1. 首先，确保在项目中引用了Microsoft.AspNetCore.Localization包。
2. 在程序启动时，添加以下代码：

services.Configure(
    options => {
        var supportedCultures = new List
        {
            new CultureInfo("en-US"),
            new CultureInfo("fr-FR")
            //添加其他语言文化
        };

        options.DefaultRequestCulture = new RequestCulture("en-US");
        options.SupportedCultures = supportedCultures;
        options.SupportedUICultures = supportedCultures;

        //添加CookieRequestCultureProvider
        options.RequestCultureProviders.Insert(0, new CookieRequestCultureProvider());
    });

此代码指定了项目支持的文化信息并添加了CookieRequestCultureProvider。可以根据项目需要添加其他Provider。 3. 在需要使用多语言时，在Controller或视图中添加以下代码:

var currentCulture = HttpContext.Features.Get().RequestCulture.UICulture;

此代码将获取当前用户的语言环境信息，可以将其用于后续处理。

附上完整示例代码： Startup.cs

using Microsoft.AspNetCore.Builder;
using Microsoft.AspNetCore.Hosting;
using Microsoft.Extensions.Configuration;
using Microsoft.Extensions.DependencyInjection;
using Microsoft.Extensions.Hosting;
using Microsoft.AspNetCore.Localization;
using System.Globalization;
using System.Collections.Generic;
using Microsoft.AspNetCore.Localization.Routing;

namespace MvcLocalizationDemo
{
    public class Startup
    {
        public Startup(IConfiguration configuration)
        {
            Configuration = configuration;
        }

        public IConfiguration Configuration { get; }

        // This method gets called by the runtime. Use this method to add services to the container.
        public void ConfigureServices(IServiceCollection services)
        {
            services.AddControllersWithViews();
            services.Configure(
                options => {
                    var supportedCultures = new List
                    {
                        new CultureInfo("en-US"),
                        new CultureInfo("fr-FR")
                    };

                    options.DefaultRequestCulture = new RequestCulture("en-US");
                    options.SupportedCultures = supportedCultures;
                    options.SupportedUICultures = supportedCultures;

                    options.RequestCultureProviders.Insert(0, new RouteData