做了一个缓存文件依赖

        private string DependencyDirectory = System.Web.HttpContext.Current.Server.MapPath("~/FileCacheDependency");
        private string DependencyFile = System.Web.HttpContext.Current.Server.MapPath("~/FileCacheDependency") + "\\DependencyFile" ;
        private string AuthorizationCacheKey = "AuthorizationCacheKey";       

 
        public void UpdateDependency()
        {
            if (System.IO.File.Exists(DependencyFile))
            {
                FileInfo FI = new FileInfo(DependencyFile);
                StreamWriter SW = FI.AppendText();
                SW.WriteLine(Guid.NewGuid().ToString());
                SW.Close();
            }
        }

        private void CreateDependency()
        {
            if (!Directory.Exists(DependencyDirectory))
            {
                Directory.CreateDirectory(DependencyDirectory);
            }
            if (!File.Exists(DependencyFile))
            {
                FileStream fs = File.Create(DependencyFile);
                fs.Close();
            }
        }

        public void AddOperationAuthorization(Object Obj)
        {
            CreateDependency();
            CacheDependency CD = new CacheDependency(DependencyFile);
            CacheService.InsertCache(AuthorizationCacheKey, Obj, CD);
        }

 
        private static bool InsertCachePrivate(string CacheKey, object CacheInfo, CacheDependency CD, CacheItemRemovedCallback CallBack)
        {
            if (CacheKey != null && CacheKey.Length != 0 && CacheInfo != null)
            {

                HttpContext.Current.Cache.Insert(CacheKey, CacheInfo, CD,
                    System.DateTime.Now.AddSeconds(300),
                    System.Web.Caching.Cache.NoSlidingExpiration,
                    System.Web.Caching.CacheItemPriority.Default,
                    CallBack);
                return true;
            }
            else
            {
                return false;
            }
        }

        public static bool InsertCache(string CacheKey, object CacheInfo, CacheDependency CD)
        {
            CacheItemRemovedCallback CallBackPrivate = new CacheItemRemovedCallback(onRemove);
            return InsertCachePrivate(CacheKey, CacheInfo, CD, CallBackPrivate);
        }

        private static void onRemove(string IdentifyCode, object CacheInfo, CacheItemRemovedReason reason)
        {

        }