Question

我跟随Linq查询来获取User并添加UserClaimCollection。

public async Task<List<User>> GetCollection()
{
    List<User> result = _identityContext.Users
        .GroupJoin(
            _identityContext.UserClaims,
            u => u.Id,
            uc => uc.UserId,
            (u, uc) => new { user = u, claims = uc })
        .ToList()
        .Select(u => new User(
            new Guid(u.user.Id),
            u.user.UserName,
            u.user.FirstName,
            u.user.LastName,
            u.user.Email,
            new UserClaimCollection(
                u.claims.Select(uc => new UserClaim(uc.ClaimType, uc.ClaimValue)).ToList()
            ))
        ).ToList();

    return result;
}

如何将第二个GroupJoin添加到此选择中以添加角色集合？

例如

public async Task<List<User>> GetCollection()
{
    List<User> result = _identityContext.Users
        .GroupJoin(
            _identityContext.UserClaims,
            u => u.Id,
            uc => uc.UserId,
            (u, uc) => new { user = u, claims = uc })
        .GroupJoin(
            _identityContext.UserRoles,
            u => u.Id,
            ur => ur.UserId,
            (u, ur) => new { user = u, roles= ur })                    
        .ToList()
        .Select(u => new User(
            new Guid(u.user.Id),
            u.user.UserName,
            u.user.FirstName,
            u.user.LastName,
            u.user.Email,
            new UserClaimCollection(
                u.claims.Select(uc => new UserClaim(uc.ClaimType, uc.ClaimValue)).ToList()
            )),
            new UserRoleCollection(
                u.roles.Select(ur => new UserRole(ur.RoleType, ur.RoleValue)).ToList()
            ))
        ).ToList();

    return result;
}

Answer 1

您需要记住第一个GroupJoin的输出是您的新匿名类，因此您就是将其传递给第二个GroupJoin的内容。我建议命名lambda参数以提醒您这一点。

List<User> result = _identityContext.Users
    .GroupJoin(
        _identityContext.UserClaims,
        u => u.Id,
        c => c.UserId,
        (user, claims) => new { user, claims })
    .GroupJoin(
        _identityContext.UserRoles,
        uc => uc.user.Id,
        roles => roles.UserId,
        (uc, roles) => new { uc.user, uc.claims, roles })                    
    .ToList()
    .Select(ucr => new User(
        new Guid(ucr.user.Id),
        ucr.user.UserName,
        ucr.user.FirstName,
        ucr.user.LastName,
        ucr.user.Email,
        new UserClaimCollection(
            ucr.claims.Select(c => new UserClaim(c.ClaimType, c.ClaimValue)).ToList()
        )),
        new UserRoleCollection(
            ucr.roles.Select(r => new UserRole(r.RoleType, r.RoleValue)).ToList()
        ))
    ).ToList();

Linq Group加入多表

1 个答案: