/// <summary>

        /// 获取验证码

        /// </summary>

        /// <returns></returns>

        [AllowAnonymous]

        public FileResult VerificationCode()

        {

            return File(this.CreateCheckCodeImage(GenerateCheckCode()).ToArray(), "image/Gif");

        }

        private string GenerateCheckCode()

        {

            int number;

            char code;

            string checkCode = String.Empty;

            System.Random random = new Random();

            for (int i = 0; i < 5; i++)

            {

                number = random.Next();

                if (number % 2 == 0)

                    code = (char)('0' + (char)(number % 10));

                else

                    code = (char)('A' + (char)(number % 26));

                if (code == '0')

                    code = 'M';

                checkCode += code.ToString();

            }

            Session["CheckCode"] = checkCode;

            return checkCode;

        }

        private MemoryStream CreateCheckCodeImage(string checkCode)

        {

            if (checkCode == null || checkCode.Trim() == String.Empty)

                return null;

            System.Drawing.Bitmap image = new System.Drawing.Bitmap((int)Math.Ceiling((checkCode.Length * 26.5)), 30);

            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);

                //画图片的背景噪音线

                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.ForestGreen), x1, y1, x2, y2);

                }

                Font font = new System.Drawing.Font("Tahoma", 20, (System.Drawing.FontStyle.Bold | System.Drawing.FontStyle.Italic));

                System.Drawing.Drawing2D.LinearGradientBrush brush = new System.Drawing.Drawing2D.LinearGradientBrush(new Rectangle(0, 0, image.Width, image.Height), Color.ForestGreen, Color.DarkRed, 1.2f, true);

                g.DrawString(checkCode, font, brush, -5, -5);

                //画图片的前景噪音点

                for (int i = 0; i < 80; i++)

                {

                    int x = random.Next(image.Width);

                    int y = random.Next(image.Height);

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

                }

                System.IO.MemoryStream ms = new System.IO.MemoryStream();

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

                return ms;

            }

            finally

            {

                g.Dispose();

                image.Dispose();

            }

        }

        /// <summary>

        /// 验证 验证码是否正确

        /// </summary>

        /// <param name="Code"></param>

        /// <returns></returns>

        private bool CheckCode(string Code)

        {

            if (HttpContext.Current.Session["CheckCode"] == null)

            {

                HttpContext.Current.Session.Remove("CheckCode");

                return false;

            }

            if (HttpContext.Current.Session["CheckCode"].ToString().Equals(Code, StringComparison.CurrentCultureIgnoreCase) == false)

            {

                HttpContext.Current.Session.Remove("CheckCode");

                return false;

            }

            HttpContext.Current.Session.Remove("CheckCode");

            return true;

        }

    public class CacheHelp

    {

        /// <summary>

        /// 缓存指定对象，设置缓存

        /// </summary>

        /// <param name="key">缓存的key</param>

        /// <param name="value">缓存的值</param>

        /// <param name="Seconds">设置缓存时间；单位：秒</param>

        /// <returns></returns>

        public static bool Set(string key, object value, double Seconds)

        {

            return Set(key, value, null, DateTime.Now.AddSeconds(Seconds), Cache.NoSlidingExpiration,

            CacheItemPriority.Default, null);

        }

        /// <summary>

        /// 缓存指定对象，设置缓存

        /// </summary>

        public static bool Set(string key, object value, string path)

        {

            try

            {

                var cacheDependency = new CacheDependency(path);

                return Set(key, value, cacheDependency);

            }

            catch

            {

                return false;

            }

        }

        /// <summary>

        /// 缓存指定对象，设置缓存

        /// </summary>

        public static bool Set(string key, object value, CacheDependency cacheDependency)

        {

            return Set(key, value, cacheDependency, Cache.NoAbsoluteExpiration, Cache.NoSlidingExpiration,

            CacheItemPriority.Default, null);

        }

        /// <summary>

        /// 缓存指定对象，设置缓存

        /// </summary>

        public static bool Set(string key, object value, double seconds, bool isAbsulute)

        {

            return Set(key, value, null, (isAbsulute ? DateTime.Now.AddSeconds(seconds) : Cache.NoAbsoluteExpiration),

            (isAbsulute ? Cache.NoSlidingExpiration : TimeSpan.FromSeconds(seconds)), CacheItemPriority.Default,

            null);

        }

        /// <summary>

        /// 获取缓存对象

        /// </summary>

        public static object Get(string key)

        {

            return GetPrivate(key);

        }

        /// <summary>

        /// 判断缓存中是否含有缓存该键

        /// </summary>

        public static bool Exists(string key)

        {

            return (GetPrivate(key) != null);

        }

        /// <summary>

        /// 移除缓存对象

        /// </summary>

        /// <param name="key"></param>

        /// <returns></returns>

        public static bool Remove(string key)

        {

            if (string.IsNullOrEmpty(key))

            {

                return false;

            }

            HttpRuntime.Cache.Remove(key);

            return true;

        }

        /// <summary>

        /// 移除所有缓存

        /// </summary>

        /// <returns></returns>

        public static bool RemoveAll()

        {

            IDictionaryEnumerator iDictionaryEnumerator = HttpRuntime.Cache.GetEnumerator();

            while (iDictionaryEnumerator.MoveNext())

            {

                HttpRuntime.Cache.Remove(Convert.ToString(iDictionaryEnumerator.Key));

            }

            return true;

        }

        /// <summary>

        /// 尝试获取缓存，不存在则执行匿名委托

        /// </summary>

        /// <typeparam name="T"></typeparam>

        /// <param name="key"></param>

        /// <param name="func"></param>

        /// <param name="Seconds">设置缓存时间；单位：秒</param>

        /// <returns></returns>

        public static T TryGet<T>(string key, Func<T> func, double Seconds)

        {

            if (Exists(key)) return (T)Get(key);

            var result = func.Invoke();

            Set(key, result, Seconds);

            return result;

        }

        /// <summary>

        /// 设置缓存

        /// </summary>

        public static bool Set(string key, object value, CacheDependency cacheDependency, DateTime dateTime,

        TimeSpan timeSpan, CacheItemPriority cacheItemPriority, CacheItemRemovedCallback cacheItemRemovedCallback)

        {

            if (string.IsNullOrEmpty(key) || value == null)

            {

                return false;

            }

            HttpRuntime.Cache.Insert(key, value, cacheDependency, dateTime, timeSpan, cacheItemPriority,

            cacheItemRemovedCallback);

            return true;

        }

        /// <summary>

        /// 获取缓存

        /// </summary>

        private static object GetPrivate(string key)

        {

            return string.IsNullOrEmpty(key) ? null : HttpRuntime.Cache.Get(key);

        }

    }