.NET Core/Entity Framework Core中从UserRoles表提取自定义字段的实现咨询

嗨，看起来你已经完成了EF Core Identity模型的自定义，给UserRole关联关系添加了自定义字段，现在想要在用户登录后提取这些字段并传递给应用对吧？我来帮你梳理下实现步骤：

首先先把你给出的自定义实体类补全并整理好：

public class ApplicationUser: IdentityUser
{
    public virtual ICollection<ApplicationUserRole> UserRoles { get; set; } = null!;
    public string? UserCode { get; set; }
    public string? UserExternalCode1 { get; set; }
    public string? UserExternalCode2 { get; set; }
    public string? UserExternalCode3 { get; set; }
    public Guid? EmployeeTypeId { get; set; }
    public EmployeeType? EmployeeType { get; set; } = null!;
}

public class ApplicationUserRole: IdentityUserRole<string>
{
    public Guid? LineId { get; set; }
    public Line? Line { get; set; } = null!;
    public Guid? TerritoryId { get; set; }
    public Territory? Territory { get; set; } = null!;
}

接下来是关键的配置和提取步骤：

1. 确保DbContext正确配置自定义UserRole实体 #

首先要在你的ApplicationDbContext里注册ApplicationUserRole，并且配置好它的复合主键（因为IdentityUserRole<TKey>默认是UserId+RoleId的复合主键），同时配置导航属性的关联：

public class ApplicationDbContext : IdentityDbContext<ApplicationUser, IdentityRole<string>, string, IdentityUserClaim<string>,
    ApplicationUserRole, IdentityUserLogin<string>, IdentityRoleClaim<string>, IdentityUserToken<string>>
{
    public DbSet<ApplicationUserRole> ApplicationUserRoles { get; set; }
    public DbSet<Line> Lines { get; set; }
    public DbSet<Territory> Territories { get; set; }
    public DbSet<EmployeeType> EmployeeTypes { get; set; }

    public ApplicationDbContext(DbContextOptions<ApplicationDbContext> options)
        : base(options)
    {
    }

    protected override void OnModelCreating(ModelBuilder builder)
    {
        base.OnModelCreating(builder);

        // 配置ApplicationUserRole的复合主键
        builder.Entity<ApplicationUserRole>(ur =>
        {
            ur.HasKey(r => new { r.UserId, r.RoleId });
            
            // 配置与Line的关联
            ur.HasOne(ur => ur.Line)
              .WithMany()
              .HasForeignKey(ur => ur.LineId)
              .OnDelete(DeleteBehavior.Restrict);

            // 配置与Territory的关联
            ur.HasOne(ur => ur.Territory)
              .WithMany()
              .HasForeignKey(ur => ur.TerritoryId)
              .OnDelete(DeleteBehavior.Restrict);
        });
    }
}

2. 用户登录后提取自定义UserRole字段 #

当用户登录成功后，你可以通过UserManager获取用户对象，并且显式Include自定义的UserRoles集合以及关联的实体，这样就能拿到那些自定义字段了：

方式一：使用UserManager获取用户并包含关联数据 #

private readonly UserManager<ApplicationUser> _userManager;
private readonly IHttpContextAccessor _httpContextAccessor;

public YourService(UserManager<ApplicationUser> userManager, IHttpContextAccessor httpContextAccessor)
{
    _userManager = userManager;
    _httpContextAccessor = httpContextAccessor;
}

public async Task<List<ApplicationUserRole>> GetUserCustomRoleData()
{
    var currentUser = await _userManager.GetUserAsync(_httpContextAccessor.HttpContext.User);
    if (currentUser == null)
    {
        throw new UnauthorizedAccessException("用户未登录");
    }

    // 显式加载UserRoles以及关联的Line和Territory
    await _userManager.Context.Entry(currentUser)
        .Collection(u => u.UserRoles)
        .Query()
        .Include(ur => ur.Line)
        .Include(ur => ur.Territory)
        .LoadAsync();

    // 现在currentUser.UserRoles里就包含了所有自定义字段和关联实体
    return currentUser.UserRoles.ToList();
}

方式二：直接通过DbContext查询 #

如果你更倾向于直接查询数据库，也可以这样做：

public async Task<List<ApplicationUserRole>> GetUserCustomRoleData(string userId)
{
    return await _dbContext.ApplicationUserRoles
        .Include(ur => ur.Line)
        .Include(ur => ur.Territory)
        .Where(ur => ur.UserId == userId)
        .ToListAsync();
}

3. 将自定义字段传递给应用的建议 #

如果需要在整个应用中都能便捷访问这些字段，可以考虑在用户登录时把关键的自定义字段添加到Claims中，这样后续可以通过User.Claims直接获取：

// 在登录逻辑中（比如Login方法）
var user = await _userManager.FindByEmailAsync(model.Email);
var userRoles = await _dbContext.ApplicationUserRoles
    .Include(ur => ur.Line)
    .Where(ur => ur.UserId == user.Id)
    .ToListAsync();

var claims = new List<Claim>
{
    new Claim(ClaimTypes.NameIdentifier, user.Id),
    // 添加自定义字段到Claims
    new Claim("LineId", userRoles.FirstOrDefault()?.LineId.ToString() ?? string.Empty),
    new Claim("TerritoryName", userRoles.FirstOrDefault()?.Territory?.Name ?? string.Empty)
};

// 创建ClaimsIdentity并完成登录
var claimsIdentity = new ClaimsIdentity(claims, CookieAuthenticationDefaults.AuthenticationScheme);
await HttpContext.SignInAsync(CookieAuthenticationDefaults.AuthenticationScheme, new ClaimsPrincipal(claimsIdentity));

这样之后，在任何需要的地方都可以通过User.FindFirstValue("LineId")来获取对应的自定义字段值了。

备注：内容来源于stack exchange，提问作者stefano