MemoryCache Helper

CacheHelper.cs

using System;
using System.Collections.Generic;
using System.Linq;
using System.Runtime.Caching;
using System.Text;
using System.Threading.Tasks;

namespace TestProj.Helpers
{
    /// <summary>
    /// Helpers on top of System.Runtime.Caching.MemoryCache.Default.
    /// </summary>
    public static class CacheHelper
    {
        /// <summary>
        /// Get or Add an object of a given type to MemoryCache.Default. Uses AbsoluteExpiration as CacheItemPolicy.
        /// </summary>
        /// <typeparam name="T"></typeparam>
        /// <param name="cacheItemName"></param>
        /// <param name="cacheTimeInMinutes"></param>
        /// <param name="objectSettingFunction"></param>
        /// <returns></returns>
        public static T GetOrAddObject<T>(string cacheItemName, int cacheTimeInMinutes, Func<T> objectSettingFunction)
        {
            var cache = MemoryCache.Default;
            var cachedObject = (T)cache[cacheItemName];
            if (cachedObject == null)
            {
                var policy =
                    new CacheItemPolicy { AbsoluteExpiration = DateTimeOffset.Now.AddMinutes(cacheTimeInMinutes) };
                cachedObject = objectSettingFunction();
                cache.Set(cacheItemName, cachedObject, policy);
            }
            return cachedObject;
        }

        /// <summary>
        /// Check if a given item exists in MemoryCache.Default; Remove it.
        /// </summary>
        /// <param name="cachedItemName"></param>
        public static void RemoveCachedItem(string cachedItemName)
        {
            var cache = MemoryCache.Default;
            var cachedObject = cache[cachedItemName];

            if (cachedObject != null)
            {
                cache.Remove(cachedItemName);
            }
        }

        /// <summary>
        /// Grab all keys in MemoryCache.Default, and remove them one by one.
        /// </summary>
        public static void ClearAllCachedItems()
        {
            var cachedKeys = MemoryCache.Default.Select(c => c.Key).ToList();
            foreach (var cacheKey in cachedKeys)
            {
                MemoryCache.Default.Remove(cacheKey);
            }
        }
    }
}

Example.cs

using TestProj.Helpers

namespace TestProj
{
    public class CustomStuff() 
    {
        public SomeCustomObject GetCustomObjectFromCache() 
        {
            var custObj = CacheHelper.GetOrAddObject("someUniqueItemIdentifier", cacheTimeInMinutes: 1440, () => 
            {
                // Some expensive call to get SomeCustomObject
                var obj = ExpensiveCall();

                return obj;
            });
            return custObj.
        }
    }
}