在ASP.NET Core 7.0中启用本地化需要进行以下步骤：

1.在Startup.cs文件中添加以下代码：

using Microsoft.AspNetCore.Localization;
using System.Globalization;

public void ConfigureServices(IServiceCollection services)
{
    services.AddLocalization(options => options.ResourcesPath = "Resources");
    services.Configure(options =>
    {
        var supportedCultures = new[]
        {
            new CultureInfo("en-US"),
            new CultureInfo("es-ES"),
            new CultureInfo("zh-CN"),
        };

        options.DefaultRequestCulture = new RequestCulture(culture: "en-US", uiCulture: "en-US");
        options.SupportedCultures = supportedCultures;
        options.SupportedUICultures = supportedCultures;
    });
}

public void Configure(IApplicationBuilder app, IWebHostEnvironment env)
{
    var supportedCultures = new[]
    {
        new CultureInfo("en-US"),
        new CultureInfo("es-ES"),
        new CultureInfo("zh-CN"),
    };

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

2.在Controllers文件夹中创建一个控制器，并使用IStringLocalizer作为依赖注入。

例如，我们可以创建一个名为HomeController的控制器如下：

using System.Diagnostics;
using Microsoft.AspNetCore.Mvc;
using Microsoft.Extensions.Localization;
using Localized.Models;

namespace Localized.Controllers
{
    public class HomeController : Controller
    {
        private readonly IStringLocalizer _localizer;

        public HomeController(IStringLocalizer localizer)
        {
            _localizer = localizer;
        }

        public IActionResult Index()
        {
            ViewData["HelloMessage"] = _localizer["HelloMessage"];

            return View();
        }
    }
}

3.在Resources文件夹中创建一个名为Shared.resx的文件，并添加资源，例如：

键：HelloMessage

值（英文版）：Hello, World!

值（西班牙文版）：`¡Hola