C#.NETMVC验证码

生成图片的帮助类

using System;
using System.Drawing;
using System.Drawing.Drawing2D;
using System.Drawing.Imaging;
using System.IO;

namespace WebApplication1.Controllers
{
    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;
        }

        //C# MVC 升级版
        /// <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 byte[] CreateValidateGraphic(string validateCode)
        {
            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));
                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
                return 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;
        }
    }
}

控制器的写法 (控制器名称LoginController)

using System;
using System.Collections.Generic;
using System.Linq;
using System.Web;
using System.Web.Mvc;

namespace WebApplication1.Controllers
{
    public class LoginController : Controller
    {
        // GET: Login
        public ActionResult Index()
        {
            return View();
        }
        /// <summary>
        /// 验证码的校验
        /// </summary>
        /// <param name="context"></param>
        /// <returns></returns>
        public ActionResult CheckCode()
        {
            //生成验证码
            ValidateCode validateCode = new ValidateCode();
            string code = validateCode.CreateValidateCode(4);
            Session["ValidateCode"] = code;
            byte[] bytes = validateCode.CreateValidateGraphic(code);
            return File(bytes, @"image/jpeg");
        }
        /// <summary>
        /// 验证验证码是否正确
        /// </summary>
        /// <param name="num"></param>
        /// <returns></returns>
        public bool CheckValidateCode(string num)
        {

            string cnum = Session["ValidateCode"] == null ? "" : Session["ValidateCode"].ToString();

            if (num == cnum && !string.IsNullOrEmpty(num))
            {
                return true;
            }
            else
            {
                return false;
            }
        }
        /// <summary>
        /// 登录页面
        /// </summary>
        /// <returns></returns>
        public ActionResult Login()
        {
            return View();
        }
        /// <summary>
        /// 登录验证方法
        /// </summary>
        /// <param name="Info">info为存用户的实体,把用户信息与验证信息一起提交到这个方法里</param>
        /// <returns></returns>
        [HttpPost]
        public ActionResult Login(UserInfo Info)
        {
            ///Info.Str前段传入的验证字符串用CheckValidateCode()进行验证
            if (!CheckValidateCode(Info.Str))
            {
             return Content("<script>javascript:alert('验证码输入不正确');location.href='/Login/Login';</script>");
            }
            ///写个假的用户信息
            if (Info.UserName=="张三"&&Info.PassWord=="111")
            {
               return Content("<script>javascript:alert('登录成功');location.href='/Login/Index';</script>");
            }
            else
            {
                return Content("<script>javascript:alert('登录失败');location.href='/Login/Login';</script>");
            }          
        }

    }
}

前段MVC的写法

@{
    ViewBag.Title = "Login";
}

<h2>Login</h2>
<script>
    function ClickRemoveChangeCode() {
        var code = $("#imgCode").attr("src");
        $("#imgCode").attr("src", code + "1");
    }
</script>

@using (Html.BeginForm("Login", "Login", "post"))
{
    <table class="table active">
        <tr>
            <td>
                用户名
            </td>
            <td>
                <input type="text" name="UserName" value="" />
            </td>
        </tr>
        <tr>
            <td>
                密码
            </td>
            <td>
                <input type="text" name="PassWord" value="" />

            </td>
        </tr>
        <tr>
            <td>
                验证码
            </td>
            <td>
                <input type="text" name="Str" value="" />

            </td>
        </tr>
        <tr>
            <td>验证码：</td>

            <td>
                <img src="/Login/CheckCode?ID=1" id="imgCode" alt="单击可刷新" onclick="ClickRemoveChangeCode()" />
                <div style="float:right; margin-top: 5px;">
                    <a href="javascript:void(0)" onclick="ClickRemoveChangeCode();return false;">看不清，换一张</a>
                </div>
            </td>
        </tr>
        <tr>
            <td colspan="2">
                <input type="submit" value="登录" />
            </td>

        </tr>
    </table>
}