ASP.NET Core MVC 之語系切換

1. 新增專案類型：ASP.NET Core Web應用程式
   
2. 目標Framework為.NET 7.0
3. 在Program.cs裡的內加進如下:

var supportedCultures = new List<CultureInfo>()
{
    CultureInfo.GetCultureInfo("en"),
    CultureInfo.GetCultureInfo("zh")
};

app.UseRequestLocalization(new RequestLocalizationOptions()
{
    DefaultRequestCulture = new RequestCulture("zh"),
    SupportedCultures = supportedCultures,
    SupportedUICultures = supportedCultures,
});

其中DefaultRequestCulture = new RequestCulture("zh")為預設中文
4.在專案下新增資料夾Resources並新增SharedResources.cs,SharedResources.en和SharedResources.zh的resx資源檔

SharedResources.cs

namespace Localization
{
    public class SharedResources
    {
    }
}

5.編輯resx的中英文如下：

6.在 _Layout.cshtm 新增如下：

<!-- 自己弄的選取語言下拉選單 -->
<select id="selectLang">
    <option value="zh">中文</option>
    <option value="en">English</option>
</select>

$(function () {
    dropdownListSetLanguage();
    $("#selectLang").on("change", function () {
        changeLanguage();
    });
})

 /** 下拉選單選取的語系 */
 function dropdownListSetLanguage() {

     const urlParams = new URLSearchParams(window.location.search);
     var param = urlParams.get('culture')
     if (param !== null) {
         $("#selectLang").val(param)
     } else {
         var culture = $.cookie('culture');
         $("#selectLang").val(culture)
     }
 }

 /** 變更語系*/
 function changeLanguage() {
     var selectedLang = $("#selectLang").val();

     const urlParams = new URLSearchParams(window.location.search);
     var param = urlParams.get('culture')
     var pathName = $(location).attr('pathname');

     console.log('changeLanguage urlParams:' + urlParams)
     console.log('changeLanguage param:' + param)
     console.log('changeLanguage pathname:' + pathName)

     var url = pathName + "?culture=" + selectedLang;
     window.location.href = url;
 }

7.在Razor套用語系的寫法：

• 第一種
  HomeController.cs

  public IActionResult Index(string culture)
  {
    ViewData["Login"] = _localizer["Login"];
    return View();
  }
  

  Index.cshtml

  <h5>@ViewData["Login"]</h5>
  

• 第二種
  Index.cshtml

  @using Microsoft.AspNetCore.Mvc.Localization
  @using Localization
  @inject IHtmlLocalizer<SharedResources> _localizer
  

  <h5>@_localizer["lang"]</h5>
  

  畫面結果如下：