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
/// <summary>
/// 基于MemoryCache的缓存辅助类
/// </summary>
public static class MemoryCacheHelper
{
private static readonly Object _locker = new object(); public static T FindCacheItem<T>(string key, Func<T> 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];
}
/// <summary>
/// 移除缓存
/// </summary>
/// <param name="key"></param>
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<Person>(cacheKey,
() =>
{
return new Person() { Id = Guid.NewGuid(), Name = "wolfy" };
}, new TimeSpan(, , ));
if (p != null)
{
Console.WriteLine(p.ToString());
}
Console.WriteLine("获取缓存中数据");
Person p2 = MemoryCacheHelper.FindCacheItem<Person>(cacheKey,
() =>
{
return new Person() { Id = Guid.NewGuid(), Name = "wolfy" };
}, new TimeSpan(, , ));
if (p2 != null)
{
Console.WriteLine(p2.ToString());
}
MemoryCacheHelper.RemoveCache(cacheKey);
Person p3 = MemoryCacheHelper.FindCacheItem<Person>(cacheKey,
() =>
{
return new Person() { Id = Guid.NewGuid(), Name = "wolfy" };
}, new TimeSpan(, , ));
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
http://www.cnblogs.com/ldy_ai/p/3939954.html
https://msdn.microsoft.com/en-us/library/system.runtime.caching.memorycache(v=vs.110).aspx