在ASP.NET核心MVC中使用EF核心查询获取可为空的关系字段

public class User
{
    public int Id { get; set; }
    public string Name { get; set; }
    public int? AddressId { get; set; }
    public Address Address { get; set; }
}

public class Address
{
    public int Id { get; set; }
    public string Street { get; set; }
    public string City { get; set; }
}

public class ApplicationDbContext : DbContext
{
    public DbSet<User> Users { get; set; }
    public DbSet<Address> Addresses { get; set; }

    protected override void OnConfiguring(DbContextOptionsBuilder optionsBuilder)
    {
        optionsBuilder.UseSqlServer("YourConnectionString");
    }
}

public class UserController : Controller
{
    private readonly ApplicationDbContext _context;

    public UserController(ApplicationDbContext context)
    {
        _context = context;
    }

    public IActionResult Index()
    {
        var users = _context.Users.Include(u => u.Address).ToList();
        return View(users);
    }
}

@model List<User>

@foreach (var user in Model)
{
    <h3>@user.Name</h3>
    @if (user.Address != null)
    {
        <p>@user.Address.Street</p>
        <p>@user.Address.City</p>
    }
    else
    {
        <p>No address available</p>
    }
}