ASP.NET 8 – 单个 Resx 文件构建多语言应用程序
构建多语言 ASP.NET 8 MVC 应用程序的实用指南
1. 需要更新的教程
有许多关于如何为 ASP.NET Core 8 MVC 构建多语言应用程序的教程，但许多都已过时，不适用于旧版本的 .NET，或者在如何解决将所有语言资源 strings 集中到单个文件的问题上含糊不清。因此，计划提供实际操作说明，以及代码示例和概念验证应用程序。
1.1 本系列文章
本系列文章包括：
- ASP.NET 8 – 多语言应用程序（单 Resx 文件）
- ASP.NET 8 – 多语言应用程序（单 Resx 文件）– 第 2 部分 – 替代方法
- ASP.NET 8 – 多语言应用程序（单 Resx 文件）– 第 3 部分 – 表单验证字符串
- ASP.NET 8 – 多语言应用程序（单 Resx 文件）– 第 4 部分 – 资源管理器
2. 多语言站点、国际化和本地化
这里我将不解释拥有多种语言站点的优势，以及本地化和国际化是什么。你可以在互联网的许多地方找到相关信息（参见 [4]）。我将专注于如何在 ASP.NET Core 8 MVC 中实际构建这样的站点。如果你不确定 .resx 文件是什么，那么本文可能不适合你。
3. 共享资源方法
默认情况下，ASP.NET Core 8 MVC 技术为每个控制器和视图设想了单独的资源文件 .resx。但大多数人不喜欢这样，因为在应用程序的不同地方，大多数多语言 strings 是相同的，我们希望它们都放在同一个地方。文献 [1] 将这种方法称为“共享资源”方法。为了实现这一点，我们将创建一个标记类 SharedResoureces.cs 来 agrup（分组）所有资源。然后，在我们的应用程序中，我们将调用依赖注入 (DI) 来注入这个特定的类/类型，而不是特定的控制器/视图。这是 Microsoft 文档 [1] 中提到的一点技巧，它在 StackOverflow 文章 [6] 中引起了一些困惑。我们计划在这里将其弄清楚。虽然 [1] 中已解释了所有内容，但所需的是一些实际示例，就像我们在这里提供的一个示例。
4. 多语言应用程序步骤
4.1 配置本地化服务和中间件
本地化服务在 Program.cs 中配置
private static void AddingMultiLanguageSupportServices(WebApplicationBuilder? builder)
{
if (builder == null) { throw new Exception("builder==null"); };
builder.Services.AddLocalization(options => options.ResourcesPath = "Resources");
builder.Services.AddMvc()
.AddViewLocalization(LanguageViewLocationExpanderFormat.Suffix);
builder.Services.Configure<RequestLocalizationOptions>(options =>
{
var supportedCultures = new[] { "en", "fr", "de", "it" };
options.SetDefaultCulture(supportedCultures[0])
.AddSupportedCultures(supportedCultures)
.AddSupportedUICultures(supportedCultures);
});
}
private static void AddingMultiLanguageSupport(WebApplication? app)
{
app?.UseRequestLocalization();
}
4.2 创建标记类 SharedResources.cs
这只是一个用于 agrupir 共享资源的虚拟标记类。我们需要它是因为它的名称和类型。
似乎命名空间需要与应用程序根命名空间相同，而根命名空间又需要与程序集名称相同。我在更改命名空间时遇到了一些问题，它不起作用。如果对你不起作用，你可以尝试在 DI 指令中使用完整的类名，如下所示：
IStringLocalizer<SharedResources01.SharedResource> StringLocalizer
“SharedResource”这个名字没有什么魔法，你可以将其命名为“MyResources”，然后在代码中更改所有对“MyResources”的引用，一切仍然会正常工作。
位置似乎可以是任何文件夹，尽管一些文章 ([6] 声称需要放在项目根文件夹，但在本示例中我没有遇到这样的问题。对我来说，看起来可以是任何文件夹，只要保持你的命名空间整洁即可。
//SharedResource.cs===================================================
namespace SharedResources01
{
/*
* This is just a dummy marker class to group shared resources
* We need it for its name and type
*
* It seems the namespace needs to be the same as app root namespace
* which needs to be the same as the assembly name.
* I had some problems when changing the namespace, it would not work.
* If it doesn't work for you, you can try to use full class name
* in your DI instruction, like this one:
* IStringLocalizer<SharedResources01.SharedResource> StringLocalizer
*
* There is no magic in the name "SharedResource", you can
* name it "MyResources" and change all references in the code
* to "MyResources" and all will still work
*
* Location seems can be any folder, although some
* articles claim it needs to be the root project folder
* I do not see such problems in this example.
