TimedCacheValue - Simple C# class which acts like Lazy<T> but only keeps the value for a specified amount of time.

TimeCachedValue.cs

using System;
using System.Runtime.Caching;

namespace SampleApp.Support
{
    public class TimeCachedValue<T>
    {
        private readonly Func<T> valueFactory;
        private readonly TimeSpan objectLifeSpan;

        MemoryCache cache = MemoryCache.Default;
        private string cacheIdentifierKey = Guid.NewGuid().ToString();

        public TimeCachedValue(Func<T> valueFactory, TimeSpan expireTime)
        {
            this.valueFactory = valueFactory;
            this.objectLifeSpan = expireTime;
        }

        public T Value {
            get {
                if (this.cache.Get(this.cacheIdentifierKey) == null)
                {
                    // get a new value from the supplied factory function, and store it in the cache
                    T value = this.valueFactory.Invoke();
                    // set up a cache policy...
                    var cacheItemPolicy = new CacheItemPolicy() { AbsoluteExpiration = DateTimeOffset.Now.Add(this.objectLifeSpan) };
                    // put it in the cache
                    this.cache.Set(this.cacheIdentifierKey, value, cacheItemPolicy);
                }

                // return the value from the in-memory cache
                T returnValue = (T)this.cache.Get(this.cacheIdentifierKey);
                return returnValue;
            }
        }

    }
}