问如何在_Layout中访问会话而不必担心它已过期

EN

public interface IUserRepository
{
    string GetUserTheme(int userId);
    void SetUserTheme(int userId, string theme);
}

public class CachedUserRepository : IUserRepository
{
    private readonly IMemoryCache cache;
    private readonly IUserRepository userRepository;
    // Cache Expire duration
    private static TimeSpan CacheDuration = TimeSpan.FromMinutes(5);

    public CachedUserRepository(IUserRepository userRepository, IMemoryCache memoryCache)
    {
        if (userRepository == null)
            throw new ArgumentNullException(nameof(userRepository));

        if (memoryCache == null)
            throw new ArgumentNullException(nameof(memoryCache));

        this.userRepository = userRepository;
        this.cache = memoryCache;
    }

    public string GetUserTheme(int userId)
    {
        string theme;

        // adding a prefix to make the key unique
        if (cache.TryGetValue($"usertheme-{userId}", out theme))
        {
            // found in cache
            return theme;
        };

        // fetch from database
        theme = userRepository.GetUserTheme(userId);

        // put it into the cache, expires in 5 minutes
        cache.Set($"usertheme-{userId}", theme, new MemoryCacheEntryOptions { AbsoluteExpirationRelativeToNow = CacheDuration });

        return theme;
    }

    public void SetUserTheme(int userId, string theme)
    {
        // persist it
        userRepository.SetUserTheme(userId, theme);


        // put it into the cache, expires in 5 minutes
        cache.Set($"usertheme-{userId}", theme, new MemoryCacheEntryOptions { AbsoluteExpirationRelativeToNow = CacheDuration });
    }
}

    services.AddScoped<IUserRepository>(container => {
        return new CachedUserRepository(container.GetService<UserRepository>(), container.GetServices<IMemoryCache>());
    });

userManager.AddClaimAsync(user, new Claim("Template", id+""));
signInManager.SignInAsync(user);