* To me looks it can be any folder, just keep your
* namespace tidy.
*/
public class SharedResource
{
}
}
4.3 创建语言资源文件
在“Resources”文件夹中，创建你的语言资源文件，并确保将它们命名为 SharedResources.xx.resx。
4.4 选择语言/区域性
基于 [5]，本地化服务有三个默认提供程序
QueryStringRequestCultureProviderCookieRequestCultureProviderAcceptLanguageHeaderRequestCultureProvider
由于大多数应用程序通常会提供一种机制来使用 ASP.NET Core 区域性 cookie 来设置区域性，因此在我们的示例中，我们将只关注这种方法。
这是设置 .AspNetCore.Culture cookie 的代码
private void ChangeLanguage_SetCookie(HttpContext myContext, string? culture)
{
if(culture == null) { throw new Exception("culture == null"); };
//this code sets .AspNetCore.Culture cookie
myContext.Response.Cookies.Append(
CookieRequestCultureProvider.DefaultCookieName,
CookieRequestCultureProvider.MakeCookieValue(new RequestCulture(culture)),
new CookieOptions { Expires = DateTimeOffset.UtcNow.AddMonths(1) }
);
}
可以使用 Chrome DevTools 轻松查看 Cookie
我构建了一个小型应用程序来演示它，这是我更改语言的屏幕
请注意，我在页脚添加了一些调试信息，以显示 **请求语言 Cookie** 的值，以查看应用程序是否按预期工作。
4.5 在控制器中使用本地化服务
在控制器中，当然，依赖注入 (DI) 会注入并填充所有依赖项。关键是我们请求的是特定的 type=SharedResource。
如果对你不起作用，你可以尝试在 DI 指令中使用完整的类名，如下所示：
IStringLocalizer<SharedResources01.SharedResource> stringLocalizer.
这是代码片段：
public class HomeController : Controller
{
private readonly ILogger<HomeController> _logger;
private readonly IStringLocalizer<SharedResource> _stringLocalizer;
private readonly IHtmlLocalizer<SharedResource> _htmlLocalizer;
/* Here is, of course, the Dependency Injection (DI) coming in and filling
* all the dependencies. The key thing is we are asking for a specific
* type=SharedResource.
* If it doesn't work for you, you can try to use full class name
* in your DI instruction, like this one:
* IStringLocalizer<SharedResources01.SharedResource> stringLocalizer
*/
public HomeController(ILogger<HomeController> logger,
IStringLocalizer<SharedResource> stringLocalizer,
IHtmlLocalizer<SharedResource> htmlLocalizer)
{
_logger = logger;
_stringLocalizer = stringLocalizer;
_htmlLocalizer = htmlLocalizer;
}
//================================
public IActionResult LocalizationExample(LocalizationExampleViewModel model)
{
//so, here we use IStringLocalizer
model.IStringLocalizerInController = _stringLocalizer["Wellcome"];
//so, here we use IHtmlLocalizer
model.IHtmlLocalizerInController = _htmlLocalizer["Wellcome"];
return View(model);
}
4.6 在视图中使用本地化服务
在视图中，当然，依赖注入 (DI) 会注入并填充所有依赖项。关键是我们请求的是特定的 type=SharedResource。
如果对你不起作用，你可以尝试在 DI 指令中使用完整的类名，如下所示：
IStringLocalizer<SharedResources01.SharedResource> stringLocalizer
这是代码片段：
@* LocalizationExample.cshtml ====================================================*@
@using Microsoft.AspNetCore.Mvc.Localization
@using Microsoft.Extensions.Localization
@model LocalizationExampleViewModel
@* Here is of course the Dependency Injection (DI) coming in and filling
all the dependencies. The key thing is we are asking for a specific
type=SharedResource.
