C#快取主要是為了提高資料的讀取速度。因為伺服器和應用客戶端之間存在著流量的瓶頸，所以讀取大容量資料時，使用快取來直接為客戶端服務，可以減少客戶端與伺服器端的資料互動，從而大大提高程式的效能。

以下為工作中經常用到的快取操作公用類庫整理：

using System;
using System.Collections;
using System.Collections.Generic;
using System.Linq;
using System.Web;
using System.Web.Caching;
using System.Web.Hosting;
namespace ECS.Utility
{
    /// <summary>
    /// Caching 的摘要說明
    /// </summary>
    public class Caching
    {

        /// <summary>
        /// 獲取當前應用程式指定CacheKey的Cache值
        /// </summary>
        /// <param name="CacheKey"></param>
        /// <returns></returns>y
        public static object GetCache(string CacheKey)
        {
            System.Web.Caching.Cache objCache = HttpRuntime.Cache;
            return objCache[CacheKey];
        }

        /// <summary>
        /// 設定當前應用程式指定CacheKey的Cache值
        /// </summary>
        /// <param name="CacheKey"></param>
        /// <param name="objObject"></param>
        public static void SetCache(string CacheKey, object objObject)
        {
            System.Web.Caching.Cache objCache = HttpRuntime.Cache;
            objCache.Insert(CacheKey, objObject);
        }


        /// <summary>
        /// 設定當前應用程式指定CacheKey的Cache值
        /// </summary>
        /// <param name="CacheKey"></param>
        /// <param name="objObject"></param>
        public static void SetCache(string CacheKey, object objObject, DateTime absoluteExpiration, TimeSpan slidingExpiration)
        {
            System.Web.Caching.Cache objCache = HttpRuntime.Cache;
            objCache.Insert(CacheKey, objObject, null, absoluteExpiration, slidingExpiration);
        }

        /// <summary>
        /// 清除單一鍵快取
        /// </summary>
        /// <param name="key"></param>
        public static void RemoveKeyCache(string CacheKey)
        {
            try
            {
                System.Web.Caching.Cache objCache = HttpRuntime.Cache;
                objCache.Remove(CacheKey);
            }
            catch { }
        }

        /// <summary>
        /// 清除所有快取
        /// </summary>
        public static void RemoveAllCache()
        {
            System.Web.Caching.Cache _cache = HttpRuntime.Cache;
            IDictionaryEnumerator CacheEnum = _cache.GetEnumerator();
            if (_cache.Count > 0)
            {
                ArrayList al = new ArrayList();
                while (CacheEnum.MoveNext())
                {
                    al.Add(CacheEnum.Key);
                }
                foreach (string key in al)
                {
                    _cache.Remove(key);
                }
            }
        }

        /// <summary>
        /// 以列表形式返回已存在的所有快取 
        /// </summary>
        /// <returns></returns> 
        public static ArrayList ShowAllCache()
        {
            ArrayList al = new ArrayList();
            System.Web.Caching.Cache _cache = HttpRuntime.Cache;
            if (_cache.Count > 0)
            {
                IDictionaryEnumerator CacheEnum = _cache.GetEnumerator();
                while (CacheEnum.MoveNext())
                {
                    al.Add(CacheEnum.Key);
                }
            }
            return al;
        }


    }
}