C# System.InvalidOperationException DisplayClass0_0 error while getting token-CodePudding

I need to get token when I register, but it gives me an error

Hello everyone.

I got that error when I was trying to register to my project on Postman:

(System.InvalidOperationException: An exception was thrown while attempting to evaluate the LINQ query parameter expression 'value(DataAccess.Concrete.EntityFramework.EfUserDal <>c__DisplayClass0_0).user.Id'. See the inner exception for more information.)

My UserManager is here:

using System.Collections.Generic;
using Business.Abstract;
using Core.Entities.Concrete;
using DataAccess.Abstract;

namespace Business.Concrete
{
    public class UserManager : IUserService
    {
        IUserDal _userDal;

        public UserManager(IUserDal userDal)
        {
            _userDal = userDal;
        }

        public List<OperationClaim> GetClaims(User user)
        {
            return _userDal.GetClaims(user);
        }

        public void Add(User user)
        {
            _userDal.Add(user);
        }

        public User GetByMail(string email)
        {
            return _userDal.Get(u => u.Email == email);
        }

    }
}

My AuthManager is here:

using Business.Abstract;
using Business.Constants;
using Core.Entities.Concrete;
using Core.Utilities.Results;
using Core.Utilities.Security.Hashing;
using Core.Utilities.Security.JWT;
using Entities.DTOs;

namespace Business.Concrete
{
    public class AuthManager : IAuthService
    {
        private IUserService _userService;
        private ITokenHelper _tokenHelper;

        public AuthManager(IUserService userService, ITokenHelper tokenHelper)
        {
            _userService = userService;
            _tokenHelper = tokenHelper;
        }

        public IDataResult<User> Register(UserForRegisterDto userForRegisterDto, string password)
        {
            byte[] passwordHash, passwordSalt;
            HashingHelper.CreatePasswordHash(password, out passwordHash, out passwordSalt);
            var user = new User
            {
                Email = userForRegisterDto.Email,
                FirstName = userForRegisterDto.FirstName,
                LastName = userForRegisterDto.LastName,
                PasswordHash = passwordHash,
                PasswordSalt = passwordSalt,
                Status = true
            };
            _userService.Add(user);
            return new SuccessDataResult<User>(user, Messages.UserRegistered);
        }

        public IDataResult<User> Login(UserForLoginDto userForLoginDto)
        {
            var userToCheck = _userService.GetByMail(userForLoginDto.Email);
            if (userToCheck == null)
            {
                return new ErrorDataResult<User>(Messages.UserNotFound);
            }

            if (!HashingHelper.VerifyPasswordHash(userForLoginDto.Password, userToCheck.PasswordHash, userToCheck.PasswordSalt))
            {
                return new ErrorDataResult<User>(Messages.PasswordError);
            }

            return new SuccessDataResult<User>(userToCheck, Messages.SuccessfulLogin);
        }

        public IResult UserExists(string email)
        {
            if (_userService.GetByMail(email) != null)
            {
                return new ErrorResult(Messages.UserAlreadyExists);
            }

            return new SuccessResult();
        }

        public IDataResult<AccessToken> CreateAccessToken(User user)
        {
            var claims = _userService.GetClaims(user);
            var accessToken = _tokenHelper.CreateToken(user, claims);
            return new SuccessDataResult<AccessToken>(accessToken, Messages.AccessTokenCreated);
        }
    }
}

My AuthController is here:

using System;
using System.Collections.Generic;
using System.Linq;
using System.Threading.Tasks;
using Business.Abstract;
using Entities.DTOs;
using Microsoft.AspNetCore.Http;
using Microsoft.AspNetCore.Mvc;

namespace WebAPI.Controllers
{
    [Route("api/[controller]")]
    [ApiController]
    public class AuthController : Controller
    {
        private IAuthService _authService;

        public AuthController(IAuthService authService)
        {
            _authService = authService;
        }

        [HttpPost("login")]
        public ActionResult Login(UserForLoginDto userForLoginDto)
        {
            var userToLogin = _authService.Login(userForLoginDto);
            if (!userToLogin.Success)
            {
                return BadRequest(userToLogin.Message);
            }

            var result = _authService.CreateAccessToken(userToLogin.Data);
            if (result.Success)
            {
                return Ok(result.Data);
            }

            return BadRequest(result.Message);
        }

        [HttpPost("register")]
        public ActionResult Register(UserForRegisterDto userForRegisterDto)
        {
            var userExists = _authService.UserExists(userForRegisterDto.Email);
            if (!userExists.Success)
            {
                return BadRequest(userExists.Message);
            }

            var registerResult = _authService.Register(userForRegisterDto,userForRegisterDto.Password);
            var result = _authService.CreateAccessToken(registerResult.Data);
            if (result.Success)
            {
                return Ok(result.Data);
            }

            return BadRequest(result.Message);
        }
    }
}

My EfUserDal is here:

using System.Collections.Generic;
using Core.DataAccess.EntityFramework;
using Core.Entities.Concrete;
using DataAccess.Abstract;
using System.Linq;

namespace DataAccess.Concrete.EntityFramework
{
    public class EfUserDal : EfEntityRepositoryBase<User,CarRentalContext>,IUserDal
    {
        public List<OperationClaim> GetClaims(User user)
        {
            using (CarRentalContext context = new CarRentalContext())
            {
                var result = from operationClaim in context.OperationClaims
                    join userOperationClaim in context.UserOperationClaims
                        on operationClaim.Id equals userOperationClaim.OperationClaimId
                    where userOperationClaim.UserId == user.Id
                    select new OperationClaim {Id = operationClaim.Id, Name = operationClaim.Name};
                return result.ToList();
            }
        }
    }
}

I need to get a token when I register. How can I fix this?

CodePudding user response：

You picked up the wrong lines from your stacktrace to focus on.

It states the following in the inner exception:

 System.NullReferenceException: Object reference not set to an instance of an object.
   at DataAccess.Concrete.EntityFramework.EfUserDal.GetClaims(User user) in /home/mert/Desktop/Project/ReCapProject/DataAccess/Concrete/EntityFramework/EfUserDal.cs:line 20

Which means you have a variable on line 20 in your EfUserDal which does not have a value at runtime.

Since the next line mentions ToList, I'm guessing result is null after evaluating the query. Use debugging to see what value each variable in your query is getting before it's evaluated. Probably one of them is null