using System;

using Microsoft.Extensions.Caching.Memory;

using Microsoft.Extensions.DependencyInjection;

​

namespace MemoryCacheDemo

{

    class Program

    {

        static void Main(string[] args)

        {

            var services = new ServiceCollection();

            // can add global options like this but I don't think it's necessary when the whole process may share the cache

            // if no options just register as a singleton like services.AddMemoryCache(); https://github.com/aspnet/Caching/blob/9db2c381b19ff2aeb8d6783f145c3c41e1529b78/src/Microsoft.Extensions.Caching.Memory/MemoryCacheServiceCollectionExtensions.cs

            //var memoryCache = new MemoryCache(new MemoryCacheOptions 

            //{

                //SizeLimit = 50

            //});

            //services.AddSingleton<IMemoryCache>(memoryCache);

            services.AddMemoryCache();

            services.AddTransient<MyService>();

            var serviceProvider = services.BuildServiceProvider();

​

​

​

            var myService = serviceProvider.GetService<MyService>();

            myService.Add(1, "test");

            myService.Has(1); //should be found

            myService.Has(2); //should be not found

            var obj = myService.Get(1);

            Console.WriteLine(obj.ToString());

        }

    }

    public class MyService

    {

        private readonly IMemoryCache _memoryCache;

​

        public MyService(IMemoryCache memoryCache)

        {

            _memoryCache = memoryCache;

        }

​

        public void Add(int id, object obj)

        {

            _memoryCache.Set(id, new {Id = id, Obj = obj}, new MemoryCacheEntryOptions

            {

                // add your sliding expiration at the time of setting

                SlidingExpiration = TimeSpan.FromMinutes(2)

            });

            Console.WriteLine($"Added id {id} to cache");

        }

​

        public bool Has(int id)

        {

            var hasValue = _memoryCache.TryGetValue(id, out _);

            Console.WriteLine(hasValue ? $"Found {id} in cache" : $"Id {id} not found");

            return hasValue;

        }

​

        public object Get(int id)

        {

            _memoryCache.TryGetValue(id, out object obj);

            return obj;

        }

    }

}

​