验证码生成类

using System.Collections.Generic; 
using System.Text; 
using System.Threading; 
using System.Drawing; 
using System.Drawing.Drawing2D;  
 
namespace FreeOH.Validate 
{ 
    /// <summary> 
    /// 本类用于产生随机的验证码 
    /// </summary> 
    public class ValidationCode 
    { 
        //用户存取验证码字符串 
        public string validationCode = String.Empty;  
 
        Graphics g = null;  
 
        int bgWidth = 0; 
        int bgHeight = 0;  
 
        public string FontFace = "Comic Sans MS"; 
        public int FontSize = 9; 
        public Color foreColor = Color.FromArgb(220, 220, 220); 
        public Color backColor = Color.FromArgb(190, 190, 190); 
        public Color mixedLineColor = Color.FromArgb(220, 220, 220); 
        public int mixedLineWidth = 1; 
        public int mixedLineCount = 5;  
 
 
        #region 根据指定长度，返回随机验证码 
        /// <summary> 
        /// 根据指定长度，返回随机验证码 
        /// </summary> 
        /// <param name="length">制定长度</param> 
        /// <returns>随即验证码</returns> 
        public string Next(int length) 
        { 
            this.validationCode = GetRandomCode(length); 
            return this.validationCode; 
        } 
        #endregion  
 
 
        #region 根据指定长度及背景图片样式，返回带有随机验证码的图片对象 
        /// <summary> 
        /// 根据指定长度及背景图片样式，返回带有随机验证码的图片对象 
        /// </summary> 
        /// <param name="length">指定长度</param> 
        /// <param name="hatchStyle">背景图片样式</param> 
        /// <returns>Image对象</returns> 
        public Image NextImage(int length, HatchStyle hatchStyle, bool allowMixedLines) 
        { 
            this.validationCode = GetRandomCode(length);  
 
            //校验码字体 
            Font myFont = new Font(FontFace, FontSize);  
 
            //根据校验码字体大小算出背景大小 
            bgWidth = (int)myFont.Size * length + 4; 
            bgHeight = (int)myFont.Size * 2; 
            //生成背景图片 
            Bitmap myBitmap = new Bitmap(bgWidth, bgHeight);  
 
            g = Graphics.FromImage(myBitmap);  
 
 
            this.DrawBackground(hatchStyle); 
            this.DrawValidationCode(this.validationCode,myFont); 
            if (allowMixedLines) 
                this.DrawMixedLine();  
 
            return (Image)myBitmap; 
        } 
        #endregion  
 
 
        #region 内部方法：绘制验证码背景 
        private void DrawBackground(HatchStyle hatchStyle) 
        { 
            //设置填充背景时用的笔刷 
            HatchBrush hBrush = new HatchBrush(hatchStyle, backColor);  
 
            //填充背景图片 
            g.FillRectangle(hBrush, 0, 0, this.bgWidth, this.bgHeight); 
        } 
        #endregion  
 
 
        #region 内部方法：绘制验证码 
        private void DrawValidationCode(string vCode, Font font) 
        { 
            g.DrawString(vCode, font, new SolidBrush(this.foreColor), 2, 2); 
        } 
        #endregion  
 
 
        #region 内部方法：绘制干扰线条 
        /// <summary> 
        /// 绘制干扰线条 
        /// </summary> 
        private void DrawMixedLine() 
        { 
            for (int i = 0; i < mixedLineCount; i++) 
            { 
                g.DrawBezier(new Pen(new SolidBrush(mixedLineColor), mixedLineWidth), RandomPoint(), RandomPoint(), RandomPoint(), RandomPoint()); 
            } 
        } 
        #endregion  
 
        #region 内部方法：返回指定长度的随机验证码字符串 
        /// <summary> 
        /// 根据指定大小返回随机验证码 
        /// </summary> 
        /// <param name="length">字符串长度</param> 
        /// <returns>随机字符串</returns> 
        private string GetRandomCode(int length) 
        { 
            StringBuilder sb = new StringBuilder(6);  
 
            for (int i = 0; i < length; i++) 
            { 
                sb.Append(Char.ConvertFromUtf32(RandomAZ09())); 
            }  
 
            return sb.ToString(); 
        } 
        #endregion  
 
 
        #region 内部方法：产生随机数和随机点  
 
        /// <summary> 
        /// 产生0-9A-Z的随机字符代码 
        /// </summary> 
        /// <returns>字符代码</returns> 
        private int RandomAZ09() 
        { 
            Thread.Sleep(15); 
            int result = 48; 
            Random ram = new Random(); 
            int i = ram.Next(2);  
 
            switch (i) 
            { 
                case 0: 
                    result = ram.Next(48, 58); 
                    break; 
                case 1: 
                    result = ram.Next(65, 91); 
                    break; 
            }  
 
            return result; 
        }  
 
        /// <summary> 
        /// 返回一个随机点，该随机点范围在验证码背景大小范围内 
        /// </summary> 
        /// <returns>Point对象</returns> 
        private Point RandomPoint() 
        { 
            Thread.Sleep(15); 
            Random ram = new Random(); 
            Point point = new Point(ram.Next(this.bgWidth), ram.Next(this.bgHeight)); 
            return point; 
        } 
        #endregion 
    } 
} 

把图片输入到页面

System.IO.MemoryStream ms = new System.IO.MemoryStream(); 

    image.Save(ms, System.Drawing.Imaging.ImageFormat.Gif); 

    System.Web.HttpContext.Current.Response.ClearContent(); 

    System.Web.HttpContext.Current.Response.ContentType = "image/Gif"; 

    System.Web.HttpContext.Current.Response.BinaryWrite(ms.ToArray()); 

生成验证码 点击可刷新

先建一张生成验证码的网页CheckCode.aspx

CheckCode.aspx.cs代码如下添加引用:

using System.IO;

using System.Drawing;

using System.Drawing.Imaging;

using System.Drawing.Drawing2D;

然后是显示验证码的页面的html中加入

<img src="CheckCode.aspx" id="yzm" alt="点击刷新" />

在</head>之前一行加入javascript脚本语言如下(当然写在JS文件里面更好):

function reloadcode(){ document.getElementById("yzm").src ="CheckCode.aspx";}