Generic Cache Helper

I have written a generic Cache Helper which adds new methods to any object of type T which will add the object to either the global (application) or user (session) cache. It uses the HttpContext.Current.Cache underneath.

Example on how to use the class:

public MyType GetMyObject()
{
     MyType myObject;
     if(CacheHelper.TryGetFromCache(“key”, out myObject))
     {
          return myObject;
     }
     //fetch/create a new object, then cache it and return it
     myObject = CreateNewMyObject();
     myObject.AddToApplicationCache(“key”);
     return myObject;
}

Here’s the code for the Cache Helper:

public static class CacheHelper
{
    public static void AddToSessionCache<T>(this T item, string key) where T : class
    {

        HttpContext.Current.Session.Add(key, item);
    }

    public static void AddToApplicationCache<T>(this T item, string key) where T : class
    {
        AddToApplicationCache(item, key, Cache.NoSlidingExpiration, null);
    }

     public static void AddToApplicationCache<T>(this T item, string key, TimeSpan slidingExpiration) where T : class
    {
        AddToApplicationCache(item, key, slidingExpiration, null);
    }    

    public static void AddToApplicationCache<T>(this T item, string key, TimeSpan slidingExpiration, CacheDependency dependency) where T : class
     {
         HttpContext.Current.Cache.Add(key, item, null, Cache.NoAbsoluteExpiration, slidingExpiration, CacheItemPriority.Normal, null);
     }

     public static bool TryGetFromCache<T>(string key, out T item) where T : class
     {
         if (HttpContext.Current.Session[key] != null)
         {
             item = HttpContext.Current.Session[key] as T;
             return true;
         }
         if (HttpContext.Current.Cache[key] != null)
         {
             item = HttpContext.Current.Cache[key] as T;
             return true;
         }
         item = null;
         return false;
     }
}

Please use as you will, and at your own risk.