Linq adding items to list in the query - linq

Question

Good day,
I have one problem. I have three Domain objects
public class User
{
public Guid Id { get; set; }
public string Username { get; set; }
public string EmailAddress { get; set; }
public string Password { get; set; }
public string FirstName { get; set; }
public string LastName { get; set; }
[NotMapped]
public List<string> Roles { get; set; }
//nav prop
public List<User_Role> UserRoles { get; set; }
}
public class User_Role
{
public Guid Id { get; set; }
public Guid UserId { get; set; }
//nav prop
public User User { get; set; }
public Guid RoleId { get; set; }
//nav prop
public Role Role { get; set; }
}
public class Role
{
public Guid Id { get; set; }
public string Name { get; set; }
public List<User_Role> UserRoles { get; set; }
}
I want to create DTO object from them
public class ReturnUserDto
{
public Guid Id { get; set; }
public string Username { get; set; }
public string EmailAddress { get; set; }
public string Password { get; set; }
public string FirstName { get; set; }
public string LastName { get; set; }
public List<string> Roles { get; set; }
}
I have created a controller for it
[Route("api/[controller]")]
[ApiController]
public class UserController : ControllerBase
{
public readonly IUserRepository _userRepository;
public readonly IRoleRepository _roleRepository;
public readonly IUserRoleRepository _userRoleRepository
public UserController(IUserRepository userRepository, IRoleRepository IRoleRepository,
IUserRoleRepository userRoleRepository)
{
_userRepository = userRepository;
_roleRepository = IRoleRepository;
_userRoleRepository = userRoleRepository;
}
[HttpGet]
public async Task<IActionResult> GetAllUsersAsync()
{
var users = _userRepository.GetAllAsync();
var usersDto = users.ConvertToDto(unknow arguments)
}
}
And i am trying achieve it by using static DtoConverstion function
It looks like this
public static IEnumerable<ReturnUserDto> ConvertToDto(this IEnumerable<User> users,
IEnumerable<Role> Role)
{
var returnUserDto = (from user in users
select new ReturnUserDto
{
Id = user.Id,
Username = user.Username,
EmailAddress = user.EmailAddress,
Password = user.Password,
FirstName = user.FirstName,
LastName = user.LastName,
Roles = ?(Something like Role.name)
})
}
How do I achieve it? I understand that I need to use user_roles to get roles from it for a specific user, then add it to DtoConvertion function. I am just not sure how to do it.

Answer 1

Can do it multiple ways.One way is to use the Include() and ThenInclude() option
Instead of _userRepository.GetAllAsync(), add a new method which will get the list of Users along with User Roles and its Roles with it. It will be something like
context.Users
.Include(u => u.UserRoles)
.ThenInclude(u => u.Role).ToList()
Then, in the convert method, something like
public static IEnumerable<ReturnUserDto> ConvertToDto(this IEnumerable<User> users)
{
var returnUserDto = (from user in users
select new ReturnUserDto
{
Id = user.Id,
Username = user.Username,
EmailAddress = user.EmailAddress,
Password = user.Password,
FirstName = user.FirstName,
LastName = user.LastName,
Roles = user.UserRoles.Select(s => s.Role.Name).ToList()
})
}
Refer https://learn.microsoft.com/en-us/ef/ef6/querying/related-data if you are not familiar with the Include() method.
Hope this helps.