1、在Startup类的Configure方法，添加身份验证的中间件AuthenticationMiddleware
app.UseAuthentication();
2、在Startup类的ConfigureServices方法，添加Cookie验证的服务，使用Cookies验证体系，
CookieAuthenticationDefaults.AuthenticationScheme="Cookies"
?services.AddAuthentication(CookieAuthenticationDefaults.AuthenticationScheme) ???????????????.AddCookie(CookieAuthenticationDefaults.AuthenticationScheme, options => ???????????????{ ???????????????????options.AccessDeniedPath = "/Sys/Home/Index"; ???????????????????options.LoginPath = "/Sys/Home/Login"; ???????????????????options.Cookie.Name = "AuthCookie"; ???????????????????options.Cookie.Path = "/"; ???????????????????options.Cookie.Expiration = TimeSpan.FromMinutes(30); ???????????????});3、添加登录action，ClaimsIdentity(string authenticationType)的authenticationType必须和service设置的验证体系一样，才能正常验证，
[HttpPost] ???????[AllowAnonymous] ???????public async Task<ActionResult> Login() ???????{ ???????????string AdminAccount = Request.Form["AdminAccount"]; ???????????string Password = Request.Form["Password"]; ???????????if (string.IsNullOrWhiteSpace(AdminAccount)) ???????????{ ???????????????return JsonError("账号不能为空"); ???????????} ???????????if (string.IsNullOrWhiteSpace(Password)) ???????????{ ???????????????return JsonError("密码不能为空"); ???????????} ???????????Admin admin = _context.Admins.FirstOrDefault(c => c.AdminAccount == AdminAccount && c.Password == Password); ???????????if (admin == null) ???????????{ ???????????????return JsonError("用户名或者密码错误"); ???????????} ???????????ClaimsIdentity identity = new ClaimsIdentity(CookieAuthenticationDefaults.AuthenticationScheme); ???????????identity.AddClaim(new Claim(ClaimTypes.Name, admin.Id.ToString())); ???????????await HttpContext.SignInAsync(new ClaimsPrincipal(identity)); ???????????return JsonSuccess(); ???????}4、在需要验证的控制器上加[AuthorizeAttribute]特性，通过HttpContext.User.Identity.IsAuthenticated可判断用户是否已通过验证
5、退出登录Action
/// <summary> ???????/// 退出登录 ???????/// </summary> ???????/// <returns></returns> ???????public async Task<ActionResult> SignOut() ???????{ ???????????await HttpContext.SignOutAsync(CookieAuthenticationDefaults.AuthenticationScheme); ???????????return JsonSuccess(); ???????}AspNetCore2身份验证
原文地址：https://www.cnblogs.com/tangchun/p/8716715.html