Question

I am using Enterprise Library Caching block without configuration file. Cache settings are initialized from my code. I initialize the cache with the following code:

static class LocalCache
    {
        private static readonly CacheManager CacheManager;

        static LocalCache()
        {
            try
            {
                string localCacheName = "MyCache";

                DictionaryConfigurationSource configSource = new DictionaryConfigurationSource();
                CacheManagerSettings cacheSettings = new CacheManagerSettings();

                configSource.Add(CacheManagerSettings.SectionName, cacheSettings);
                CacheStorageData storageConfig = new CacheStorageData("NoStorage", typeof(NullBackingStore));
                cacheSettings.BackingStores.Add(storageConfig);

                var expirationPollFrequencyInSeconds = 2;
                CacheManagerData cacheManagerData = new CacheManagerData(
                    localCacheName, 
                    expirationPollFrequencyInSeconds, 
                    100, 
                    20, 
                    storageConfig.Name
                    );
                cacheSettings.CacheManagers.Add(cacheManagerData);
                cacheSettings.DefaultCacheManager = cacheManagerData.Name;

                CacheManagerFactory cacheFactory = new CacheManagerFactory(configSource);
                CacheManager = cacheFactory.CreateDefault();
            }
            catch (Exception e)
            {
                Console.WriteLine(e.Message);
            }
        }

        public static T GetData<T>(string cacheKey)
        {
            var value = CacheManager.GetData(cacheKey);
            return (T)value;
        }

        public static void AddData(string cacheKey, object value)
        {
            CacheManager.Add(cacheKey, value);                
        }
    }

The issue is that the expirationPollFrequencyInSeconds (here 2 seconds) is not taken into account when retrieving a cache item that is supposed to be expired. The item reside in cache longer than 2 seconds. Any idea ?

See test example below:

private static void Main(string[] args)
    {
        try
        {
            LocalCache.AddData("One", 1);
            Thread.Sleep(5000);
            LocalCache.AddData("Two", 2);

            object data = LocalCache.GetData<object>("One");

            if (data == null) Console.WriteLine("Data not in cache");
            else Console.WriteLine("-----> Data in cache whereas it should not !!!");
        }
        catch (Exception e)
        {
            Console.WriteLine(e.Message);
        }
    }

Output:

-----> Data in cache whereas it should not !!!

Answer 1

根据CacheManagerData类的在线文档，构造函数不会占用缓存专家持续时间。相反，第二个参数是经理将检查如果项目太多，是否要删除缓存项目的时间段。

因此，2秒不是缓存到期。

是否有太多项目取决于第三个参数。

https://msdn.microsoft.com/en-us/library/ee779632.aspx

如果您想添加有效期，请查看以下内容：

http://www.codeproject.com/Articles/51409/Exploring-Caching-Using-Caching-Application-Enterp#heading0016

Entreprise library caching configuration without configuration file

1 个答案: