以下是使用ASP.NET Core自定义身份验证和授权的解决方法，包含了代码示例：

1. 创建一个ASP.NET Core项目：

dotnet new web -o CustomAuthExample
cd CustomAuthExample

2. 添加所需的NuGet包：

dotnet add package Microsoft.AspNetCore.Authentication

3. 在Startup.cs文件中配置身份验证和授权：

using Microsoft.AspNetCore.Authentication;
using Microsoft.AspNetCore.Authorization;
using Microsoft.AspNetCore.Builder;
using Microsoft.AspNetCore.Hosting;
using Microsoft.AspNetCore.Http;
using Microsoft.Extensions.DependencyInjection;
using Microsoft.Extensions.Hosting;

namespace CustomAuthExample
{
    public class Startup
    {
        public void ConfigureServices(IServiceCollection services)
        {
            services.AddAuthentication("CustomAuthentication")
                .AddScheme("CustomAuthentication", null);

            services.AddAuthorization(options =>
            {
                options.AddPolicy("CustomPolicy", policy =>
                {
                    policy.Requirements.Add(new CustomRequirement());
                });
            });

            services.AddSingleton();

            services.AddControllersWithViews();
        }

        public void Configure(IApplicationBuilder app, IWebHostEnvironment env)
        {
            app.UseRouting();

            app.UseAuthentication();
            app.UseAuthorization();

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

4. 创建一个自定义认证处理程序CustomAuthenticationHandler.cs：

using System.Security.Claims;
using System.Text.Encodings.Web;
using System.Threading.Tasks;
using Microsoft.AspNetCore.Authentication;
using Microsoft.Extensions.Logging;
using Microsoft.Extensions.Options;

namespace CustomAuthExample
{
    public class CustomAuthenticationHandler : AuthenticationHandler
    {
        public CustomAuthenticationHandler(IOptionsMonitor options, ILoggerFactory logger, UrlEncoder encoder, ISystemClock clock) : base(options, logger, encoder, clock)
        {
        }

        protected override async Task HandleAuthenticateAsync()
        {
            // 在此处编写自定义身份验证逻辑
            // 如果验证成功，可以使用以下代码创建用户声明
            var claims = new[] {
                new Claim(ClaimTypes.NameIdentifier, "1"),
                new Claim(ClaimTypes.Name, "John Doe"),
            };

            var identity = new ClaimsIdentity(claims, Scheme.Name);
            var principal = new ClaimsPrincipal(identity);
            var ticket = new AuthenticationTicket(principal, Scheme.Name);

            return await Task.FromResult(AuthenticateResult.Success(ticket));
        }
    }
}

5. 创建自定义要求类CustomRequirement.cs：

using Microsoft.AspNetCore.Authorization;

namespace CustomAuthExample
{
    public class CustomRequirement : IAuthorizationRequirement
    {
    }
}

6. 创建自定义要求处理程序CustomRequirementHandler.cs：

using System.Threading.Tasks;
using Microsoft.AspNetCore.Authorization;

namespace CustomAuthExample
{
    public class CustomRequirementHandler : AuthorizationHandler
    {
        protected override Task HandleRequirementAsync(AuthorizationHandlerContext context, CustomRequirement requirement)
        {
            // 在此处编写自定义授权逻辑
            // 可以使用context.Succeed(requirement)来授权通过，或者使用context.Fail()来拒绝授权

            return Task.CompletedTask;
        }
    }
}

现在，您可以在控制器或Action方法上使用[Authorize]属性来限制访问：

[Authorize(Policy = "CustomPolicy")]
public IActionResult MySecureAction()
{
    return View();
}

这就是使用ASP.NET Core自定义身份验证和授权的解决方法，包含了代码示例。您可以根据自己的需求进行修改和扩展。