Enterprise Library 3.1 - Caching Application Block (Part 2)

The previous article in this series explained about the features and architecture of the Caching application Block. In this series we will try to implement the Application Block.

Using the Caching Application Block

1. Add Enterprise Library 3.1 references to the project.
• Microsoft.Practices.EnterpriseLibrary.Caching.dll
• Microsoft.Practices.EnterpriseLibrary.Common.dll
• Microsoft.Practices.ObjectBuilder.dll
2. Right click the App.config file and select Edit Enterprise Library Configuration
3. Right click the Project in the Enterprise Library Configuration console and select New -->Caching Application Block

4. Create a backing store by right-clicking the Cache Manager node and select

New -->Isolated Storage.
5. Select the PartitionName property and name it MyCachePartition

6. Save and close the Configuration Console
7. Implement the ICacheItemRefreshAction

The ICacheItemRefreshAction interface refreshes the CacheManager instance when it is expired, preventing the occurrence of a Null Reference exception.

[Serializable]
public class CacheRefreshPolicy : ICacheItemRefreshAction
{
#region ICacheItemRefreshAction Members

public void Refresh(string removedKey, object expiredValue, CacheItemRemovedReason removalReason)
{
CacheManager _myCacheManager = CacheFactory.GetCacheManager();
_myCacheManager.Add(removedKey, "Item removed on " + DateTime.Today.ToLongDateString());
}

#endregion
}

8. Adding into the cache

CacheManager _myCacheManager = CacheFactory.GetCacheManager();

_myCacheManager.Add("MyCacheKey", CacheContentTextBox.Text,
CacheItemPriority.Normal, new CacheRefreshPolicy(),
new SlidingTime(TimeSpan.FromSeconds(60)));

9. Retrieving data from the cache

CacheManager _myCacheManager = CacheFactory.GetCacheManager();
if (_myCacheManager != null)
{
if (_myCacheManager.Contains("MyCacheKey"))
{
CacheContentLabel.Text = _myCacheManager.GetData("MyCacheKey") as String;
}
else
{
CacheContentLabel.Text = "Cache is missing!!!";
}
}
else
{
CacheContentLabel.Text = "Cache Manager is not present!!!";
}

10. Removing data from the cache

CacheManager _ myCacheManager = CacheFactory.GetCacheManager();
_ myCacheManager.Remove("MyCacheKey");