验证码C#实现代码

using System;
using System.Data;
using System.Configuration;
using System.Web;
using System.Web.Security;
using System.Web.UI;
using System.Web.UI.WebControls;
using System.Web.UI.HtmlControls;
using System.Drawing;
//powered by http://outofmemory.cn/
namespace AppUtility.Tools
{
    /// <summary>
    /// VerifyCode 的摘要说明。
    /// </summary>
    public class VerifyCodeImgHelper
    {
        public VerifyCodeImgHelper()
        {
            //
            // TODO: 在此处添加构造函数逻辑
            //
        }

    #region 验证码长度(默认4个验证码的长度)
    int length = 4;
    public int Length
    {
      get { return length; }
      set { length = value; }
    }
    #endregion

    #region 验证码字体大小默认11像素
    int fontSize = 11;
    public int FontSize
    {
        get { return fontSize; }
        set { fontSize = value; }
    }
    #endregion

    #region 边框补
    int padding = 1;
    public int Padding
    {
        get { return padding; }
        set { padding = value; }
    }
    #endregion

    #region 是否输出燥点(默认不输出)
    bool chaos = true;
    public bool Chaos
    {
        get { return chaos; }
        set { chaos = value; }
    }
    #endregion

    #region 输出燥点的颜色(默认灰色)
    Color chaosColor = Color.LightGray;
    public Color ChaosColor
    {
        get { return chaosColor; }
        set { chaosColor = value; }
    }
    #endregion

    #region 自定义背景色(默认白色)
    Color backgroundColor = Color.White;
    public Color BackgroundColor
    {
        get { return backgroundColor; }
        set { backgroundColor = value; }
    }
    #endregion

    #region 自定义随机颜色数组
    Color[] colors = { Color.Black, Color.Red, Color.DarkBlue, Color.Green, Color.DarkMagenta, Color.Brown, Color.DarkCyan, Color.Purple };
    public Color[] Colors
    {
        get { return colors; }
        set { colors = value; }
    }
    #endregion

    #region 自定义字体数组
    string[] fonts = { "Gautami","Tahoma","宋体" };
    public string[] Fonts
    {
        get { return fonts; }
        set { fonts = value; }
    }
    #endregion

    #region 自定义随机码字符串序列(使用逗号分隔)
    string codeSerial = "a,b,c,d,e,f,g,h,i,j,k,m,n,p,q,2,3,4,5,s,t,u,v,w,x,y,z,6,7,8,A,B,D,E,F,G,H,K,M,N,Q";//
    public string CodeSerial
    {
        get { return codeSerial; }
        set { codeSerial = value; }
    }
    #endregion

    #region 生成校验码图片
    public Bitmap CreateImageCode(string code)
    {
        int fSize = FontSize;
        int fWidth = fSize + Padding;
        int imageWidth = 60;
        int imageHeight = 25;
        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 * 10;
            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;

        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 = 2;
            }
            else
            {
                top = 1;
            }

            left = i * fWidth;
            g.DrawString(code.Substring(i, 1), f, b, left, top);
        }
        //画一个边框边框颜色为Color.Gainsboro
        g.DrawRectangle(new Pen(Color.Gainsboro, 0), 0, 0, image.Width - 1, image.Height - 1);
        g.Dispose();
        return image;
    }
    #endregion

    #region 将创建好的图片输出到页面
    public void CreateImageOnPage(string code, HttpContext context)
    {
        using (System.IO.MemoryStream ms = new System.IO.MemoryStream())
        {
            using (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();
            }
        }
    }
    #endregion

    #region 生成随机字符码
    public string CreateVerifyCode(int codeLen)
    {
        if (codeLen == 0)
        {
            codeLen = Length;
        }
        string[] arr = CodeSerial.Split(',');
        string code = "";
        int temp = -1;
        Random rand = new Random();
        for (int i = 0; i < codeLen; i++)
        {
            if (temp != -1)
            {
                rand = new Random(temp * i * ((int)DateTime.Now.Ticks));
            }

            int t = rand.Next(arr.Length-1);

            while (temp == t)
            {
                t = rand.Next(arr.Length-1);
            }

            temp = t;
            code += arr[t];
        }

        return code;
    }

    #endregion

}

}</pre>