1. 在 ASP.NET Core MVC 中使用 FluentValidation 库来验证电话号码和社会安全号码的唯一性。首先，在项目中安装 FluentValidation 库，并使用其 NuGet 包管理器控制台来执行以下命令：

Install-Package FluentValidation.AspNetCore

2. 创建一个新的类来验证电话号码和社会安全号码的唯一性。以下是一个例子：

using FluentValidation;
using Microsoft.EntityFrameworkCore;
using System.Threading;
using System.Threading.Tasks;

public class UserValidator : AbstractValidator
{
    private readonly ApplicationDbContext _dbContext;

    public UserValidator(ApplicationDbContext dbContext)
    {
        _dbContext = dbContext;

        RuleFor(x => x.PhoneNumber).MustAsync(BeUniquePhoneNumber).WithMessage("该电话号码已经被使用");
        RuleFor(x => x.SSN).MustAsync(BeUniqueSSN).WithMessage("该社会安全号码已经被使用");
    }

    private async Task BeUniquePhoneNumber(User user, string phoneNumber, CancellationToken cancellationToken)
    {
        return await _dbContext.Users.AllAsync(x => x.Id == user.Id || x.PhoneNumber != phoneNumber, cancellationToken);
    }

    private async Task BeUniqueSSN(User user, string ssn, CancellationToken cancellationToken)
    {
        return await _dbContext.Users.AllAsync(x => x.Id == user.Id || x.SSN != ssn, cancellationToken);
    }
}

3. 在 Startup.cs 文件中配置 FluentValidation：

using FluentValidation.AspNetCore;

public void ConfigureServices(IServiceCollection services)
{
    services.AddDbContext(options =>
        options.UseSqlServer(Configuration.GetConnectionString("DefaultConnection")));

    services.AddControllersWithViews()
        .AddFluentValidation(fv => fv.RegisterValidatorsFromAssemblyContaining());
}

4. 在模型类中使用 UserValidator 来验证电话号码和社会安全号码的唯一性。例如：

public class User
{
    public int Id { get; set; }
    public string Name { get; set; }
    public string PhoneNumber { get; set; }
    public string SSN { get