微软企业库的Cache

通常,应用程序可以将那些频繁访问的数据,以及那些需要大量处理时间来创建的数据存储在内存中,从而提高性能。基于微软的企业库,我们的快速创建一个缓存的实现。

新建PrismSample.Infrastructure.Cache

新建一个类库项目,将其命名为PrismSample.Infrastructure.Cache,然后从nuget中下载微软企业库的Cache。
微软企业库的Cache-LMLPHP

然后新建我们的CacheManager类:

using Microsoft.Practices.EnterpriseLibrary.Caching;
using System.ComponentModel.Composition; namespace PrismSample.Infrastructure.Cache
{
[Export("PrismSampleCache", typeof(ICacheManager))]
public class CacheManager : ICacheManager
{
ICacheManager _cacheManager; public CacheManager()
{
_cacheManager = CacheFactory.GetCacheManager("MemoryCacheManager");
} public object this[string key]
{
get
{
return _cacheManager[key];
}
} public int Count
{
get
{
return _cacheManager.Count;
}
} public void Add(string key, object value)
{
_cacheManager.Add(key, value);
} public void Add(string key, object value, CacheItemPriority scavengingPriority, ICacheItemRefreshAction refreshAction, params ICacheItemExpiration[] expirations)
{
_cacheManager.Add(key, value, scavengingPriority, refreshAction, expirations);
} public bool Contains(string key)
{
return _cacheManager.Contains(key);
} public void Flush()
{
_cacheManager.Flush();
} public object GetData(string key)
{
return _cacheManager.GetData(key);
} public void Remove(string key)
{
_cacheManager.Remove(key);
}
}
}

其中MemoryCacheManager是我们稍后需要在App.config文件中配置的。

修改生成后事件:

xcopy "$(TargetPath)" "$(SolutionDir)\PrismSample\bin\Debug\" /Y

微软企业库的Cache-LMLPHP

之所以添加生成后事件,是因为Cache的类库的引入不是通过Project间的项目引用来实现的,是在运行时MEF的容器去寻找指令集,所以我们把程序集都放置到运行目录下。

修改App.config配置文件

<?xml version="1.0" encoding="utf-8"?>
<configuration>
<configSections>
<section name="cachingConfiguration" type="Microsoft.Practices.EnterpriseLibrary.Caching.Configuration.CacheManagerSettings, Microsoft.Practices.EnterpriseLibrary.Caching" />
</configSections>
<startup>
<supportedRuntime version="v4.0" sku=".NETFramework,Version=v4.6.1" />
</startup>
<runtime>
<assemblyBinding xmlns="urn:schemas-microsoft-com:asm.v1">
<dependentAssembly>
<assemblyIdentity name="Microsoft.Practices.ServiceLocation" publicKeyToken="31bf3856ad364e35" culture="neutral" />
<bindingRedirect oldVersion="0.0.0.0-1.3.0.0" newVersion="1.3.0.0" />
</dependentAssembly>
</assemblyBinding>
</runtime>
<cachingConfiguration defaultCacheManager="MemoryCacheManager">
<cacheManagers>
<add name="MemoryCacheManager" type="Microsoft.Practices.EnterpriseLibrary.Caching.CacheManager, Microsoft.Practices.EnterpriseLibrary.Caching" expirationPollFrequencyInSeconds="60" maximumElementsInCacheBeforeScavenging="1000" numberToRemoveWhenScavenging="10" backingStoreName="NullBackingStore" />
</cacheManagers>
<backingStores>
<add type="Microsoft.Practices.EnterpriseLibrary.Caching.BackingStoreImplementations.NullBackingStore, Microsoft.Practices.EnterpriseLibrary.Caching"
name="NullBackingStore" />
</backingStores>
</cachingConfiguration>
</configuration>

配置文件的生成可以通过微软企业库的工具(配置方式)

修改Bootstrapper,将目录下符合条件的dll全部导入

using Prism.Mef;
using PrismSample.Infrastructure.Abstract.Presentation.Interface;
using System.ComponentModel.Composition.Hosting;
using System.Windows;
using Prism.Logging;
using PrismSample.Infrastructure.Logger;
using System.IO;
using System; namespace PrismSample
{
public class Bootstrapper : MefBootstrapper
{
private const string SEARCH_PATTERN = "PrismSample.Infrastructure.*.dll"; protected override DependencyObject CreateShell()
{
IViewModel shellViewModel = this.Container.GetExportedValue<IViewModel>("ShellViewModel");
return shellViewModel.View as DependencyObject;
} protected override void InitializeShell()
{
Application.Current.MainWindow = (Shell)this.Shell;
Application.Current.MainWindow.Show();
} protected override void ConfigureAggregateCatalog()
{
base.ConfigureAggregateCatalog(); //加载自己
this.AggregateCatalog.Catalogs.Add(new AssemblyCatalog(this.GetType().Assembly)); //加载当前目录
DirectoryInfo dirInfo = new DirectoryInfo(@".\");
foreach (FileInfo fileInfo in dirInfo.EnumerateFiles(SEARCH_PATTERN))
{
try
{
this.AggregateCatalog.Catalogs.Add(new AssemblyCatalog(fileInfo.FullName));
}
catch (Exception ex)
{
this.Logger.Log( string.Format("导入异常:{0}", ex.Message), Category.Exception, Priority.None);
}
}
} protected override ILoggerFacade CreateLogger()
{
return new Logger();
}
}
}

测试运行

修改ShellViewModel的构造函数

[ImportingConstructor]
public ShellViewModel([Import("ShellView", typeof(IView))]IView view,
[Import]ILoggerFacade logger,
[Import("PrismSampleCache", typeof(ICacheManager))] ICacheManager _cacheManager)
{
this.View = view;
this.View.DataContext = this; _cacheManager.Add("SampleValue", "CacheValue");
this._text = _cacheManager.GetData("SampleValue").ToString();
logger.Log("ShellViewModel Created", Category.Info, Priority.None);
}

运行结果:
微软企业库的Cache-LMLPHP

小结

本文用微软企业库实现了一个简单的缓存系统。
源码下载

参考信息

patterns & practices – Enterprise Library
黄聪:Microsoft Enterprise Library 5.0 系列教程(一) : Caching Application Block (初级)

05-11 04:07