摘要

在对winform做的项目优化的时候，首先想到的是对查询，并不经常变化的数据进行缓存，但对web项目来说有System.Web.Caching.Cache类进行缓存，那么winform端该如何呢？你可能会想到，存到文件中，但那可能有问题，文件操作权限问题，IO操作性能问题。

解决办法

针对exe的项目，可以使用MemoryCache这个类，进行内存级别的缓存。

辅助类

/// 
    /// 基于MemoryCache的缓存辅助类    /// 
    public static class MemoryCacheHelper    {        private static readonly Object _locker = new object();        public static T FindCacheItem
     
      (string key, Func
      
        cachePopulate, TimeSpan? slidingExpiration = null,  DateTime? absoluteExpiration = null)        {            if (String.IsNullOrWhiteSpace(key))            {                throw new ArgumentException("Invalid cache key");            }            if (cachePopulate == null)            {                throw new ArgumentNullException("cachePopulate");            }            if (slidingExpiration == null && absoluteExpiration == null)            {                throw new ArgumentException("Either a sliding expiration or absolute must be provided");            }            if (MemoryCache.Default[key] == null)            {                lock (_locker)                {                    if (MemoryCache.Default[key] == null)                    {                        var item = new CacheItem(key, cachePopulate());                        var policy = CreatePolicy(slidingExpiration, absoluteExpiration);                        MemoryCache.Default.Add(item, policy);                    }                }            }            return (T)MemoryCache.Default[key];        }        /// 
       
        /// 移除缓存        /// 
        /// 
               public static void RemoveCache(string key)        {            MemoryCache.Default.Remove(key);        }        private static CacheItemPolicy CreatePolicy(TimeSpan? slidingExpiration, DateTime? absoluteExpiration)        {            var policy = new CacheItemPolicy();            if (absoluteExpiration.HasValue)            {                policy.AbsoluteExpiration = absoluteExpiration.Value;            }            else if (slidingExpiration.HasValue)            {                policy.SlidingExpiration = slidingExpiration.Value;            }            policy.Priority = CacheItemPriority.Default;            return policy;        }    }
      
     

测试

class Program    {        static void Main(string[] args)        {            string cacheKey = "person_key";            Person p = MemoryCacheHelper.FindCacheItem
     
      (cacheKey,                () =>                {                    return new Person() { Id = Guid.NewGuid(), Name = "wolfy" };                }, new TimeSpan(0, 30, 0));            if (p != null)            {                Console.WriteLine(p.ToString());            }            Console.WriteLine("获取缓存中数据");            Person p2 = MemoryCacheHelper.FindCacheItem
      
       (cacheKey,                () =>                {                    return new Person() { Id = Guid.NewGuid(), Name = "wolfy" };                }, new TimeSpan(0, 30, 0));            if (p2 != null)            {                Console.WriteLine(p2.ToString());            }            MemoryCacheHelper.RemoveCache(cacheKey);            Person p3 = MemoryCacheHelper.FindCacheItem
       
        (cacheKey,               () =>               {                   return new Person() { Id = Guid.NewGuid(), Name = "wolfy" };               }, new TimeSpan(0, 30, 0));            if (p3 != null)            {                Console.WriteLine(p3.ToString());            }            Console.Read();        }    }    public class Person    {        public Guid Id { set; get; }        public string Name { set; get; }        public override string ToString()        {            return Id.ToString() + "\t" + Name;        }    }
       
      
     

参考