在.NET Core中提供了Caching的组件。目前Caching组件提供了三种存储方式：
新建一个ASP.NET Core Web应用程序项目，然后安装 Microsoft.Extensions.Caching.Memory。
修改ConfigureServices方法
services.AddMemoryCache(); services.AddMvc().SetCompatibilityVersion(CompatibilityVersion.Version_2_1);
在HomeController使用：
private IMemoryCache memoryCache;
public HomeController( IMemoryCache _memoryCache)
{
memoryCache = _memoryCache;
}
public IActionResult Index()
{
string cacheKey = "key";
string result;
if (!memoryCache.TryGetValue(cacheKey, out result))
{
result = $"LineZero{DateTime.Now}";
memoryCache.Set(cacheKey, result);
//设置相对过期时间
memoryCache.Set(cacheKey, result, new MemoryCacheEntryOptions()
.SetSlidingExpiration(TimeSpan.FromSeconds(10)));
//设置绝对过期时间
memoryCache.Set(cacheKey, result, new MemoryCacheEntryOptions()
.SetAbsoluteExpiration(TimeSpan.FromSeconds(10)));
//删除缓存
memoryCache.Remove(cacheKey);
//设置缓存优先级（程序压力大时，会根据优先级自动回收）
memoryCache.Set(cacheKey,result,new MemoryCacheEntryOptions()
.SetPriority(CacheItemPriority.NeverRemove));
//过期时缓存回调
memoryCache.Set(cacheKey, result, new MemoryCacheEntryOptions()
.SetAbsoluteExpiration(TimeSpan.FromSeconds(60))
.RegisterPostEvictionCallback((key, value, reason, substate)
=>
{
nlog.Warn($"键{key}值{value}改变,因为{reason}");
}));
//Token过期时，缓存回调
var cts = new CancellationTokenSource();
memoryCache.Set(cacheKey, result, new MemoryCacheEntryOptions()
.AddExpirationToken(new CancellationChangeToken(cts.Token))
.RegisterPostEvictionCallback((key, value, reason, substate)
=>
{
nlog.Warn($"键{key}值{value}改变,因为{reason}");
}));
}
ViewBag.Cache = result;
return View();
}在ASP.NET Core MVC 中有一个 Distributed Cache Tag Helper，它是依赖于MemoryCache组件的。
可以直接在试图上增加 distributed-cache 标签
@{
ViewData["Title"] = "Home Page";
}
<distributed-cache name="mycache" expires-after="TimeSpan.FromSeconds(10)">
<p>缓存项10秒过期(expires-after绝对过期时间)</p>
</distributed-cache>
<distributed-cache name="mycachenew" expires-sliding="TimeSpan.FromSeconds(10)">
<p>相对十秒(expires-sliding相对过期时间)</p>
@DateTime.Now
</distributed-cache>
<div>@ViewBag.Cache</div>
