以下是一个使用ASP.NET Core身份验证实现登录和锁定功能的代码示例：

1. 在Startup.cs文件中配置身份验证服务：

public void ConfigureServices(IServiceCollection services)
{
    services.AddDbContext(options =>
        options.UseSqlServer(Configuration.GetConnectionString("DefaultConnection")));
    
    services.AddIdentity()
        .AddEntityFrameworkStores()
        .AddDefaultTokenProviders();
    
    services.Configure(options =>
    {
        // 配置密码设置
        options.Password.RequireDigit = true;
        options.Password.RequiredLength = 8;
        options.Password.RequireNonAlphanumeric = false;
        options.Password.RequireUppercase = true;
        options.Password.RequireLowercase = false;
        
        // 配置用户锁定设置
        options.Lockout.DefaultLockoutTimeSpan = TimeSpan.FromMinutes(30);
        options.Lockout.MaxFailedAccessAttempts = 5;
        options.Lockout.AllowedForNewUsers = true;
    });

    services.ConfigureApplicationCookie(options =>
    {
        options.LoginPath = "/Account/Login";
        options.LogoutPath = "/Account/Logout";
        options.AccessDeniedPath = "/Account/AccessDenied";
    });

    // 添加授权策略
    services.AddAuthorization(options =>
    {
        options.AddPolicy("RequireAdminRole", policy => policy.RequireRole("Admin"));
        options.AddPolicy("RequireUserRole", policy => policy.RequireRole("User"));
    });

    services.AddControllersWithViews();
}

2. 在AccountController.cs文件中实现登录和锁定功能：

public class AccountController : Controller
{
    private readonly SignInManager _signInManager;
    private readonly UserManager _userManager;

    public AccountController(
        SignInManager signInManager,
        UserManager userManager)
    {
        _signInManager = signInManager;
        _userManager = userManager;
    }

    [HttpGet]
    public IActionResult Login()
    {
        return View();
    }

    [HttpPost]
    public async Task Login(LoginViewModel model, string returnUrl = null)
    {
        if (ModelState.IsValid)
        {
            var result = await _signInManager.PasswordSignInAsync(model.Email, model.Password, model.RememberMe, lockoutOnFailure: false);
            
            if (result.Succeeded)
            {
                return RedirectToAction("Index", "Home");
            }
            
            if (result.IsLockedOut)
            {
                // 用户被锁定，显示错误消息
                ModelState.AddModelError(string.Empty, "账户被锁定，请稍后再试！");
                return View(model);
            }
            
            ModelState.AddModelError(string.Empty, "无效的登录尝试！");
            return View(model);
        }
        
        return View(model);
    }

    [HttpPost]
    public async Task Logout()
    {
        await _signInManager.SignOutAsync();
        return RedirectToAction("Index", "Home");
    }
}

3. 在AccountController.cs文件中实现锁定用户功能：

public class AccountController : Controller
{
    // ...

    [HttpPost]
    [ValidateAntiForgeryToken]
    public async Task LockUser(string userId)
    {
        var user = await _userManager.FindByIdAsync(userId);
        
        if (user != null)
        {
            await _userManager.SetLockoutEndDateAsync(user, DateTimeOffset.UtcNow.AddYears(100));
            // 或使用以下代码立即锁定用户
            // await _userManager.SetLockoutEnabledAsync(user, true);
            // await _userManager.SetLockoutEndDateAsync(user, DateTimeOffset.MaxValue);
        }
        
        return RedirectToAction("Index", "Home");
    }

    [HttpPost]
    [ValidateAntiForgeryToken]
    public async Task UnlockUser(string userId)
    {
        var user = await _userManager.FindByIdAsync(userId);
        
        if (user != null)
        {
            await _userManager.SetLockoutEndDateAsync(user, null);
            // 或使用以下代码立即解锁用户
            // await _userManager.SetLockoutEnabledAsync(user, false);
        }
        
        return RedirectToAction("Index", "Home");
    }
}

以上代码示例演示了如何配置ASP.NET Core身份验证服务，并在AccountController中实现登录和锁定功能。您可以根据自己的需求进行修改和扩展。