Object reference not set to an instance of an object

Hi. Error: NullReferenceException: Object reference not set to an instance of an object.

NullReferenceException: Object reference not set to an instance of an object.
DatingApp.API.Controllers.UsersController.GetUsers() in UsersController.cs, line 29

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NullReferenceException: Object reference not set to an instance of an object.
DatingApp.API.Controllers.UsersController.GetUsers() in UsersController.cs
+
        [HttpGet]
        public async Task<IActionResult> GetUsers()
        {
            var users = await _repo.GetUsers();

            var usersToReturn = _mapper.Map<IEnumerable<UserForListDto>>(users);
            return Ok(usersToReturn);
        }
        [HttpGet("{id}")]
        public async Task<IActionResult> GetUser(int id)
Microsoft.AspNetCore.Mvc.Internal.ActionMethodExecutor+TaskOfIActionResultExecutor.Execute(IActionResultTypeMapper mapper, ObjectMethodExecutor executor, object controller, object[] arguments)
System.Threading.Tasks.ValueTask<TResult>.get_Result()
Microsoft.AspNetCore.Mvc.Internal.ControllerActionInvoker.InvokeActionMethodAsync()
Microsoft.AspNetCore.Mvc.Internal.ControllerActionInvoker.InvokeNextActionFilterAsync()
Microsoft.AspNetCore.Mvc.Internal.ControllerActionInvoker.Rethrow(ActionExecutedContext context)
Microsoft.AspNetCore.Mvc.Internal.ControllerActionInvoker.Next(ref State next, ref Scope scope, ref object state, ref bool isCompleted)
Microsoft.AspNetCore.Mvc.Internal.ControllerActionInvoker.InvokeInnerFilterAsync()
Microsoft.AspNetCore.Mvc.Internal.ResourceInvoker.InvokeNextResourceFilter()
Microsoft.AspNetCore.Mvc.Internal.ResourceInvoker.Rethrow(ResourceExecutedContext context)
Microsoft.AspNetCore.Mvc.Internal.ResourceInvoker.Next(ref State next, ref Scope scope, ref object state, ref bool isCompleted)
Microsoft.AspNetCore.Mvc.Internal.ResourceInvoker.InvokeFilterPipelineAsync()
Microsoft.AspNetCore.Mvc.Internal.ResourceInvoker.InvokeAsync()
Microsoft.AspNetCore.Routing.EndpointMiddleware.Invoke(HttpContext httpContext)
Microsoft.AspNetCore.Routing.EndpointRoutingMiddleware.Invoke(HttpContext httpContext)
Microsoft.AspNetCore.Authentication.AuthenticationMiddleware.Invoke(HttpContext context)
Microsoft.AspNetCore.Diagnostics.DeveloperExceptionPageMiddleware.Invoke(HttpContext context)`

`at DatingApp.API.Controllers.UsersController.GetUsers() in H:\Projects\DatingApp.API\Controllers\UsersController.cs:line 29
   at Microsoft.AspNetCore.Mvc.Internal.ActionMethodExecutor.TaskOfIActionResultExecutor.Execute(IActionResultTypeMapper mapper, ObjectMethodExecutor executor, Object controller, Object[] arguments)
   at System.Threading.Tasks.ValueTask`1.get_Result()
   at Microsoft.AspNetCore.Mvc.Internal.ControllerActionInvoker.InvokeActionMethodAsync()
   at Microsoft.AspNetCore.Mvc.Internal.ControllerActionInvoker.InvokeNextActionFilterAsync()
   at Microsoft.AspNetCore.Mvc.Internal.ControllerActionInvoker.Rethrow(ActionExecutedContext context)
   at Microsoft.AspNetCore.Mvc.Internal.ControllerActionInvoker.Next(State& next, Scope& scope, Object& state, Boolean& isCompleted)
   at Microsoft.AspNetCore.Mvc.Internal.ControllerActionInvoker.InvokeInnerFilterAsync()
   at Microsoft.AspNetCore.Mvc.Internal.ResourceInvoker.InvokeNextResourceFilter()
   at Microsoft.AspNetCore.Mvc.Internal.ResourceInvoker.Rethrow(ResourceExecutedContext context)
   at Microsoft.AspNetCore.Mvc.Internal.ResourceInvoker.Next(State& next, Scope& scope, Object& state, Boolean& isCompleted)
   at Microsoft.AspNetCore.Mvc.Internal.ResourceInvoker.InvokeFilterPipelineAsync()
   at Microsoft.AspNetCore.Mvc.Internal.ResourceInvoker.InvokeAsync()
   at Microsoft.AspNetCore.Routing.EndpointMiddleware.Invoke(HttpContext httpContext)
   at Microsoft.AspNetCore.Routing.EndpointRoutingMiddleware.Invoke(HttpContext httpContext)
   at Microsoft.AspNetCore.Authentication.AuthenticationMiddleware.Invoke(HttpContext context)
   at Microsoft.AspNetCore.Diagnostics.DeveloperExceptionPageMiddleware.Invoke(HttpContext context)

