ASP.NET缓存 Cache之数据缓存

HttpContext.Current.Cache["One"] = "1";

string cacheKey = "Two";
object cacheValue = HttpContext.Current.Cache.Get(cacheKey);

if(cacheValue == null)
{
    cacheValue = WebConfigurationManager.ConnectionStrings["ApplicationServices"].ConnectionString;

    HttpContext.Current.Cache.Insert(cacheKey, cacheValue);
}

//显示指定缓存的Key 与 Value
this.ShowMessage(cacheKey, cacheValue.ToString());

string cacheKey = "__cache__students";

DataSet dataSet = this.Cache.Get(cacheKey) as DataSet;

if(dataSet == null)
{
    dataSet = new DataSet();

    //加载XML并填充至DataSet
    dataSet.ReadXml(this.Server.MapPath(@"XMLFile.xml"));

    //加入缓存，并设定'绝对过期时间'为5分钟
    this.Cache.Insert(cacheKey, dataSet, null, DateTime.Now.AddMinutes(5), System.Web.Caching.Cache.NoSlidingExpiration);
}

//绑定DataGrid数据
grdDefault.DataSource = dataSet;
grdDefault.DataBind();

CacheItemRemovedCallback)插入Cache

public partial class PriorityAndCallbackDemo : System.Web.UI.Page
{
    #region 静态字段
    static bool CacheItemRemoved = false;
    static CacheItemRemovedReason Reason;
    static string CacheItemKey = "fw__cache__students";
    #endregion

    #region 事件处理
    //页面加载
    protected void Page_Load(object sender, EventArgs e)
    {
        //缓存项已移除
        if(PriorityAndCallbackDemo.CacheItemRemoved)
        {
            ltMessage.Text = string.Format("Key={0}已从缓存移出，原因为：{1}", PriorityAndCallbackDemo.CacheItemKey, PriorityAndCallbackDemo.Reason.ToString());
        }
    }

    //'添加缓存'按钮 点击事件 处理
    protected void btnAddCache_Click(object sender, EventArgs e)
    {
        DataSet dataSet = this.Cache.Get(PriorityAndCallbackDemo.CacheItemKey) as DataSet;

        if(dataSet == null)
        {
            dataSet = new DataSet();
            dataSet.ReadXml(this.Server.MapPath(@"XMLFile.xml"));

            //使用 Web.config 作为缓存过期依赖项
            CacheDependency dependency = new CacheDependency(this.Server.MapPath(@"Web.config"), DateTime.Now);

            //加入缓存，设定优先级为默认级别
            this.Cache.Insert(PriorityAndCallbackDemo.CacheItemKey, dataSet, dependency, DateTime.Now.AddMinutes(1), System.Web.Caching.Cache.NoSlidingExpiration, CacheItemPriority.Default, new CacheItemRemovedCallback(this.CacheItemRemovedHandler));
        }

        //绑定GridView数据
        grdDefault.DataSource = dataSet;
        grdDefault.DataBind();
    }

    //'移除缓存'按钮 点击事件 处理
    protected void btnRemoveCache_Click(object sender, EventArgs e)
    {
        if(this.Cache[PriorityAndCallbackDemo.CacheItemKey] != null)
        {
            this.Cache.Remove(PriorityAndCallbackDemo.CacheItemKey);
        }
    }
    #endregion

    #region 私有方法
    //缓存项移除事件处理
    private void CacheItemRemovedHandler(string key, object value, CacheItemRemovedReason relason)
    {
        PriorityAndCallbackDemo.CacheItemRemoved = true;
        PriorityAndCallbackDemo.Reason = relason;
    }
    #endregion
}

Cache.Insert("data", "123", null , DateTime.MaxValue, TimeSpan.FromMinutes(10));

Cache.Insert("data", "123", null , DateTime.Now.AddMinutes(60), TimeSpan.Zero);

System.Web.Caching.CacheDependency cacheDependency = new System.Web.Caching.CacheDependency (null, new string [] { "time" });
Cache.Insert( "number", ++num, cacheDependency);
 
依赖于文件或文件夹
 
System.Web.Caching. CacheDependency cacheDependency = new System.Web.Caching.CacheDependency ( "test.xml");
当test.xml文件删除、更新时自动从缓存中移除
 
System.Web.Caching.CacheDependency cacheDependency = new System.Web.Caching.CacheDependency(null, new string[] { "time" });
Cache.Insert("test", "123", cacheDependency);

 
移除项目回调
 Cache.Insert("test", "123", null , DateTime.Now.AddSeconds(10), TimeSpan.Zero, new CacheItemUpdateCallback(Test));
 
 
 private void Test(string key, CacheItemUpdateReason reason, out object expensiveObject, out CacheDependency dependency, out DateTime absoluteExpiration, out TimeSpan slidingExpiration)
    {
 
    }