上一篇博文地址：[Asp.net 5] Localization-简单易用的本地化-全球化信息
本文继续介绍asp.net 5多语言。今天重点讲的是多语言的resx文件。涉及到的工程有：Microsoft.Framework.Localization.Abstractions以及Microsoft.Framework.Localization。他们之间的类结构如下如所示：
- Abstractions包中，包含了定义在工程Microsoft.Framework.Localization.Abstractions的大部分类和接口
- Localization包中，包含了定义在工程Microsoft.Framework.Localization中的大部分类和接口
Microsoft.Framework.Localization.Abstractions
该工程定义了本地化（全球化）的基本接口，以及一些抽象类。
- LocalizedString 封装name、value等属性的结构体，用于表示本地化寻找的结果
- IStringLocalizer 本地化访问的基本接口，通过方法或者属性（通过扩展方法，使得方法和属性调用一套逻辑）获得LocalizedString结构体对象；本解决方案中，对资源文件就是该接口的 实例操作的
- IStringLocalizer<T> 本接口中未定义任何方法，是IStringLocalizer 的泛型版本
- StringLocalizer<TResourceSource>，该类是IStringLocalizer<T> 的实现类，内部分装IStringLocalizer 接口。使用了代理模式（前面我们介绍的配置文件、以及依赖注入都使用了该模式），所有方法都是内部IStringLocalizer对象的封装。该类的构造函数是IStringLocalizerFactory接口。
- IStringLocalizerFactory接口：根据不同的Type类型创建不同的IStringLocalizer对象
public struct LocalizedString
{
public LocalizedString([NotNull] string name, [NotNull] string value)
: this(name, value, resourceNotFound: false)
{ } public LocalizedString([NotNull] string name, [NotNull] string value, bool resourceNotFound)
{
Name = name;
Value = value;
ResourceNotFound = resourceNotFound;
} public static implicit operator string (LocalizedString localizedString)
{
return localizedString.Value;
} public string Name { get; } public string Value { get; } public bool ResourceNotFound { get; } public override string ToString() => Value;
}
LocalizedString
public interface IStringLocalizer : IEnumerable<LocalizedString>
{
LocalizedString this[string name] { get; } LocalizedString this[string name, params object[] arguments] { get; } IStringLocalizer WithCulture(CultureInfo culture);
}
IStringLocalizer
public interface IStringLocalizer<T> : IStringLocalizer
{ } public class StringLocalizer<TResourceSource> : IStringLocalizer<TResourceSource>
{
private IStringLocalizer _localizer; public StringLocalizer([NotNull] IStringLocalizerFactory factory)
{
_localizer = factory.Create(typeof(TResourceSource));
} public virtual IStringLocalizer WithCulture(CultureInfo culture) => _localizer.WithCulture(culture); public virtual LocalizedString this[[NotNull] string name] => _localizer[name]; public virtual LocalizedString this[[NotNull] string name, params object[] arguments] =>
_localizer[name, arguments]; public virtual LocalizedString GetString([NotNull] string name) => _localizer.GetString(name); public virtual LocalizedString GetString([NotNull] string name, params object[] arguments) =>
_localizer.GetString(name, arguments); public IEnumerator<LocalizedString> GetEnumerator() => _localizer.GetEnumerator(); IEnumerator IEnumerable.GetEnumerator() => _localizer.GetEnumerator();
}
StringLocalizer
根据上面的介绍，我们可以推断该类库的使用方式如下：
public void Test()
{
IStringLocalizerFactory factory=new ResourceManagerStringLocalizerFactory();
IStringLocalizer localizer=new StringLocalizer<TType>(factory);
//IStringLocalizer<TType> localizer=new StringLocalizer<TType>();
//localizer=localizer.WithCulture(CultureInfo.CurrentUICulture);
var localizedString=localizer.GetString(key);
}
[StringLocalizer<TResource>的作用就是隐藏具体IStringLocalizer，使我们不用关心是哪个IStringLocalizer，这样做对于直接书写代码可能看不出直接意义，但是如果使用依赖注入，则可以明显的看出好处，我们可以为IStringLocalizer<TType>直接注入StringLocalizer<TType>类]
[如果对于依赖注入了解不多，可以看下篇博客：DependencyInjection项目代码分析-目录，略长]
Microsoft.Framework.Localization
- ResourceManagerStringLocalizerFactory：创建ResourceManagerStringLocalizer类资源
- ResourceManagerStringLocalizer：resx多语言文件的访问器（实际该代码并未另起灶炉，而是使用了ResourceManager类）
- ResourceManagerWithCultureStringLocalizer：ResourceManagerStringLocalizer的子类，提供多语言访问接口。该类实际上是在父类中WithCulture中创建，而该方法内实际也是一个类似于代理模式的设计
