1、新建Asp.Net Core Web MVC專案

2、專案目錄結構

3、修改launchSettings.json

{
 
  "profiles": {
   
    "WebApplication1": {
      "commandName": "Project",
      "dotnetRunMessages": "true",
      "launchBrowser": true,
      "applicationUrl": "http://localhost:5000",
      "environmentVariables": {
        "ASPNETCORE_ENVIRONMENT
 
": "Development"
      }
    }
  }
}

4、新增User.cs

  public class User
    {
        public string Name { get; set; }


        public string Password { get; set; }
    }

5、新增UserServer.cs

   public class UserServer
    {
        private List<User> users;
        public List<User> Users 
        {
            
 
get { return users; }
        }

        public UserServer()
        {
            users = new List<User>()
            {
             new User(){ Name="qqqq",Password="123"},
              new User(){ Name="wwww",Password="123"},
               new User(){ Name="eeee",Password="123"},
                
 
new User(){ Name="rrrr",Password="123"},
            };
        }

    }

6、Views資料夾下新增Login資料夾，新增Index.cshtml，Deny.cshtml

@{
    ViewData["Title"] = "登入頁面";
}


<div>
    請登入！
</div>

@using (Html.BeginForm("Login", "Login", FormMethod.Post))
{
    <div>
        <label> 使用者名稱：</label>
        <input name="UserName" type="text" placeholder="請輸入使用者名稱" />
    </div>
    <div>
        <label>密碼：</label>
        <input name="Password" type="password" />
    </div>
    <div>
        <input type="submit" value="登入" />
    </div>
}
<div>
    @ViewBag.Msg
</div>

@{ 
    ViewData["Title"] = "未授權";
}

<div>
    未授權
</div>

7、新增LoginController.cs

  public class LoginController : Controller
    {
        UserServer userServer = new UserServer();
        public IActionResult Index()
        {
            return View();
        }

        public async Task<IActionResult> Login()
        {
            var userName = Request.Form["UserName"];
            var password = Request.Form["Password"];
            var item = userServer.Users.Find(_ => _.Name == userName);
            if (item != null && password == item.Password)
            {
                //用Claim來構造一個ClaimsIdentity，然後呼叫 SignInAsync 方法。
                var claims = new List<Claim>();
                claims.Add(new Claim(ClaimTypes.Name, userName));
                var claimsIdentity = new ClaimsIdentity(claims, "myCookies");
                //登入
                await HttpContext.SignInAsync("myCookies", new ClaimsPrincipal(claimsIdentity));
                return RedirectToAction("Privacy", "Home");
            }
            else
                ViewBag.Msg = "登陸失敗";
            return View("Index");
        }
        public async Task<IActionResult> Logout()
        {
            //退出
            await HttpContext.SignOutAsync("myCookies");
            return RedirectToAction("Index", "Home");

        }

        public IActionResult Deny()
        {
            return View();
        }
    }

8、修改_Layout.cshtml

   <div class="navbar-collapse collapse d-sm-inline-flex justify-content-between">
                    <ul class="navbar-nav flex-grow-1">
                        <li class="nav-item">
                            <a class="nav-link text-dark" asp-area="" asp-controller="Home" asp-action="Index">Home</a>
                        </li>
                        <li class="nav-item">
                            <a class="nav-link text-dark" asp-area="" asp-controller="Home" asp-action="Privacy">Privacy</a>
                        </li>
                        @if (User.Identity.IsAuthenticated)
                        {
                        <li class="nav-item">
                            <a class="nav-link text-dark" asp-area="" asp-controller="Login" asp-action="Logout">退出</a>
                        </li>
                        }
                    </ul>
                </div>

9、修改Startup.cs

public class Startup
    {
        private const string cookieScheme = "myCookies";
        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.AddAuthentication(cookieScheme)
        .AddCookie(cookieScheme, option =>
        {
            option.LoginPath = new PathString("/login/index");
            option.AccessDeniedPath = new PathString("/login/deny");
        });
        }

        // 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();
            }
            else
            {
                app.UseExceptionHandler("/Home/Error");
            }
            app.UseStaticFiles();

            app.UseRouting();

            app.UseAuthentication();

            app.UseAuthorization();

            app.UseEndpoints(endpoints =>
            {
                endpoints.MapControllerRoute(
                    name: "default",
                    pattern: "{controller=Home}/{action=Index}/{id?}");
            });
        }
    }