• asp.net的验证码插件及方法、ashx验证码一般处理程序


    需要引入一个ashx的一般处理程序!
    把这个程序在前台当作一个图片使用就可以!

    前台代码:

    <td>
             <img title="看不清?" style=" cursor:pointer ;vertical-align:middle" width="45px" src="../ValidateCode.ashx"   onclick="this.src='../ValidateCode.ashx?_='+Math.random()" />
    </td>


    cursor:pointer  光标呈现为指示链接的指针(一只手)
    onclick             点击切换图片
    Math.random()随机数,改变切换地址,有些浏览器点击的时候不自动切换,直接调用缓存文件(如IE)

    验证码一般处理程序ashx:
    不知道为什么传不上来啊附件,我就把代码贴上来吧,大家回去用这个代码建立一个ashx的文件就OK了

    建议验证码存到【session】里面,下面的代码是存到session里的(使用其他方法的可以注释掉context.Session["code"] = code;)

    //一般处理程序中使用session,必须实现一个接口
    首先添加一个命名空间“using System.Web.SessionState;”
    我把我的后台登录的判断处代码贴到下面,也许对大家的理解有帮助。。。。

    <%@ WebHandler Language="C#" Class="ValidateCode" %>
    
    using System;
    using System.Web;
    using System.Drawing;
    using System.Web.SessionState;
    public class ValidateCode : IHttpHandler, IRequiresSessionState {
    
        public void ProcessRequest(HttpContext context)
        {
            context.Response.ContentType = "image/jpeg";
            string code = GetRndStr();//生成4个随机的字符
            
            //记录生成的验证码到session
            context.Session["code"] = code;
      
            using (Bitmap img = CreateImages(code, "ch"))
            {
                img.Save(context.Response.OutputStream, System.Drawing.Imaging.ImageFormat.Jpeg);
            }
        }
    
        public bool IsReusable
        {
            get
            {
                return false;
            }
        }
        /// <summary>
        /// 数字随机数
        /// </summary>
        /// <returns></returns>
        private string GetRndNum()
        {
            string code = string.Empty;
            Random random = new Random();
            for (int i = 0; i < 4; i++)
            {
                code += random.Next(9);
            }
            return code;
        }
        /// <summary>
        ///  英文随机
        /// </summary>
        /// <returns></returns>
        private string GetRndStr()
        {
            string Vchar = "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[] VcArray = Vchar.Split(',');
            string checkCode = string.Empty;
            Random rand = new Random();
            for (int i = 0; i < 4; i++)
            {
                int t = rand.Next(VcArray.Length);
                checkCode += VcArray[t];
            }
            return checkCode;
        }
        /// <summary>
        /// 中文随机
        /// </summary>
        /// <returns></returns>
        private string GetRndCh()
        {
            System.Text.Encoding gb = System.Text.Encoding.Default;//获取GB2312编码页(表)
            object[] bytes = CreateRegionCode(4);//生4个随机中文汉字编码
            string[] str = new string[4];
            System.Text.StringBuilder sb = new System.Text.StringBuilder();
            for (int i = 0; i < 4; i++)
            {
                //根据汉字编码的字节数组解码出中文汉字
                str[i] = gb.GetString((byte[])Convert.ChangeType(bytes[i], typeof(byte[])));
                sb.Append(str[i].ToString());
            }
            return sb.ToString();
        }
        /// <summary>
        /// 产生随机中文字符
        /// </summary>
        /// <param name="strlength"></param>
        /// <returns></returns>
        private static object[] CreateRegionCode(int strlength)
        {
            //定义一个字符串数组储存汉字编码的组成元素
            string[] rBase = new String[16] { "0", "1", "2", "3", "4", "5", "6", "7", "8", "9", "a", "b", "c", "d", "e", "f" };
            Random rnd = new Random();
            object[] bytes = new object[strlength];
    
            for (int i = 0; i < strlength; i++)
            {
                //区位码第1位
                int r1 = rnd.Next(11, 14);
                string str_r1 = rBase[r1].Trim();
                //区位码第2位
                rnd = new Random(r1 * unchecked((int)DateTime.Now.Ticks) + i);
                int r2;
                if (r1 == 13)
                {
                    r2 = rnd.Next(0, 7);
                }
                else
                {
                    r2 = rnd.Next(0, 16);
                }
                string str_r2 = rBase[r2].Trim();
    
                //区位码第3位
                rnd = new Random(r2 * unchecked((int)DateTime.Now.Ticks) + i);//更换随机种子
                int r3 = rnd.Next(10, 16);
                string str_r3 = rBase[r3].Trim();
    
                //区位码第4位
                rnd = new Random(r3 * unchecked((int)DateTime.Now.Ticks) + i);
                int r4;
                if (r3 == 10)
                {
                    r4 = rnd.Next(1, 16);
                }
                else if (r3 == 15)
                {
                    r4 = rnd.Next(0, 15);
                }
                else
                {
                    r4 = rnd.Next(0, 16);
                }
                string str_r4 = rBase[r4].Trim();
                //定义两个字节变量存储产生的随机汉字区位码
                byte byte1 = Convert.ToByte(str_r1 + str_r2, 16);
                byte byte2 = Convert.ToByte(str_r3 + str_r4, 16);
    
                //将两个字节变量存储在字节数组中
                byte[] str_r = new byte[] { byte1, byte2 };
    