- LocalizationServiceCollectionExtensions类：该类将ResourceManagerStringLocalizerFactory注入到IStringLocalizerFactory接口，StringLocalizer<T> 注入到IStringLocalizer<T> 接口。
public class ResourceManagerStringLocalizerFactory : IStringLocalizerFactory
{
private readonly IApplicationEnvironment _applicationEnvironment; public ResourceManagerStringLocalizerFactory([NotNull] IApplicationEnvironment applicationEnvironment)
{
_applicationEnvironment = applicationEnvironment;
} public IStringLocalizer Create([NotNull] Type resourceSource)
{
var typeInfo = resourceSource.GetTypeInfo();
var assembly = new AssemblyWrapper(typeInfo.Assembly);
var baseName = typeInfo.FullName;
return new ResourceManagerStringLocalizer(new ResourceManager(resourceSource), assembly, baseName);
} public IStringLocalizer Create([NotNull] string baseName, [NotNull] string location)
{
var assembly = Assembly.Load(new AssemblyName(location ?? _applicationEnvironment.ApplicationName)); return new ResourceManagerStringLocalizer(
new ResourceManager(baseName, assembly),
new AssemblyWrapper(assembly),
baseName);
}
}
ResourceManagerStringLocalizerFactory
public class ResourceManagerStringLocalizer : IStringLocalizer
{
private static readonly ConcurrentDictionary<string, IList<string>> _resourceNamesCache =
new ConcurrentDictionary<string, IList<string>>(); private readonly ConcurrentDictionary<string, object> _missingManifestCache =
new ConcurrentDictionary<string, object>(); private readonly ResourceManager _resourceManager;
private readonly AssemblyWrapper _resourceAssemblyWrapper;
private readonly string _resourceBaseName; public ResourceManagerStringLocalizer(
[NotNull] ResourceManager resourceManager,
[NotNull] Assembly resourceAssembly,
[NotNull] string baseName)
: this(resourceManager, new AssemblyWrapper(resourceAssembly), baseName)
{ } public ResourceManagerStringLocalizer(
[NotNull] ResourceManager resourceManager,
[NotNull] AssemblyWrapper resourceAssemblyWrapper,
[NotNull] string baseName)
{
_resourceAssemblyWrapper = resourceAssemblyWrapper;
_resourceManager = resourceManager;
_resourceBaseName = baseName;
} public virtual LocalizedString this[[NotNull] string name]
{
get
{
var value = GetStringSafely(name, null);
return new LocalizedString(name, value ?? name, resourceNotFound: value == null);
}
} public virtual LocalizedString this[[NotNull] string name, params object[] arguments]
{
get
{
var format = GetStringSafely(name, null);
var value = string.Format(format ?? name, arguments);
return new LocalizedString(name, value, resourceNotFound: format == null);
}
} public IStringLocalizer WithCulture(CultureInfo culture)
{
return culture == null
? new ResourceManagerStringLocalizer(_resourceManager, _resourceAssemblyWrapper, _resourceBaseName)
: new ResourceManagerWithCultureStringLocalizer(_resourceManager,
_resourceAssemblyWrapper,
_resourceBaseName,
culture);
} protected string GetStringSafely([NotNull] string name, CultureInfo culture)
{
var cacheKey = $"name={name}&culture={(culture ?? CultureInfo.CurrentUICulture).Name}"; if (_missingManifestCache.ContainsKey(cacheKey))
{
return null;
} try
{
return culture == null ? _resourceManager.GetString(name) : _resourceManager.GetString(name, culture);
}
catch (MissingManifestResourceException)
{
_missingManifestCache.TryAdd(cacheKey, null);
return null;
}
} public virtual IEnumerator<LocalizedString> GetEnumerator() => GetEnumerator(CultureInfo.CurrentUICulture); IEnumerator IEnumerable.GetEnumerator() => GetEnumerator(); protected IEnumerator<LocalizedString> GetEnumerator([NotNull] CultureInfo culture)
{
var resourceNames = GetResourceNamesFromCultureHierarchy(culture); foreach (var name in resourceNames)
{
var value = GetStringSafely(name, culture);
