使用ASP.net在Restful API中显示多对多

public class User
{
    public int UserId { get; set; }
    public string UserName { get; set; }
    public ICollection<Role> Roles { get; set; }
}

public class Role
{
    public int RoleId { get; set; }
    public string RoleName { get; set; }
    public ICollection<User> Users { get; set; }
}

public class YourDbContext : DbContext
{
    public DbSet<User> Users { get; set; }
    public DbSet<Role> Roles { get; set; }

    protected override void OnModelCreating(ModelBuilder modelBuilder)
    {
        modelBuilder.Entity<User>()
            .HasMany(u => u.Roles)
            .WithMany(r => r.Users)
            .UsingEntity(j => j.ToTable("UserRole"));
    }
}

[Route("api/users")]
[ApiController]
public class UsersController : ControllerBase
{
    private readonly YourDbContext _context;

    public UsersController(YourDbContext context)
    {
        _context = context;
    }

    [HttpGet("{userId}/roles")]
    public IActionResult GetUserRoles(int userId)
    {
        var user = _context.Users.Include(u => u.Roles).FirstOrDefault(u => u.UserId == userId);
        if (user == null)
        {
            return NotFound();
        }
        return Ok(user.Roles);
    }

    [HttpGet("{roleId}/users")]
    public IActionResult GetRoleUsers(int roleId)
    {
        var role = _context.Roles.Include(r => r.Users).FirstOrDefault(r => r.RoleId == roleId);
        if (role == null)
        {
            return NotFound();
        }
        return Ok(role.Users);
    }
}

public class Startup
{
    // ...

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

        services.AddControllers();
    }

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

        app.UseRouting();

        app.UseEndpoints(endpoints =>
        {
            endpoints.MapControllers();
        });
    }
}