                //将产生的一个汉字的字节数组放入object数组中
                bytes.SetValue(str_r, i);
            }
            return bytes;
        }
        /// <summary>
        /// 画图片的背景图+干扰线 
        /// </summary>
        /// <param name="checkCode"></param>
        /// <returns></returns>
        private Bitmap CreateImages(string checkCode, string type)
        {
            int step = 0;
            if (type == "ch")
            {
                step = 5;//中文字符,边界值做大
            }
            int iwidth = (int)(checkCode.Length * (13 + step));
            System.Drawing.Bitmap image = new System.Drawing.Bitmap(iwidth, 33);
            Graphics g = Graphics.FromImage(image);
            g.Clear(Color.White);//清除背景色
            Color[] c = { Color.Black, Color.Red, Color.DarkBlue, Color.Green, Color.Orange, Color.Brown, Color.DarkCyan, Color.Purple };//定义随机颜色
            string[] font = { "Verdana", "Microsoft Sans Serif", "Comic Sans MS", "Arial", "宋体" };
            Random rand = new Random();
    
            for (int i = 0; i < 50; i++)
            {
                int x1 = rand.Next(image.Width);
                int x2 = rand.Next(image.Width);
                int y1 = rand.Next(image.Height);
                int y2 = rand.Next(image.Height);
                g.DrawLine(new Pen(Color.LightGray, 1), x1, y1, x2, y2);//根据坐标画线
            }
    
            for (int i = 0; i < checkCode.Length; i++)
            {
                int cindex = rand.Next(7);
                int findex = rand.Next(5);
    
                Font f = new System.Drawing.Font(font[findex], 15, System.Drawing.FontStyle.Bold);
                Brush b = new System.Drawing.SolidBrush(c[cindex]);
                int ii = 4;
                if ((i + 1) % 2 == 0)
                {
                    ii = 2;
                }
                g.DrawString(checkCode.Substring(i, 1), f, b, 3 + (i * (12 + step)), ii);
    
            }
            g.DrawRectangle(new Pen(Color.Black, 0), 0, 0, image.Width - 1, image.Height - 1);
            System.IO.MemoryStream ms = new System.IO.MemoryStream();
            return image;
        }
    }
    View Code

    判断session后天代码:

           protected void btnLogin_Click(object sender, EventArgs e)
            {
    
                //学生  1  老师 2
                string type = ddl.SelectedValue;
                string no = txtNo.Text.Trim();
                string pwd = txtPwd.Text.Trim();
                //md5加密
                pwd =   Common.GetMd5(pwd);
    
    
                string code = txtCode.Text.Trim();
                 
                //验证码正确    因为session有过期失效的问题,
               //ps:session在服务器上默认保存20分钟
                if (Session["code"] != null &&  code.ToLower() == Session["code"].ToString().ToLower())
                {
                    //
                    Session.Remove("code");
                    string msg;
                    //学生
                    if (type == "1")
                    { //判断用户名密码是否正确
                        ItcastOCSS.BLL.Student bll = new ItcastOCSS.BLL.Student();
                        ItcastOCSS.Model.Student stu = new ItcastOCSS.Model.Student();
                        if (bll.Login(no, pwd, out msg, out stu))
                        {
                            //记录登陆成功的状态
                            Session["user"] = stu;
                            //跳转
                            Response.Redirect("Student/Index.aspx");
                        }
                        lblMsg.Text = msg;
                    }
                    else if (type == "2")
                    { 
                        //老师
                        ItcastOCSS.BLL.Teacher bll = new ItcastOCSS.BLL.Teacher();
                        ItcastOCSS.Model.Teacher tea = new ItcastOCSS.Model.Teacher();
                        if (bll.Login(no, pwd, out msg, out tea))
                        {
                            Session["user"] = tea;
                            //跳转
                            if (tea.TIsAdmin == 1)
                            {
                                //管理员
                                Response.Redirect("Admin/Index.aspx");
                            }
                            else if(tea.TIsAdmin == 0)
                            { 
                                //老师
                                Response.Redirect("Teacher/Index.aspx");
                            }
                        }
                    }
                    
                }
                else
                { 
                    //验证码错误
                    lblMsg.Text = "验证码错误";
                }
                
            }
    View Code


    另外一个

    using System;
    using System.Collections.Generic;
    using System.Drawing;
    using System.Drawing.Drawing2D;
    using System.Drawing.Imaging;
    using System.IO;
    using System.Linq;
    using System.Text;
    using System.Threading.Tasks;
    using System.Web;
    
    namespace CZBK.ItcastProject.Common
    {
        public class ValidateCode
        {
            public ValidateCode()
            {
            }
            /// <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 CreateValidateCode(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(string validateCode, HttpContext context)
            {
                Bitmap image = new Bitmap((int)Math.Ceiling(validateCode.Length * 12.0), 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));
                    //渐变.
                    LinearGradientBrush brush = new LinearGradientBrush(new Rectangle(0, 0, image.Width, image.Height),
                     Color.Blue, Color.DarkRed, 1.2f, true);
                    g.DrawString(validateCode, 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);
                    //输出图片流
                    context.Response.Clear();
                    context.Response.ContentType = "image/jpeg";
                    context.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 * 12.0);
            }
            /// <summary>
            /// 得到验证码的高度
            /// </summary>
            /// <returns></returns>
            public static double GetImageHeight()
            {
                return 22.5;
            }
        }
    }
    View Code

    本文转自:http://www.nbcoder.net/thread-337-1-1.html

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  • 原文地址:https://www.cnblogs.com/xiaoshi657/p/4113777.html
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