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标题: 推荐一个.NET缓存类：BaseCache<T>

作者: dnawo

日期: 2011-11-25 09:27 AM

分类: Win编程

内容: 这个类原本存在于一个外包项目上，是外包公司写的，感觉比较不错，于是把它提取了出来。
一、缓存基类BaseCache<T>
复制内容到剪贴板 程序代码using System;
using System.Collections;
using System.Collections.Generic;
using System.Data;
namespace ConsoleApplication1
{  
    /// <summary>
    /// 缓存基类
    /// </summary>
    /// <typeparam name="T"></typeparam>
    public abstract class BaseCache<T>
    {
        string _tablename;
        static Hashtable cache = new Hashtable();        
        /// <summary>
        /// 构造函数
        /// </summary>
        /// <param name="cachetable"></param>
        protected BaseCache(string cachetable)
        {
            _tablename = cachetable;
        }
        /// <summary>
        /// 单条记录转为实体(抽象方法)
        /// </summary>
        /// <param name="idr"></param>
        /// <returns></returns>
        protected abstract T Build(IDataReader idr);
        /// <summary>
        /// 加载数据到缓存
        /// </summary>
        /// <returns></returns>
        public bool LoadIntoCache()
        {
            try
            {
                List<T> dataforcache = new List<T>();
                using (IDataReader idr = SqlHelper.ExecuteReader(string.Format("select * from {0} with(nolock)", _tablename)))
                {
                    while (idr.Read())
                    {
                        T obj = Build(idr);
                        dataforcache.Add(obj);
                    }
                }
                cache.Add(_tablename, dataforcache);
                return true;
            }
            catch (Exception ex)
            {
                throw ex;
            }
            return false;
        }
        /// <summary>
        /// 读取缓存数据
        /// </summary>
        public List<T> Cache
        {
            get
            {
                if (!cache.ContainsKey(_tablename))
                    LoadIntoCache();
                return (List<T>)cache[_tablename];
            }
        }
        /// <summary>
        /// 清空缓存数据
        /// </summary>
        /// <returns></returns>
        public bool Clear()
        {
            try
            {
                if (cache.ContainsKey(_tablename))
                    cache.Remove(_tablename);
                return true;
            }
            catch { }
            return false;
        }        
    }    
}
二、具体缓存类及其实体类
复制内容到剪贴板 程序代码using System;
using System.Data;
namespace ConsoleApplication1
{
    /// <summary>
    /// 实体类
    /// </summary>
    public class CacheForTable1TBData
    {
        int _id = 0;
        string _name = string.Empty;
        public CacheForTable1TBData(int id, string name)
        {
            _id = id;
            _name = name;
        }
        public int Id
        {
            get { return _id; }
        }
        public string Name
        {
            get { return _name; }
        }
    }
    /// <summary>
    /// 具体缓存类
    /// </summary>
    public class CacheForTable1TB : BaseCache<CacheForTable1TBData>
    {
        #region 构造函数
        public CacheForTable1TB()
            : base("Table1TB")
        {
        }
        #endregion
        #region 抽象方法实现
        protected override CacheForTable1TBData Build(IDataReader idr)
        {
            int id = 0;
            string name = string.Empty;
            if (idr["Id"] != DBNull.Value)
                id = Convert.ToInt32(idr["Id"]);
            if (idr["Name"] != DBNull.Value)
                name = idr["Name"].ToString();
            return new CacheForTable1TBData(id, name);
        }
        #endregion
    }
}
使用示例：
复制内容到剪贴板 程序代码using System;
using System.Linq;
namespace ConsoleApplication1
{
    class Program
    {
        static void Main(string[] args)
        {
            var query = (new CacheForTable1TB().Cache)
                .Where<CacheForTable1TBData>(item => item.Id == 10000)
                .FirstOrDefault<CacheForTable1TBData>();
            Console.WriteLine(query.Name);
            Console.ReadKey();
        }
    }
}
当存在多个具体的缓存类时，有时需要对缓存进行更新等，一个个去调用Clear方法比较麻烦，这时可以新建一个缓存管理类。
三、缓存管理类DataCacheTaker
复制内容到剪贴板 程序代码using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
namespace ConsoleApplication1
{
    /// <summary>
    /// 缓存管理类
    /// </summary>
    public class DataCacheTaker
    {
        /// <summary>
        ///
        /// </summary>
        public static List<CacheForTable1TBData> Table1TB
        {
            get { return (new CacheForTable1TB()).Cache; }
        }
        /// <summary>
        ///
        /// </summary>
        public static List<CacheForTable2TBData> Table2TB
        {
            get { return (new CacheForTable2TB()).Cache; }
        }
        /// <summary>
        /// 更新缓存
        /// </summary>
        /// <returns></returns>
        public static bool RefreshCache()
        {
            try
            {
                if ((new CacheForTable1TB()).Clear()) { var tmp = (new CacheForTable1TB()).Cache; }
                if ((new CacheForTable2TB()).Clear()) { var tmp = (new CacheForTable2TB()).Cache; }
                return true;
            }
            catch { }
            return false;
        }
    }
}
使用示例：
复制内容到剪贴板 程序代码using System;
using System.Linq;
namespace ConsoleApplication1
{
    class Program
    {
        static void Main(string[] args)
        {
            DataCacheTaker.RefreshCache();
            var query = DataCacheTaker.Table1TB
                .Where<CacheForTable1TBData>(item => item.Id == 10000)
                .FirstOrDefault<CacheForTable1TBData>();
            Console.WriteLine(query.Name);
            Console.ReadKey();
        }
    }
}

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