将我的应用程序迁移到 ASP.NET Core 3.0 后，之前有效的索引 URL returns 404

Question

一个应用程序从 ASP.NET Core 2.0（我认为）开始，然后迁移到 2.1，然后迁移到 2.2，现在我正在尝试将它迁移到 3.0 但失败了...

我阅读并尝试应用 official migration docs 中的说明，据此我应该（除其他外）将 services.AddMvc() 替换为 services.AddRazorPages() 并将 app.UseMvc() 替换为app.UseEndpoints(endpoints => {endpoints.MapRazorPages();}) 如果我使用的是 Razor Pages。据我所知，我一直在使用 Razor Pages 而不是成熟的 MVC，所以这就是我所做的。

现在以前工作的 URL return HTTP 404 而不是任何内容...

例如，/ 或 /Index 路由会执行此操作，即使在项目目录中有一个 Pages/Index.cshtml 文件和一个 Pages/Index.cshtml.cs 文件。（尽管很奇怪：也许只有索引 url 失败了 - 我只是尝试将浏览器指向 /Error 并且它起作用了！）

Pages/Index.cshtml.cs 内容（与工作版本相同）：

using System;
using System.Collections.Generic;
using System.Linq;
using System.Threading.Tasks;
using System.Web;
using Microsoft.AspNetCore.Mvc;
using Microsoft.AspNetCore.Mvc.RazorPages;
using Mon.Battle;

namespace mon.Pages
{
    public class IndexModel : PageModel
    {
        public IndexModel(IBattleManager battleManager)
        {
            // I hope I don't have to lock this dict here, I'm only reading
            configurationSerialized = battleManager.configurationSerialized;
        }

        public ConfigurationSerializedFormat configurationSerialized;

        public void OnGet()
        {

        }
    }
}

Pages/Index.cshtml也有一些内容，但是太长太乱了post这里就整体...不过肯定是return什么的是 return在迁移到 3.0 之前正在做一些事情。

Index.cshtml 顶部的页面指令足够短，但是：

@* TODO: The site becomes ugly :( Should I start using Bootstrap, instead of trying to handcraft CSS? *@
@* Hey... I actually start to like how the site looks :) *@

@page

@using System.Text.Encodings.Web
@using Microsoft.Extensions.Configuration
@inject JavaScriptEncoder jsencoder
@inject IConfiguration conf
@using static System.Text.Json.JsonSerializer
@model IndexModel
@{
    Layout = null;
}

不幸的是，这些必须与迁移前的版本稍作更改：即自从 3.0 删除 Newtonsoft.JSON，我不得不将其替换为 System.Text.Json。

我当前的 Startup.cs（我想我准确地应用了上述文档中的说明）：

using System;
using System.Collections.Generic;
using System.Linq;
using System.Threading.Tasks;
using Microsoft.AspNetCore.Builder;
using Microsoft.AspNetCore.Identity;
using Microsoft.AspNetCore.Hosting;
using Microsoft.AspNetCore.Http;
using Microsoft.AspNetCore.HttpsPolicy;
using Microsoft.EntityFrameworkCore;
using mon.Data;
using Microsoft.Extensions.Configuration;
using Microsoft.Extensions.DependencyInjection;
using Microsoft.Extensions.Hosting;
using Mon.Chat;
using Mon.MatchMaker;
using Mon.Battle;
using Mon.Player;

namespace mon
{
    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.Configure<CookiePolicyOptions>(options =>
            {
                // This lambda determines whether user consent for non-essential cookies is needed for a given request.
                options.CheckConsentNeeded = context => true;
                options.MinimumSameSitePolicy = SameSiteMode.None;
            });

            services.Configure<IdentityOptions>(options =>
            {
                options.User.AllowedUserNameCharacters = "abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ0123456789";
            });

            services.AddDbContext<ApplicationDbContext>(options =>
                options.UseSqlServer(
                    Configuration.GetConnectionString("DefaultConnection")));
            services.AddDefaultIdentity<ApplicationUser>().AddRoles<IdentityRole>()
                .AddEntityFrameworkStores<ApplicationDbContext>();

            services.AddRazorPages();

            services.AddSignalR();

