ObjectCache cache = MemoryCache.Default;            //1            string cacheData1 = cache["key1"] as string;//得不到数据            //2            //string cacheData1 = Convert.ToString(cache["key1"]);//这个ok            CacheItemPolicy policy1 = new CacheItemPolicy();            policy1.AbsoluteExpiration = new DateTimeOffset(DateTime.Now.AddMinutes(30));            cache.Set("key1", 10, policy1);                        Response.Write($"
{cacheData1}
");            Response.End();