图片验证码生成

        /// <summary>

        /// 自动生成图片验证码

        /// </summary>

        /// <param name="checkCode">返回的图片验证码</param>

        /// <param name="width">显示到客户端的图片宽度</param>

        /// <param name="height">显示到客户端的图片高度</param>

        /// <param name="checkCodeLength">验证码长度</param>

        /// <returns>流Stream返回</returns>

        public static byte[] CreateImgVidCode(ref string checkCode, int width = 124, int height = 40, int checkCodeLength = 5)

        {

            var rnd = new Random();

            char[] character = { '2', '3', '4', '5', '6', '8', '9', 'a', 'b', 'c', 'd', 'e', 'f', 'g', 'h', 'k', 'm', 'p', 'q', 'w', 'r', 's', 't', 'v', 'x', 'y', 'A', 'B', 'C', 'D', 'E', 'F', 'G', 'H', 'J', 'K', 'L', 'M', 'N', 'P', 'R', 'S', 'T', 'W', 'X',
'Y' };

            checkCode = string.Empty;

            var checkCodeFontSize = 16;

            for (int i = 0; i < checkCodeLength; i++)

            {

                checkCode += character[rnd.Next(character.Length)];

            }

            using (Bitmap image = new Bitmap(width, height))

            using (Graphics graphic = Graphics.FromImage(image))

            {

                Random random = new Random();

                graphic.Clear(Color.White);

                int x1 = 0, y1 = 0, x2 = 0, y2 = 0;

                for (int index = 0; index < 25; index++)

                {

                    x1 = random.Next(image.Width);

                    x2 = random.Next(image.Width);

                    y1 = random.Next(image.Height);

                    y2 = random.Next(image.Height);

                    graphic.DrawLine(new Pen(Color.Silver), x1, y1, x2, y2);

                }

                StringFormat stringFormat = new StringFormat();

                stringFormat.LineAlignment = StringAlignment.Center;

                stringFormat.Alignment = StringAlignment.Center;

                Rectangle lbRect = new Rectangle((width - 16 * checkCodeLength) / 6, (height - checkCodeFontSize) / 6, width, height);

                Font font = new Font("Arial", checkCodeFontSize, (FontStyle.Bold | FontStyle.Italic));

                LinearGradientBrush brush = new LinearGradientBrush(new Rectangle(0, 0, image.Width, image.Height), Color.Red, Color.DarkRed, 1.2f, true);

                graphic.DrawString(checkCode, font, brush, lbRect, stringFormat);

                int x = 0;

                int y = 0;

                for (int i = 0; i < 100; i++)

                {

                    x = random.Next(image.Width);

                    y = random.Next(image.Height);

                    image.SetPixel(x, y, Color.FromArgb(random.Next()));

                }

                graphic.DrawRectangle(new Pen(Color.Silver), 0, 0, image.Width - 1, image.Height - 1);

                using (var ms = new System.IO.MemoryStream())

                {

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

                    return ms.ToArray();

                }

            }
        }

===========================

=======html

                    <div class="n-input-box list-input2">

                        <label class="verification">

                            <i></i>

                            <input name="ImgVidCode" id="ImgVidCode" type="text" placeholder="请输入图形验证码" />

                        </label>

                        <img src="@Url.Action("CreateImgVidCode", "MemMember", new { vt = "R" })" width="124" height="40" alt="" onclick="this.src = this.src + '?'" style="cursor:pointer">

                        @*<p class="error" id="ImgCodeErrMsg"></p>*@

                        @Html.Raw("<p class='error' id='ImgCodeErrMsg'>" + System.Web.HttpUtility.HtmlDecode(Html.ValidationMessage("ImgCodeErrMsg", new { @class = "error" }).ToString()) + "</p>")

                    </div>

====controller

        /// 功能：图片验证码(5分钟内有效)

        /// </summary>

        /// <param name="vt">类型：L:登录；R:注册；S:设置交易密码；F:找回密码；B:绑定新手机</param>

        /// <returns></returns>

        public FileResult CreateImgVidCode(string vt = "L")

        {

            //验证码

            var code = string.Empty;

            //压力测试

            //var code = "666666";

            //对应的键

            var cacheKey = string.Empty;

            vt = vt.ToUpper().Replace("?", "");

            switch (vt)

            {

                default:

                case "L":

                    cacheKey = base.LoginImgVidCodeCacheKey;

                    break;

                case "R":

                    cacheKey = base.RegisterImgVidCodeCacheKey;

                    break;

                case "F":

                    cacheKey = base.FindPwdImgVidCodeCacheKey;

                    break;

                case "S":

                    cacheKey = base.SetPayPassWordMsgVidCodeCacheKey;

                    break;

                case "B":

                    cacheKey = base.BindingNewPhoneCacheKey;

                    break;

            }

            //取6位验证码或者5位

            var s = vt.Equals("L") || vt.Equals("F") || vt.Equals("S") || vt.Equals("B") ? CodeHelpers.CreateImgVidCode(ref code, checkCodeLength: 6) : CodeHelpers.CreateImgVidCode(ref code);

            //压力测试

            //var s = ClientHelper.CreateImgVidCode(code);

            //缓存验证码

            //HK.CM.Web.Utility.Common.CacheHelpers.set

            HKSJ.Common.DataCache.SetCache(cacheKey, code, DateTime.Now.AddMinutes(5), TimeSpan.Zero);

            return File(s, "image/Jpeg");

        }