Getting/Adding/Updating/Inserting Into Cache

This section describes how you should be getting/adding/updating/inserting items in the cache.

Adding and retrieving items in the cache

The recommended way to put data in and get data out is to use one of the many overloaded methods of: GetCacheItem. The GetCacheItem methods (all except one) are designed to "Get or Add" to the cache. The following retrieves an item from the cache and adds it if it doesn't already exist:

MyObject cachedItem = _appCaches.RuntimeCache.GetCacheItem<MyObject>("MyCacheKey", () => new MyObject());

where _appCaches is injected as type AppCaches.

Notice 2 things:

• The GetCacheItem method is strongly typed and

• We are supplying a callback method which is used to populate the cache if it doesn't exist.

The example above will retrieve a strongly typed object of MyObject from the cache with the key of "MyCacheKey". If the object doesn't exist in the cache, a new instance of MyObject MyObject be added to it with the same key.

There are a couple of overloads of GetCacheItem allowing you to customize how your object is cached from cache dependencies to expiration times.

To use this generic implementation, add the Umbraco.Extensions namespace to your code.

Retrieving an item from the cache without a callback

One of the overloads of GetCacheItem doesn't specify a callback. This allows you to retrieve an item from the cache without populating it if it doesn't exist.

An example of usage:

MyObject cachedItem = _appCaches.RuntimeCache.GetCacheItem<MyObject>("MyCacheKey");

where _appCaches is injected as type AppCaches.

Inserting an item into the cache without retrieval

Sometimes you might want to put something in the cache without retrieving it. In this case there is an InsertCacheItem<T> method. This method will add or update the cache item specified by the key. If the item already exists in the cache, it will be replaced.