.net Core 3 / API / DI / Repository pattern - api

Question

I'm trying to create a web API in .net Core. I would like this API calls a DLL with repository design pattern implemented in it. In this whole thing I tried to use dependency injection but I have some issues to manage context for database in repository.
I would like than the context one new context per lifetime of a call to the API.
When I try to execute my code I have an exception at line CreateHostBuilder(args).Build().Run(); in Main.
This Exception is :
'Some services are not able to be constructed'
InvalidOperationException : Unable to resolve service for type 'BX_Security_AccessBase.Context.SecurityContext' while attempting to activate 'BX_Security_AccessBase.Repository.UsersRepository'.
I know the code is incomplete and won't work completely but at least it should break way later than actually. I think I made a mistake in the architecture.
There is a lot of code below but I couldn't isolate my problem.
Thank you everybody.
In my API I have :
Startup.cs
public class Startup
{
public Startup(IConfiguration configuration)
{
Configuration = configuration;
}
public IConfiguration Configuration { get; }
public void ConfigureServices(IServiceCollection services)
{
services.AddControllers();
services.AddScoped<IUsersRepository, UsersRepository>();
services.AddScoped<IUserService, UserService>();
}
public void Configure(IApplicationBuilder app, IWebHostEnvironment env)
{
if (env.IsDevelopment())
{
app.UseDeveloperExceptionPage();
}
app.UseHttpsRedirection();
app.UseRouting();
app.UseAuthorization();
app.UseEndpoints(endpoints =>
{
endpoints.MapControllers();
});
}
}
User.cs
public class User
{
public User() {}
public int UserId { get; set; }
public string LastName { get; set; }
public string FirstName { get; set; }
public DateTime Birthdate { get; set; }
}
UserService.cs
public class UserService : IUserService
{
private readonly AppSettings _appSettings;
private readonly IUsersRepository _userRepository;
public UserService(IOptions<AppSettings> appSettings, IUsersRepository userRepository)
{
_appSettings = appSettings.Value;
_userRepository = userRepository;
}
public IEnumerable<User> GetAll()
{
return _userRepository.GetAllUsers().Select(u=> new User());
}
}
IUserService.cs
public interface IUserService
{
public IEnumerable<User> GetAll();
}
AppSettings.cs
public class AppSettings
{
public string Secret { get; set; }
}
UsersController.cs
[Route("api/[controller]")]
[ApiController]
public class UsersController : ControllerBase
{
private IUserService _userService { get; }
public UsersController(IUserService userService)
{
_userService = userService;
}
[HttpGet]
public IActionResult GetAll()
{
var users = _userService.GetAll();
return Ok(users);
}
}
In the DLL I have :
SecurityContext.cs
public partial class SecurityContext : DbContext
{
public SecurityContext(DbContextOptions<SecurityContext> options) : base(options) { }
public DbSet<Users> Users { get; set; }
protected override void OnConfiguring(DbContextOptionsBuilder optionsBuilder)
{
if (!optionsBuilder.IsConfigured)
{
optionsBuilder.UseSqlServer("Data Source=; Database=BXDB; User Id=sa; Password=;");
}
}
protected override void OnModelCreating(ModelBuilder modelBuilder)
{
modelBuilder.Entity<Users>(entity =>
{
entity.HasKey(e => e.UserId).HasName("PK_User_UserId");
entity.ToTable("Users", "sec");
entity.Property(e => e.Birthdate).HasColumnType("date");
entity.Property(e => e.FirstName)
.HasMaxLength(50)
.IsUnicode(false);
entity.Property(e => e.LastName)
.HasMaxLength(50)
.IsUnicode(false);
});
OnModelCreatingPartial(modelBuilder);
}
partial void OnModelCreatingPartial(ModelBuilder modelBuilder);
}
Users.cs
public class Users
{
public Users() { }
public int UserId { get; set; }
public string LastName { get; set; }
public string FirstName { get; set; }
public DateTime Birthdate { get; set; }
}
IUsersRepository.cs
public interface IUsersRepository
{
public IQueryable<Users> GetAllUsers();
}
UsersRepository.cs
public class UsersRepository : IUsersRepository
{
public readonly SecurityContext _dbContext;
public UsersRepository(SecurityContext dbContext)
{
_dbContext = dbContext;
}
public IQueryable<Users> GetAllUsers()
{
return _dbContext.Users;
}
}

Answer 1

'Some services are not able to be constructed' InvalidOperationException : Unable to resolve service for type 'BX_Security_AccessBase.Context.SecurityContext' while attempting to activate 'BX_Security_AccessBase.Repository.UsersRepository'.
From the error , you should register the DbContext as a service as follows:
public void ConfigureServices(IServiceCollection services)
{
var connection = #"Server=(localdb)\mssqllocaldb;Database=BXDB;Trusted_Connection=True;ConnectRetryCount=0";
services.AddDbContext<DLL.Models.SecurityContext>(options => options.UseSqlServer(connection, x => x.MigrationsAssembly("DLL")));
services.AddControllers();
services.AddScoped<IUsersRepository, UsersRepository>();
services.AddScoped<IUserService, UserService>();
}