AutoMapperProfiles.cs:

using System.Linq;
using AutoMapper;
using DatingApp.API.Dtos;
using DatingApp.API.Models;

namespace DatingApp.API.Helpers
{
    public class AutoMapperProfiles : Profile
    {
        public AutoMapperProfiles()
        {
            AllowNullCollections = true;

            CreateMap<User, UserForListDto>()
                .ForMember(dest => dest.PhotoUrl, opt => {
                    opt.MapFrom(src => src.Photos.FirstOrDefault(p => p.IsMain).Url);
                })
                .ForMember(dest => dest.Age, opt =>{
                    opt.MapFrom(src => src.DateOfBirth.CalculateAge());
                });

            CreateMap<User, UserForDetailDto>()
                .ForMember(dest => dest.PhotoUrl, opt => {
                    opt.MapFrom(src => src.Photos.FirstOrDefault(p => p.IsMain).Url);
                })
                .ForMember(dest => dest.Age, opt =>{
                    opt.MapFrom(src => src.DateOfBirth.CalculateAge());
                });

            CreateMap<Photo, PhotosForDetailDto>();
        }
    }
}

UserForListDto.cs:

using System;

namespace DatingApp.API.Dtos
{
    public class UserForListDto
    {
        public int Id { get; set; }

        public string Username { get; set; }

        public string Gender { get; set; }

        public int Age { get; set; }

        public string KnownAs { get; set; }

        public DateTime Created { get; set; }

        public DateTime LastActive { get; set; }

        public string City { get; set; }

        public string Country { get; set; }

        public string PhotoUrl { get; set; }
    }
}

PhotosForDetailDto.cs

using System;

namespace DatingApp.API.Dtos
{
    public class PhotosForDetailDto
    {
        public int Id { get; set; }

        public string Url { get; set; }

        public string Description { get; set; }

        public DateTime DateAdded { get; set; }

        public bool IsMain { get; set; }
    }
}

Photo.cs:

using System;

namespace DatingApp.API.Models
{
    public class Photo
    {
        public int Id { get; set; }

        public string Url { get; set; }

        public string Description { get; set; }

        public DateTime DateAdded { get; set; }

        public bool IsMain { get; set; }

        public User User { get; set; }

        public int UserId { get; set; }
    }
}

User.cs

using System;
using System.Collections.Generic;

namespace DatingApp.API.Models
{
    public class User
    {
        public int Id { get; set; }

        public string Username { get; set; }

        public byte[] PasswordHash { get; set; }

        public byte[] PasswordSalt { get; set; }

        public string Gender { get; set; }

        public DateTime DateOfBirth { get; set; }

        public string KnownAs { get; set; }

        public DateTime Created { get; set; }

        public DateTime LastActive { get; set; }

        public string Introduction { get; set; }

        public string LookingFor { get; set; }

        public string Interests { get; set; }

        public string City { get; set; }

        public string Country { get; set; }

        public ICollection<Photo> Photos { get; set; }
    }
}

Extensions.cs:

using System;
using Microsoft.AspNetCore.Http;

namespace DatingApp.API.Helpers
{
    public static class Extensions
    {
        public static void AddApplicationError(this HttpResponse response, string message)
        {
            response.Headers.Add("Application-Error", message);
            response.Headers.Add("Access-Control-Expose-Headers", "Application-Error");
            response.Headers.Add("Access-Control-Allow-Origin", "*");
        }

        public static int CalculateAge(this DateTime theDateTime)
        {
            var age = DateTime.Today.Year - theDateTime.Year;
            if (theDateTime.AddYears(age) > DateTime.Today) {
                age--;
            }

            return age;
        }
    }
}

IDatingRepository.cs:

using System.Collections.Generic;
using System.Threading.Tasks;
using DatingApp.API.Models;

namespace DatingApp.API.Data
{
    public interface IDatingRepository
    {
        void Add<T>(T entity) where T : class;

        void Delete<T>(T entity) where T : class;

        Task<bool> SaveAll();

        Task<IEnumerable<User>> GetUsers();

        Task<User> GetUser(int id);
    }
}

DatingRepository.cs:

using System.Collections.Generic;
using System.Threading.Tasks;
using AutoMapper;
using DatingApp.API.Models;
using Microsoft.EntityFrameworkCore;

namespace DatingApp.API.Data
{
    public class DatingRepository : IDatingRepository
    {
        private readonly DataContext _context;
        private readonly IMapper _mapper;
        public DatingRepository(DataContext context, IMapper mapper)
        {
            _context = context;
            _mapper = mapper;
        }

        public void Add<T>(T entity) where T : class
        {
            _context.Add(entity);
        }

        public void Delete<T>(T entity) where T : class
        {
            _context.Remove(entity);
        }

        public async Task<bool> SaveAll()
        {
            return await _context.SaveChangesAsync() > 0;
        }

        public async Task<IEnumerable<User>> GetUsers()
        {
            var users = await _context.Users.Include(p => p.Photos).ToListAsync();

            return users;
        }

        public async Task<User> GetUser(int id)
        {
            var user = await _context.Users.Include(p => p.Photos)
                .FirstOrDefaultAsync(u => u.Id == id);

            return user;
        }
    }
}

digitopoi / DatingApp.API

Object reference not set to an instance of an object #1