数据缓存助手类

using System;
using System.Collections.Generic;
using System.Text;
using System.Web.Caching;
using System.Web.UI;
namespace ASPNETCaCheHelpers
{
    /// <summary>
    /// 在ASPNET应用程序中使用缓存的助手类
    /// </summary>
    public class CaCheHelper
    {
        /// <summary>
        /// 一个缓存类实例
        /// </summary>
        private Cache cache;
        /// <summary>
        /// 缓存池实例
        /// </summary>
        public Cache Cacheobj
        {
            set
            {
                this.cache = value;
            }
        }
        /// <summary>
        /// 添加一个基于文件依赖的缓存
        /// </summary>
        /// <param name="cachename">缓存的名称</param>
        /// <param name="value">要缓存的数据</param>
        /// <param name="filepath">缓存依赖的文件路径</param>
        /// <param name="callback">当缓存被清空时要执行的委托</param>
        /// <returns>返回缓存添加结果True添加成功False失败</returns>
        public bool AddFileCacheDependency(string cachename,object value,string filepath,CacheItemRemovedCallback callback)
        {
            CacheDependency cachedependency = new CacheDependency(filepath);
            if (cache.Add(cachename, value, cachedependency, Cache.NoAbsoluteExpiration, Cache.NoSlidingExpiration, CacheItemPriority.Normal, callback) != null)
            {
                return true;
            }
            return false;
        }
        /// <summary>
        /// 添加一个基于数据库依赖的缓存
        /// </summary>
        /// <param name="cachename">缓存的名称</param>
        /// <param name="databasename">缓存依赖的数据库名称</param>
        /// <param name="cachetable">缓存依赖的数据表名称</param>
        /// <param name="value">要缓存的数据</param>
        /// <param name="callback">当缓存被清空时要执行的委托</param>
        /// <returns>返回缓存添加结果True添加成功False失败</returns>
        public bool AddDataBaseCacheDependency(string cachename,string databasename,string cachetable, object value, CacheItemRemovedCallback callback)
        {
            SqlCacheDependency cachedependency = new SqlCacheDependency(databasename, cachetable);
            if (cache.Add(cachename, value, cachedependency, Cache.NoAbsoluteExpiration, Cache.NoSlidingExpiration, CacheItemPriority.Normal, callback) != null)
            {
                return true;
            }
            return false;
        }
        /// <summary>
        /// 获取缓存数据
        /// </summary>
        /// <param name="cachekey">缓存中指定缓存项名称</param>
        /// <returns>返回缓存数据，若不存在指定缓存项则返回null</returns>
        public object GetCacheData(string cachekey)
        {
            if (cache[cachekey] != null)
            {
                return cache[cachekey];
            }
            return null;
        }
    }
}