我參考這篇https://learn.microsoft.com/zh-tw/aspnet/core/fundamentals/localization?view=aspnetcore-6.0

但是最後輸出的時候都只有輸出名稱不會輸出值

以下是程式碼
Controller的部分

private readonly IStringLocalizer<testController> _localizer;

        public testController(IStringLocalizer<testController> localizer,
            IStringLocalizer<SharedResource> sharedLocalizer)
        {
            _localizer = localizer;
        }

        [HttpGet]
        public string Get()
        {
            return _localizer["test"] + _localizer["test"].Value;
        }

Program的部分只有加上這一部分

builder.Services.AddControllersWithViews();
builder.Services.AddLocalization(options => options.ResourcesPath = "Resources");

builder.Services.AddMvc()
    .AddViewLocalization(LanguageViewLocationExpanderFormat.Suffix)
    .AddDataAnnotationsLocalization();

有人知道我哪裡有寫錯或少加東西嗎....

已解決，詳細參考這篇
https://www.codeproject.com/Articles/5324504/Localization-in-ASP-NET-Core-Web-API