C#生成简单验证码

我们平时无论是网站登录还是注册，都会频繁的遇到各式各样的验证码 ，其实生成验证码对于C#来说非常简单。

下面就是我学习生成验证码的简单实例。

封装的辅助类代码，如下：

using System;
using System.Collections.Generic;
using System.Drawing;
using System.Drawing.Drawing2D;
using System.Linq;
using System.Security.Cryptography;
using System.Text;
using System.Threading.Tasks;

namespace Ninesky.Common
{
    public class Security
    {
        /// <summary>
        /// 创建验证码字符
        /// 利用伪随机数生成器生成验证码字符串。
        /// </summary>
        /// <param name="length">字符长度</param>
        /// <returns>验证码字符</returns>
        public static string CreateVerificationText(int length)
        {
            char[] _verification = new char[length];
            char[] _dictionary = { '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', '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', '0', '1', '2', '3', '4', '5', '6', '7', '8', '9' };
            Random _random = new Random();
            for (int i = 0; i < length; i++)
            {
                _verification[i] = _dictionary[_random.Next(_dictionary.Length - 1)];
            }
            return new string(_verification);
        }
        /// <summary>
        /// 创建验证码图片
        /// 思路是使用GDI+创建画布，使用伪随机数生成器生成渐变画刷，然后创建渐变文字。
        /// </summary>
        /// <param name="verificationText">验证码字符串</param>
        /// <param name="width">图片宽度</param>
        /// <param name="height">图片长度</param>
        /// <returns>图片</returns>
        public static Bitmap CreateVerificationImage(string verificationText, int width, int height)
        {
            Pen _pen = new Pen(Color.Black);
            Font _font = new Font("Arial", 14, FontStyle.Bold);
            Brush _brush = null;
            Bitmap _bitmap = new Bitmap(width, height);
            Graphics _g = Graphics.FromImage(_bitmap);
            SizeF _totalSizeF = _g.MeasureString(verificationText, _font);
            SizeF _curCharSizeF;
            //PointF _startPointF = new PointF((width - _totalSizeF.Width) / 2, (height - _totalSizeF.Height) / 2);
            PointF _startPointF = new PointF(0, (height - _totalSizeF.Height) / 2);
            //随机数产生器
            Random _random = new Random();
            _g.Clear(Color.White);
            for (int i = 0; i < verificationText.Length; i++)
            {
                _brush = new LinearGradientBrush(new Point(0, 0), new Point(1, 1), Color.FromArgb(_random.Next(255), _random.Next(255), _random.Next(255)), Color.FromArgb(_random.Next(255), _random.Next(255), _random.Next(255)));
                _g.DrawString(verificationText[i].ToString(), _font, _brush, _startPointF);
                _curCharSizeF = _g.MeasureString(verificationText[i].ToString(), _font);
                _startPointF.X += _curCharSizeF.Width;
            }
            _g.Dispose();
            return _bitmap;
        }
        /// <summary>
        /// 256位散列加密
        /// </summary>
        /// <param name="plainText">明文</param>
        /// <returns>密文</returns>
        public static string Sha256(string plainText)
        {
            SHA256Managed _sha256 = new SHA256Managed();
            byte[] _cipherText = _sha256.ComputeHash(Encoding.Default.GetBytes(plainText));
            return Convert.ToBase64String(_cipherText);
        }
    }
}

 后台控制器代码，如下：

using System;
using System.Collections.Generic;
using System.Drawing;
using System.Linq;
using System.Web;
using System.Web.Mvc;
using Ninesky.Common;

namespace WebTest.Controllers
{
    public class VerificationCodeController : Controller
    {
        List<string> userlist = new List<string>();
        //
        // GET: /VerificationCode/

        public ActionResult Index()
        {
            ViewData["VerificationCode"] = TempData["VerificationCode"];
            return View();
        }
        /// <summary>
        /// 验证码
        /// </summary>
        /// <returns></returns>
        public ActionResult VerificationCode()
        {
            string verificationCode = Security.CreateVerificationText(6);
            Bitmap _img = Security.CreateVerificationImage(verificationCode, 140, 30);
            _img.Save(Response.OutputStream, System.Drawing.Imaging.ImageFormat.Jpeg);
            TempData["VerificationCode"] = verificationCode.ToUpper();
            return null;
        }