yield return new LocalizedString(name, value ?? name, resourceNotFound: value == null);
}
} internal static void ClearResourceNamesCache() => _resourceNamesCache.Clear(); private IEnumerable<string> GetResourceNamesFromCultureHierarchy(CultureInfo startingCulture)
{
var currentCulture = startingCulture;
var resourceNames = new HashSet<string>(); while (true)
{
try
{
var cultureResourceNames = GetResourceNamesForCulture(currentCulture);
foreach (var resourceName in cultureResourceNames)
{
resourceNames.Add(resourceName);
}
}
catch (MissingManifestResourceException) { } if (currentCulture == currentCulture.Parent)
{
// currentCulture begat currentCulture, probably time to leave
break;
} currentCulture = currentCulture.Parent;
} return resourceNames;
} private IList<string> GetResourceNamesForCulture(CultureInfo culture)
{
var resourceStreamName = _resourceBaseName;
if (!string.IsNullOrEmpty(culture.Name))
{
resourceStreamName += "." + culture.Name;
}
resourceStreamName += ".resources"; var cacheKey = $"assembly={_resourceAssemblyWrapper.FullName};resourceStreamName={resourceStreamName}"; var cultureResourceNames = _resourceNamesCache.GetOrAdd(cacheKey, key =>
{
var names = new List<string>();
using (var cultureResourceStream = _resourceAssemblyWrapper.GetManifestResourceStream(key))
using (var resources = new ResourceReader(cultureResourceStream))
{
foreach (DictionaryEntry entry in resources)
{
var resourceName = (string)entry.Key;
names.Add(resourceName);
}
} return names;
}); return cultureResourceNames;
}
}
ResourceManagerStringLocalizer
public class ResourceManagerWithCultureStringLocalizer : ResourceManagerStringLocalizer
{
private readonly CultureInfo _culture; public ResourceManagerWithCultureStringLocalizer(
[NotNull] ResourceManager resourceManager,
[NotNull] Assembly assembly,
[NotNull] string baseName,
[NotNull] CultureInfo culture)
: base(resourceManager, assembly, baseName)
{
_culture = culture;
} public ResourceManagerWithCultureStringLocalizer(
[NotNull] ResourceManager resourceManager,
[NotNull] AssemblyWrapper assemblyWrapper,
[NotNull] string baseName,
[NotNull] CultureInfo culture)
: base(resourceManager, assemblyWrapper, baseName)
{
_culture = culture;
} public override LocalizedString this[[NotNull] string name]
{
get
{
var value = GetStringSafely(name, _culture);
return new LocalizedString(name, value ?? name);
}
} public override LocalizedString this[[NotNull] string name, params object[] arguments]
{
get
{
var format = GetStringSafely(name, _culture);
var value = string.Format(_culture, format ?? name, arguments);
return new LocalizedString(name, value ?? name, resourceNotFound: format == null);
}
} public override IEnumerator<LocalizedString> GetEnumerator() => GetEnumerator(_culture);
}
ResourceManagerWithCultureStringLocalizer
public static class LocalizationServiceCollectionExtensions
{
public static IServiceCollection AddLocalization([NotNull] this IServiceCollection services)
{
services.TryAdd(new ServiceDescriptor(
typeof(IStringLocalizerFactory),
typeof(ResourceManagerStringLocalizerFactory),
ServiceLifetime.Singleton));
services.TryAdd(new ServiceDescriptor(
typeof(IStringLocalizer<>),
typeof(StringLocalizer<>),
ServiceLifetime.Transient)); return services;
}
}
LocalizationServiceCollectionExtensions
由于依赖注入的关系所以我们可以将代码简单的修改成如下：
//var services = new ServiceCollection();
//services.AddLocalization(); 系统初始化时执行过该部分代码
public string Test(string key)
{
var localizer=Provider.GetService<IStringLocalizer<RescoureType>>();
//localizer=localizer.WithCulture(CultureInfo.CurrentUICulture);
var localizedString=localizer.GetString(key);
if(localizedString.ResourceNotFound){
reuturn null;
}
return localizedString.Value;
}