If it doesn't work for you, you can try to use full class name
in your DI instruction, like this one:
@inject IStringLocalizer<SharedResources01.SharedResource> StringLocalizer
*@
@inject IStringLocalizer<SharedResource> StringLocalizer
@inject IHtmlLocalizer<SharedResource> HtmlLocalizer
@{
<div style="width:600px">
<p class="bg-info">
IStringLocalizer Localized in Controller:
@Model.IStringLocalizerInController
</p>
<p class="bg-info">
@{
string? text1 = StringLocalizer["Wellcome"];
}
IStringLocalizer Localized in View: @text1
</p>
<p class="bg-info">
IHtmlLocalizer Localized in Controller:
@Model.IHtmlLocalizerInController
</p>
<p class="bg-info">
@{
string? text2 = "Wellcome";
}
IHtmlLocalizer Localized in View: @HtmlLocalizer[@text2]
</p>
</div>
}
4.7 执行结果
执行结果如下所示
请注意，我在页脚添加了一些调试信息，以显示 **请求语言 Cookie** 的值，以查看应用程序是否按预期工作。
4.8 IHtmlLocalizer<SharedResource> 的问题
我在使用 IHtmlLocalizer<SharedResource> 时遇到了一些问题。 它解析 strings 并进行翻译，这表明设置是正确的。但是，它对 HTML 不起作用，尽管声称可以。我尝试翻译简单的 HTML，如“<b>Wellcome</b>”，但它不起作用。但是，它对简单的字符串，如“Wellcome”，则有效。
5. 完整代码
由于大多数人都喜欢可以直接复制粘贴的代码，所以这里是应用程序的完整代码。
//Program.cs===========================================================================
namespace SharedResources01
{
public class Program
{
public static void Main(string[] args)
{
//=====Middleware and Services=============================================
var builder = WebApplication.CreateBuilder(args);
//adding multi-language support
AddingMultiLanguageSupportServices(builder);
// Add services to the container.
builder.Services.AddControllersWithViews();
//====App===================================================================
var app = builder.Build();
//adding multi-language support
AddingMultiLanguageSupport(app);
// Configure the HTTP request pipeline.
if (!app.Environment.IsDevelopment())
{
app.UseExceptionHandler("/Home/Error");
}
app.UseStaticFiles();
app.UseRouting();
app.UseAuthorization();
app.MapControllerRoute(
name: "default",
pattern: "{controller=Home}/{action=ChangeLanguage}/{id?}");
app.Run();
}
private static void AddingMultiLanguageSupportServices
(WebApplicationBuilder? builder)
{
if (builder == null) { throw new Exception("builder==null"); };
builder.Services.AddLocalization
(options => options.ResourcesPath = "Resources");
builder.Services.AddMvc()
.AddViewLocalization(LanguageViewLocationExpanderFormat.Suffix);
builder.Services.Configure<RequestLocalizationOptions>(options =>
{
var supportedCultures = new[] { "en", "fr", "de", "it" };
options.SetDefaultCulture(supportedCultures[0])
.AddSupportedCultures(supportedCultures)
.AddSupportedUICultures(supportedCultures);
});
}
private static void AddingMultiLanguageSupport(WebApplication? app)
{
app?.UseRequestLocalization();
}
}
}
//SharedResource.cs===================================================
namespace SharedResources01
{
/*
* This is just a dummy marker class to group shared resources
* We need it for its name and type
*
* It seems the namespace needs to be the same as app root namespace
* which needs to be the same as the assembly name.
* I had some problems when changing the namespace, it would not work.
* If it doesn't work for you, you can try to use full class name
* in your DI instruction, like this one:
* IStringLocalizer<SharedResources01.SharedResource> StringLocalizer
*
* There is no magic in the name "SharedResource", you can
* name it "MyResources" and change all references in the code
* to "MyResources" and all will still work
*
* Location seems can be any folder, although some
* articles claim it needs to be the root project folder
* I do not see such problems in this example.
* To me looks it can be any folder, just keep your
* namespace tidy.
*/
public class SharedResource
{
}
}
//HomeController.cs================================================================
namespace SharedResources01.Controllers
{
public class HomeController : Controller
{
private readonly ILogger<HomeController> _logger;
private readonly IStringLocalizer<SharedResource> _stringLocalizer;
private readonly IHtmlLocalizer<SharedResource> _htmlLocalizer;
/* Here is, of course, the Dependency Injection (DI) coming in and filling
* all the dependencies. The key thing is we are asking for a specific
* type=SharedResource.
