I am working on an API and am having problems with making multiple calls to a service and it's different methods, I have each method creating and using new DBContext (or at least that's the intention), but after the first service call the others complain that the DBContext has been disposed, I was hoping you could point me in the right direction, because as far as I can see I am creating a new context for each of these calls - obviously I am doing something wrong here, any help would be much appreciated.
The actual error I am getting is "Cannot access a disposed object."
I know I can maybe pull the db interaction and context creation code out of the service and into the controller method here (it's a simplified example), but will need to use more services in other parts of the application and have encountered the problem there also, so would like to try and identify what is causing my problem in this example so that I can apply the fix elsewhere.
Here are the simplified classes involved.
public class UserController : Controller
{
private readonly IUserService userService;
public UserController(IUserService userService)
{
this.userService = userService;
}
[HttpPost]
[ActionName("PostUserDetails")]
public async Task<IActionResult> PostUserDetails([FromBody]UserDetailsContract userDetailsContract)
{
// this call is fine
var user = await userService.GetUserByCode(userDetailsContract.Code);
if (user == null)
{
return BadRequest("User not found");
}
// this call fails with the object disposed error
var userDetails = await userService.GetUserDetailsByCode(userDetailsContract.Code);
if (userDetails != null)
{
return BadRequest("UserDetails already exists");
}
// .. go on to save new entity
return Ok();
}
}
public class UserService : IUserService
{
private readonly IDatabaseFactory databaseFactory;
public UserService(IDatabaseFactory databaseFactory)
{
this.databaseFactory = databaseFactory;
}
public async Task<User> GetUserByCode(string code)
{
using (var db = databaseFactory.Create())
{
return await db.Users.GetByCode(code);
}
}
public async Task<IEnumerable<UserDetail>> GetUserDetailsByCode(string code)
{
using (var db = databaseFactory.Create())
{
return await db.UserDetails.GetByCode(code);
}
}
}
public class ApiDbContext : DbContext, IApiDbContext
{
public DbSet<User> Users { get; set; }
public DbSet<UserDetail> UserDetails { get; set; }
protected override void OnConfiguring(DbContextOptionsBuilder optionsBuilder)
{
optionsBuilder.UseSqlServer(@"Server=192.168.1.1;Database=dbname;User Id=user; Password=pwd; MultipleActiveResultSets=True;");
}
}
public class DatabaseFactory : IDatabaseFactory
{
public IApiDatabase Create()
{
return new ApiDatabase(new ApiDbContext());
}
}
public class ApiDatabase : RepositoriesBase, IApiDatabase
{
private IUserRepository userRepository;
private IUserDetailsRepository userDetailsRepository;
public ApiDatabase(ApiDbContext context) : base(context)
{
}
public IUserRepository Users => userRepository ?? (userRepository = new UserRepository(context));
public IUserDetailsRepository UserExchange => userDetailsRepository ?? (userDetailsRepository = new UserDetailsRepository(context));
}
public abstract class RepositoriesBase : IRepositories
{
internal readonly ApiDbContext context;
private bool isDisposing;
protected RepositoriesBase(ApiDbContext context)
{
}
public void Dispose()
{
if (!isDisposing)
{
isDisposing = true;
context?.Dispose();
}
}
public Task SaveChanges() => context.SaveChangesAsync();
}
public class UserRepository : Repository<User>, IUserRepository
{
public UserRepository(ApiDbContext context) : base(context)
{
}
public async Task<User> GetByCode(string code)
{
return Filter(x => x.code == code).Result.FirstOrDefault();
}
}
public class UserDetailsRepository : Repository<UserDetail>, IUserDetailRepository
{
public UserExchangeRepository(ApiDbContext context) : base(context)
{
}
public async Task<IEnumerable<UserDetail>> GetByUserId(int userId)
{
return await Filter(x => x.UserId == userId);
}
}
public class Repository<T> : IRepository<T> where T : class, IEntity
{
private readonly ApiDbContext context;
public Repository(ApiDbContext context) => this.context = context;
public async Task Add(T entity)
{
context.Set<T>().Add(entity);
}
public async Task Add(IEnumerable<T> entities)
{
foreach (var entity in entities)
{
context.Set<T>().Add(entity);
}
}
public async Task Delete(T entity)
{
context.Set<T>().Remove(entity);
}
public async Task Delete(IEnumerable<T> entities)
{
foreach (var entity in entities)
{
context.Set<T>().Remove(entity);
}
}
public async Task Delete(int id)
{
var entityToDelete = context.Set<T>().FirstOrDefault(e => e.Id == id);
if (entityToDelete != null)
{
context.Set<T>().Remove(entityToDelete);
}
}
public async Task Update(T entity)
{
context.Set<T>().Update(entity);
}
public async Task Edit(T entity)
{
var editedEntity = context.Set<T>().FirstOrDefault(e => e.Id == entity.Id);
editedEntity = entity;
}
public async Task<IEnumerable<T>> GetAll(Expression<Func<T, bool>> predicate = null)
{
var query = context.Set<T>().Include(context.GetIncludePaths(typeof(T)));
if (predicate != null)
{
query = query.Where(predicate);
}
return await query.ToListAsync();
}
public async Task<T> GetById(int id)
{
return context.Set<T>().FirstOrDefault(e => e.Id == id);
}
public async Task<IEnumerable<T>> Filter()
{
return context.Set<T>();
}
public virtual async Task<IEnumerable<T>> Filter(Func<T, bool> predicate)
{
return context.Set<T>().Where(predicate);
}
public async Task SaveChanges() => context.SaveChanges();
}
In my DI config I have DatabaseFactory and UserService defined as singletons.
Error: "Cannot access a disposed object."
More error details: " at Microsoft.EntityFrameworkCore.DbContext.CheckDisposed() at Microsoft.EntityFrameworkCore.DbContext.get_DbContextDependencies()
at Microsoft.EntityFrameworkCore.DbContext.get_Model() at Microsoft.EntityFrameworkCore.Internal.InternalDbSet1.get_EntityType() at Microsoft.EntityFrameworkCore.Internal.InternalDbSet1.get_EntityQueryable() at Microsoft.EntityFrameworkCore.Internal.InternalDbSet1.System.Collections.Generic.IEnumerable<TEntity>.GetEnumerator() at System.Linq.Enumerable.WhereEnumerableIterator1.MoveNext() at System.Linq.Enumerable.Any[TSource](IEnumerable1 source, Func2 predicate) at App.Api.Controllers.UserController.PostUserDetail(UserDetailContract userDetailContract) in D:\Repositories\application\src\App\Api\Controllers\UserController.cs:line 89"
Thank you
