LotNamesCache.cs

public class LotNamesCache : ILotNamesCache
{
    public const string CacheKey = nameof(LotNamesCache);
    private readonly ImmutableCacheDbContext _dbContext;
    private readonly IMemoryCache _cache;

    public LotNamesCache(ImmutableCacheDbContext dbContext, IMemoryCache cache)
    {
        _dbContext = dbContext;
        _cache = cache;
    }

    public async Task<ImmutableDictionary<string, string>> LotNamesDictionary()
    {
        if (!_cache.TryGetValue(CacheKey, out ImmutableDictionary<string, string> result))
        {
            var lotNames = await _dbContext.ParkingLots.AsNoTracking().ToListAsync();
            result = lotNames.ToImmutableDictionary(x => x.LotCode, x => x.LotName);
            var options = new MemoryCacheEntryOptions().SetSlidingExpiration(TimeSpan.FromDays(1));
            _cache.Set(CacheKey, result, options);
        }

        return result;
    }

    public void RemoveCachedDictionary()
    {
        _cache.Remove(CacheKey);
    }
}