* If it doesn't work for you, you can try to use full class name
* in your DI instruction, like this one:
* IStringLocalizer<SharedResources01.SharedResource> stringLocalizer
*/
public HomeController(ILogger<HomeController> logger,
IStringLocalizer<SharedResource> stringLocalizer,
IHtmlLocalizer<SharedResource> htmlLocalizer)
{
_logger = logger;
_stringLocalizer = stringLocalizer;
_htmlLocalizer = htmlLocalizer;
}
public IActionResult ChangeLanguage(ChangeLanguageViewModel model)
{
if (model.IsSubmit)
{
HttpContext myContext = this.HttpContext;
ChangeLanguage_SetCookie(myContext, model.SelectedLanguage);
//doing funny redirect to get new Request Cookie
//for presentation
return LocalRedirect("/Home/ChangeLanguage");
}
//prepare presentation
ChangeLanguage_PreparePresentation(model);
return View(model);
}
private void ChangeLanguage_PreparePresentation(ChangeLanguageViewModel model)
{
model.ListOfLanguages = new List<SelectListItem>
{
new SelectListItem
{
Text = "English",
Value = "en"
},
new SelectListItem
{
Text = "German",
Value = "de",
},
new SelectListItem
{
Text = "French",
Value = "fr"
},
new SelectListItem
{
Text = "Italian",
Value = "it"
}
};
}
private void ChangeLanguage_SetCookie(HttpContext myContext, string? culture)
{
if(culture == null) { throw new Exception("culture == null"); };
//this code sets .AspNetCore.Culture cookie
myContext.Response.Cookies.Append(
CookieRequestCultureProvider.DefaultCookieName,
CookieRequestCultureProvider.MakeCookieValue(new RequestCulture(culture)),
new CookieOptions { Expires = DateTimeOffset.UtcNow.AddMonths(1) }
);
}
public IActionResult LocalizationExample(LocalizationExampleViewModel model)
{
//so, here we use IStringLocalizer
model.IStringLocalizerInController = _stringLocalizer["Wellcome"];
//so, here we use IHtmlLocalizer
model.IHtmlLocalizerInController = _htmlLocalizer["Wellcome"];
return View(model);
}
public IActionResult Error()
{
return View(new ErrorViewModel
{ RequestId = Activity.Current?.Id ?? HttpContext.TraceIdentifier });
}
}
}
//ChangeLanguageViewModel.cs=====================================================
namespace SharedResources01.Models.Home
{
public class ChangeLanguageViewModel
{
//model
public string? SelectedLanguage { get; set; } = "en";
public bool IsSubmit { get; set; } = false;
//view model
public List<SelectListItem>? ListOfLanguages { get; set; }
}
}
//LocalizationExampleViewModel.cs===============================================
namespace SharedResources01.Models.Home
{
public class LocalizationExampleViewModel
{
public string? IStringLocalizerInController { get; set; }
public LocalizedHtmlString? IHtmlLocalizerInController { get; set; }
}
}
@* ChangeLanguage.cshtml ===================================================*@
@model ChangeLanguageViewModel
@{
<div style="width:500px">
<p class="bg-info">
<partial name="_Debug.AspNetCore.CultureCookie" /><br />
</p>
<form id="form1">
<fieldset class="border rounded-3 p-3">
<legend class="float-none w-auto px-3">Change Language</legend>
<div class="form-group">
<label asp-for="SelectedLanguage">Select Language</label>
<select class="form-select" asp-for="SelectedLanguage"
asp-items="@Model.ListOfLanguages">
</select>
<input type="hidden" name="IsSubmit" value="true">
<button type="submit" form="form1"
class="btn btn-primary mt-3 float-end"
asp-area="" asp-controller="Home"
asp-action="ChangeLanguage">
Submit
</button>
</div>
</fieldset>
</form>
</div>
}
@* LocalizationExample.cshtml ====================================================*@
@using Microsoft.AspNetCore.Mvc.Localization
@using Microsoft.Extensions.Localization
@model LocalizationExampleViewModel
@* Here is of course the Dependency Injection (DI) coming in and filling
all the dependencies. The key thing is we are asking for a specific
type=SharedResource.
If it doesn't work for you, you can try to use full class name
in your DI instruction, like this one:
@inject IStringLocalizer<SharedResources01.SharedResource> StringLocalizer
*@
@inject IStringLocalizer<SharedResource> StringLocalizer
@inject IHtmlLocalizer<SharedResource> HtmlLocalizer
@{
<div style="width:600px">
<p class="bg-info">
IStringLocalizer Localized in Controller:
@Model.IStringLocalizerInController
</p>
<p class="bg-info">
@{
string? text1 = StringLocalizer["Wellcome"];
}
IStringLocalizer Localized in View: @text1
</p>
<p class="bg-info">
IHtmlLocalizer Localized in Controller:
@Model.IHtmlLocalizerInController
</p>
<p class="bg-info">
@{
string? text2 = "Wellcome";
}
IHtmlLocalizer Localized in View: @HtmlLocalizer[@text2]
</p>
</div>
}
6. 参考文献
- [1] 使 ASP.NET Core 应用内容可本地化
- [2] 为本地化 ASP.NET Core 应用提供多语言资源
- [3] 实现一个策略，为本地化 ASP.NET Core 应用中的每个请求选择语言/区域性
- [4] ASP.NET Core 中的全球化和本地化
- [5] 疑难解答 ASP.NET Core 本地化
- [6] 借助 SharedResources 进行 ASP.NET Core 本地化
7. 历史
- 2024 年 3 月 6 日：初始版本