        public string Register(FormCollection coll)
        {
            string AccountNumber = coll["AccountNumber"].Trim().ToString();
            string Password = coll["Password"].Trim().ToString();
            string ConfirmPassword = coll["ConfirmPassword"].Trim().ToString();
            string verificationcode = coll["verificationcode"].Trim().ToString().ToUpper();
            if (string.IsNullOrEmpty(AccountNumber))
            {
                return "用户名称不能为空！";
            }
            else if (userlist.Count > 0 && userlist.Where(m => m == AccountNumber).First() != null)
            {
                return "该用户已存在！";
            }
            else if (!Password.Equals(ConfirmPassword))
            {
                return "两次输入密码不一致！";
            }
            else if (!verificationcode.Equals(TempData["VerificationCode"].ToString()))
            {
                return "验证码输入错误！";
            }
            else
            {
                userlist.Add(AccountNumber);
                return "恭喜你，注册成功！";
            }
        }
    }
}

 前台页面代码，如下：

@{
    ViewBag.Title = "注册页面";
}
<script src="~/Scripts/jquery-3.1.1.min.js"></script>
<style type="text/css">
    .txt
    {
        height: 30px;
    }

    .td td
    {
        max-height: 15px;
        padding: 0px;
        margin: 0px;
    }

    .img
    {
        padding: 0px;
        margin: 0px;
    }
</style>
<script type="text/javascript">
    $(function () {
        $("#Agreest").change(function () {
            if ($("#Agreest").checked) {
                $("#btnRegister").attr({ "disabled": "disabled" });
                //$("#btnRegister").attr("disabled", true);
            } else {
                $("#btnRegister").removeAttr("disabled");
                //$("#btnRegister").attr("disabled", false);
            }
        })
        $("#btnRegister").click(function () {
            if ($("#Agreest").checked == false) {
                alert("请认真阅读用户注册协议！");
                return;
            }
            var vc = $("#verificationcode").val();
            $.ajax({
                type: "POST",
                url: "/VerificationCode/Register",
                data: $("#FormRegister").serialize(),
                success: function (data) {
                    alert(data);
                    $("#verificationcodeimg").attr("src", "@Url.Action("VerificationCode")?" + new Date());
                }
            });
        });
        $("#verificationcodeimg").click(function () {
            $("#verificationcodeimg").attr("src", "@Url.Action("VerificationCode")?" + new Date());
        });
    });

</script>
<form action="/VerificationCode/Register" method="post" id="FormRegister">
    <table class="td">
        <tr>
            <td></td>
            <td>用户注册</td>
            <td></td>
        </tr>
        <tr>
            <td>账号:</td>
            <td>
                <input type="text" class="txt" value="" name="AccountNumber" id="AccountNumber">
            </td>
            <td></td>
        </tr>
        <tr>
            <td>密码:</td>
            <td>
                <input type="text" class="txt" value="" name="Password" id="Password">
            </td>
            <td></td>
        </tr>
        <tr>
            <td>确认密码:</td>
            <td>
                <input type="text" class="txt" value="" name="ConfirmPassword" id="ConfirmPassword">
            </td>
            <td></td>
        </tr>
        <tr>
            <td>验证码:</td>
            <td>
                <input type="text" class="txt" value="" name="verificationcode" id="verificationcode">
            </td>
            <td>
                <img id="verificationcodeimg" class="img" title = "点击刷新" src = "@Url.Action("VerificationCode")" style="cursor:pointer"/></td>
        </tr>
        <tr>
            <td colspan="2">
                <input id="Agreest" type="checkbox" checked="checked" />我同意<a href="#">《用户注册协议》</a>
            </td>
            <td></td>
        </tr>
        <tr>
            <td></td>
            <td>
                <input type="button" value="注册" id="btnRegister" class="btn" />
            </td>
            <td></td>
        </tr>
    </table>
</form>

 实例效果图，如下：

作者：长毛象

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博客：http://www.cnblogs.com/xiangyisheng/

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