    private void CreateCheckCodeImage(string checkCode)
    {
        if (checkCode == null || checkCode.Trim() == String.Empty)
            return;
       
        System.Drawing.Bitmap image = new System.Drawing.Bitmap((int)Math.Ceiling((checkCode.Length * 12.5)), 20);
        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);            //画图片的背景噪音线
            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 System.Drawing.Font("Arial", 12, (System.Drawing.FontStyle.Bold | System.Drawing.FontStyle.Italic));
            System.Drawing.Drawing2D.LinearGradientBrush brush = new System.Drawing.Drawing2D.LinearGradientBrush(new Rectangle(0, 0, image.Width, image.Height), Color.Blue, Color.DarkRed, 1.2f, true);
            g.DrawString(checkCode, font, brush, 2, 2);            //画图片的前景噪音点
            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);            System.IO.MemoryStream ms = new System.IO.MemoryStream();
            image.Save(ms, System.Drawing.Imaging.ImageFormat.Gif);
            Response.ClearContent();
            Response.ContentType = "image/Gif";
            Response.BinaryWrite(ms.ToArray());
        }
        finally
        {
            g.Dispose();
            image.Dispose();            
        }
    }
}

Answer 13

人生- CSDN社区 ...