简单使用Enterprise Library 5.0 中的Cache功能

1. 首先使用Configuration Console, 在blocks里面 Add Caching Setteings. 设置一些参数，比如Expiration Polling Frequency(seconds), 这个是指每隔指定的时间，cache block会检查那些过期的cache item，并且把他们删除掉。

2. 配置好以后可以保存为一个config文件，然后把config内容拷贝到你的project中的配置文件中。

  <configSections>
    <section name="cachingConfiguration" type="Microsoft.Practices.EnterpriseLibrary.Caching.Configuration.CacheManagerSettings, Microsoft.Practices.EnterpriseLibrary.Caching, Version=5.0.414.0, Culture=neutral, PublicKeyToken=31bf3856ad364e35" requirePermission="true" />
  </configSections>
  <cachingConfiguration defaultCacheManager="Data Cache Manager">
    <cacheManagers>
      <add name="Data Cache Manager" type="Microsoft.Practices.EnterpriseLibrary.Caching.CacheManager, Microsoft.Practices.EnterpriseLibrary.Caching, Version=5.0.414.0, Culture=neutral, PublicKeyToken=31bf3856ad364e35"
          expirationPollFrequencyInSeconds="3600" maximumElementsInCacheBeforeScavenging="1000"
          numberToRemoveWhenScavenging="10" backingStoreName="NullBackingStore" />
    </cacheManagers>
    <backingStores>
      <add type="Microsoft.Practices.EnterpriseLibrary.Caching.BackingStoreImplementations.NullBackingStore, Microsoft.Practices.EnterpriseLibrary.Caching, Version=5.0.414.0, Culture=neutral, PublicKeyToken=31bf3856ad364e35"
          name="NullBackingStore" />
    </backingStores>
  </cachingConfiguration>

3. 在你的project中引入一些dll。

Microsoft.Practices.EnterpriseLibrary.Caching.dll
Microsoft.Practices.EnterpriseLibrary.Caching.Cryptography.dll
Microsoft.Practices.EnterpriseLibrary.Caching.Database.dll
Microsoft.Practices.EnterpriseLibrary.Data.dll
Microsoft.Practices.EnterpriseLibrary.Security.Cryptography.dll

4. 现在就可以使用cache了，下面的是一个简单的使用cache功能的方法。

 private Instance GetInstanceCache(string guid)
        {
            Instance ins = null;
            string key = "INS" + guid;
            ICacheManager defaultCache = EnterpriseLibraryContainer.Current.GetInstance<ICacheManager>();
            if (defaultCache.Contains(key))
            {
                object cache = defaultCache.GetData(key);
                if (cache != null)
                {
                    ins = cache as Instance;
                }
                else
                {
                    ins = BLInstance.GetInstanceByGuid(guid);
                    defaultCache.Remove(key);
                    defaultCache.Add(key, ins, CacheItemPriority.High, null, new SlidingTime(new TimeSpan(int.Parse(ConfigurationManager.AppSettings["ExpirationTimeHours"]), int.Parse(ConfigurationManager.AppSettings["ExpirationTimeMinutes"]), int.Parse(ConfigurationManager.AppSettings["ExpirationTimeSeconds"]))));
                }
            }
            else
            {
                ins = BLInstance.GetInstanceByGuid(guid);
                defaultCache.Add(key, ins, CacheItemPriority.High, null, new SlidingTime(new TimeSpan(int.Parse(ConfigurationManager.AppSettings["ExpirationTimeHours"]), int.Parse(ConfigurationManager.AppSettings["ExpirationTimeMinutes"]), int.Parse(ConfigurationManager.AppSettings["ExpirationTimeSeconds"]))));
            }

            return ins;
        }