publicclass ActionOutputCacheAttribute : ActionFilterAttribute     {         privatestatic MethodInfo _switchWriterMethod =typeof(HttpResponse).GetMethod("SwitchWriter", BindingFlags.Instance | BindingFlags.NonPublic);         public ActionOutputCacheAttribute(int cacheDuration)         {             _cacheDuration = cacheDuration;         }         //目前还不能设置为Client缓存，会与OutputCache同样的问题         private CachePolicy _cachePolicy = CachePolicy.Server;         privateint _cacheDuration;         private TextWriter _originalWriter;         privatestring _cacheKey;         publicoverridevoid OnActionExecuting(ActionExecutingContext filterContext)         {             // Server-side caching?             if (_cachePolicy == CachePolicy.Server || _cachePolicy == CachePolicy.ClientAndServer)             {                 _cacheKey = GenerateCacheKey(filterContext);                 CacheContainer cachedOutput = (CacheContainer)filterContext.HttpContext.Cache[_cacheKey];                 if (cachedOutput !=null)                 {                     filterContext.HttpContext.Response.ContentType = cachedOutput.ContentType;                     filterContext.Result =new ContentResult { Content = cachedOutput.Output };                 }                 else                 {                     StringWriter stringWriter =new StringWriterWithEncoding(filterContext.HttpContext.Response.ContentEncoding);                     HtmlTextWriter newWriter =new HtmlTextWriter(stringWriter);                     _originalWriter = (TextWriter)_switchWriterMethod.Invoke(HttpContext.Current.Response, newobject[] { newWriter });                 }             }         }         publicoverridevoid OnResultExecuted(ResultExecutedContext filterContext)         {             // Server-side caching?             if (_cachePolicy == CachePolicy.Server || _cachePolicy == CachePolicy.ClientAndServer)             {                 if (_originalWriter !=null) // Must complete the caching                 {                     HtmlTextWriter cacheWriter = (HtmlTextWriter)_switchWriterMethod.Invoke(HttpContext.Current.Response, newobject[] { _originalWriter });                     string textWritten = ((StringWriter)cacheWriter.InnerWriter).ToString();                     filterContext.HttpContext.Response.Write(textWritten);                     CacheContainer container =new CacheContainer(textWritten, filterContext.HttpContext.Response.ContentType);                     filterContext.HttpContext.Cache.Add(_cacheKey, container, null, DateTime.Now.AddSeconds(_cacheDuration), System.Web.Caching.Cache.NoSlidingExpiration, System.Web.Caching.CacheItemPriority.Normal, null);                 }             }         }         privatestring GenerateCacheKey(ActionExecutingContext filterContext)         {             StringBuilder cacheKey =new StringBuilder("OutputCacheKey:");             // Controller + action             cacheKey.Append(filterContext.Controller.GetType().FullName.GetHashCode());             if (filterContext.RouteData.Values.ContainsKey("action"))             {                 cacheKey.Append("_");                 cacheKey.Append(filterContext.RouteData.Values["action"].ToString());             }             foreach (KeyValuePair<string, object> pair in filterContext.ActionParameters)             {                 cacheKey.Append("_");                 cacheKey.Append(pair.Key);                 cacheKey.Append("=");                 if (pair.Value !=null)                     cacheKey.Append(pair.Value.ToString());                 else                     cacheKey.Append(string.Empty);             }             return cacheKey.ToString();         }         privateclass CacheContainer         {             publicstring Output;             publicstring ContentType;             public CacheContainer(string data, string contentType)             {                 Output = data;                 ContentType = contentType;             }         }         publicenum CachePolicy         {             NoCache =0,             Client =1,             Server =2,             ClientAndServer =3         }     }

StringWriterWithEncoding     publicclass StringWriterWithEncoding : StringWriter     {         Encoding encoding;         public StringWriterWithEncoding(Encoding encoding)         {             this.encoding = encoding;         }         publicoverride Encoding Encoding         {             get{ return encoding; }         }     }