            services.AddSingleton<IBattleManager, BattleManager>();
        }

        // This method gets called by the runtime. Use this method to configure the HTTP request pipeline.
        public void Configure(IApplicationBuilder app, IWebHostEnvironment env)
        {
            if (env.IsDevelopment())
            {
                app.UseDeveloperExceptionPage();
                app.UseDatabaseErrorPage();
            }
            else
            {
                app.UseExceptionHandler("/Error");
                app.UseHsts();
            }

            app.UseHttpsRedirection();
            app.UseStaticFiles();
            app.UseRouting();

            app.UseAuthentication();

            app.UseEndpoints(endpoints =>
            {
                endpoints.MapHub<ChatHub>("/chathub");
                endpoints.MapHub<MatchMakerHub>("/mmrhub");
                endpoints.MapHub<BattleHub>("/battlehub");
                endpoints.MapRazorPages();
            });
        }
    }
}

上一个 Startup.cs:

using System;
using System.Collections.Generic;
using System.Linq;
using System.Threading.Tasks;
using Microsoft.AspNetCore.Builder;
using Microsoft.AspNetCore.Identity;
using Microsoft.AspNetCore.Hosting;
using Microsoft.AspNetCore.Http;
using Microsoft.AspNetCore.HttpsPolicy;
using Microsoft.AspNetCore.Mvc;
using Microsoft.EntityFrameworkCore;
using mon.Data;
using Microsoft.Extensions.Configuration;
using Microsoft.Extensions.DependencyInjection;
using Mon.Chat;
using Mon.MatchMaker;
using Mon.Battle;
using Newtonsoft.Json.Serialization;
using Mon.Player;

namespace mon
{
    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.Configure<CookiePolicyOptions>(options =>
            {
                // This lambda determines whether user consent for non-essential cookies is needed for a given request.
                options.CheckConsentNeeded = context => true;
                options.MinimumSameSitePolicy = SameSiteMode.None;
            });

            services.Configure<IdentityOptions>(options =>
            {
                options.User.AllowedUserNameCharacters = "abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ0123456789";
            });

            services.AddDbContext<ApplicationDbContext>(options =>
                options.UseSqlServer(
                    Configuration.GetConnectionString("DefaultConnection")));
            services.AddDefaultIdentity<ApplicationUser>().AddRoles<IdentityRole>()
                .AddEntityFrameworkStores<ApplicationDbContext>();

            services.AddMvc().SetCompatibilityVersion(CompatibilityVersion.Version_2_2);

            services
                .AddSignalR()
                .AddJsonProtocol(options =>
                {
                    options.PayloadSerializerSettings.ContractResolver = new DefaultContractResolver();
                });

            services.AddSingleton<IBattleManager, BattleManager>();
        }

        // This method gets called by the runtime. Use this method to configure the HTTP request pipeline.
        public void Configure(IApplicationBuilder app, IHostingEnvironment env)
        {
            if (env.IsDevelopment())
            {
                app.UseDeveloperExceptionPage();
                app.UseDatabaseErrorPage();
            }
            else
            {
                app.UseExceptionHandler("/Error");
                app.UseHsts();
            }

            app.UseHttpsRedirection();
            app.UseStaticFiles();
            app.UseCookiePolicy();

            app.UseAuthentication();

            app.UseSignalR(routes =>
            {
                routes.MapHub<ChatHub>("/chathub");
                routes.MapHub<MatchMakerHub>("/mmrhub");
                routes.MapHub<BattleHub>("/battlehub");
            });

            app.UseMvc();
        }
    }
}

我做错了什么？我错过了什么？为什么 /Index return HTTP 404？

如果您需要更多信息，我会提供。

Answer 1

有一次我的 .csproj 文件出现问题。确保您的文件没有像这样列出：

<ItemGroup>
   <Content Remove="Views\Extractor\Insert.cshtml" />
   <Content Remove="Views\_ViewImports.cshtml" />
</ItemGroup>

当我们复制粘贴文件/更改构建操作等时可能会发生这种情况

将我的应用程序迁移到 ASP.NET Core 3.0 后，之前有效的索引 URL returns 404

After migrating my app to ASP.NET Core 3.0, the previously valid Index URL returns 404

c#

url-routing

asp.net-core

razor-pages