MemoryCache expiration value .NET

Question

I'm trying to cache some values and my goal is to keep them until they get overwritten. So basically they should never expire.

var memoryCache = MemoryCache.Default;

if (!memoryCache.Contains("data"))
{
    var timer = DateTimeOffset.UtcNow.AddMinutes(1);
    var data = jsonContent;

    memoryCache.Add("data", data, timer);
}

How can I work around the expiration parameter? I've read something about the CacheItemPolicy but I didn't understand it.

Thanks for any help in advance.

Answer 1

Looking at the documentation it seems that you can set theSlidingExpiration property on the CacheItemPolicy object to NoSlidingExpiration which seems to indicate that it will not expire, see here

A cache entry that is inserted into the cache with the NoSlidingExpiration field value set as the expiration value should never be evicted because of non-activity in a sliding time window.

So you can do something like the following:

memoryCache.Add(new CacheItem("data", data), new CacheItemPolicy
{
    SlidingExpiration = System.Runtime.Caching.NoSlidingExpiration
});

Please note the code above might not compile, it's just an example on how to use it.