# .NET 4.0中的缓存功能
.Net 4.0中有3种,System.Runtime.Caching,System.Web.Caching.Cache,Output.Cache。下面分别对这三者进行介绍:### 应用程序缓存 System.Runtime.Caching
-----------------------------.net4内置的高速缓存```private void button1_Click(object sender, EventArgs e){ ObjectCache objectCache = MemoryCache.Default;string value1 = objectCache["key1"] as string;
CacheItemPolicy policy = new CacheItemPolicy();
//--------------设置过期时间----------------
policy.AbsoluteExpiration = DateTime.Now.AddHours(1);objectCache.Set("key1", "11223366", policy);
value1 = objectCache["key1"] as string;
//---------------测试不同类型时 as 是否能自动转换---------
objectCache.Set("key1", 112233, policy);value1 = objectCache["key1"] as string;
//---------------测试Add方法,在键已经存在的情况下会不会报错------ bool b = objectCache.Add("key1", 112233, policy);//---------------测试Add方法,键不存在的情况------
b = objectCache.Add("key2", 445566, policy);int n = (int)objectCache.Get("key2") ;
}```### Web应用程序缓存 System.Web.Caching.Cache
-----------------------------Web程序的缓存,Asp.Net MVC4中使用ViewBag来传递参数。```
public ActionResult CacheTest(){ ViewBag.Message = "Web缓存";Cache cache = HttpRuntime.Cache;
if (cache["Key1"] == null)
{ cache.Add("Key1", "Value 1", null, DateTime.Now.AddSeconds(600), Cache.NoSlidingExpiration, CacheItemPriority.High, onRemove); } ` string s = cache["Key1"] as string; ViewBag.Key1 = s; ViewBag.Setting = "配置啊";return View();
}//-----------------Razor页面使用-------------------
@ViewBag.Key1``` ### 页面输出缓存 Output.Cache-----------------------------页面输出缓冲,Output.Cache是MVC的一个注解[Output.Cache]。在过期时间内,返回给浏览器304,表示页面内容未修改。```[OutputCache(Duration =20)]//设置过期时间为20秒public ActionResult ExampleCache(){ var timeStr =DateTime.Now.ToString("yyyy年MM月dd日 HH时mm分ss秒"); ViewBag.timeStr = timeStr; return View();}```