Activities of "soulmate"

Hello, I hove following entities:

public class Provider : EntityBase
    {

        [Column(Order = 120)]
        public string Name { get; set; } 

        public virtual ICollection<Country> Countries { get; set; }

    }

    public class Country :EntityBase
    {
        [MaxLength(100)]
        public string Name { get; set; }

        [MaxLength(10)]
        public string Code { get; set; }

        
    }

And following configuration:

public class ProviderConfiguration : EntityTypeConfiguration<Provider>
    {
        public ProviderConfiguration()
        {
            HasMany(m => m.Countries)
                .WithMany()
                .Map(m =>
                {
                    m.MapLeftKey("ProviderId");
                    m.MapRightKey("CountryId");
                    m.ToTable("Provider_Countries");
                });
        }
    }

That means a provider can have several countries. The table in sql server look good and as far as I know that is the recommended method to build up many to many relationship. However, when I try to save the children only my provider entity is saved and the children are not saved to the "Provider_Countries" table:

public ProviderService(IRepository<Provider> providerRepository, IRepository<Country> countryRepository)
        {
            _providerRepository = providerRepository;
            _countryRepository = countryRepository;
        }
 

public async Task SaveAsync(Provider provider)
        {
            var entity = provider;


            var countriesToAdd = provider.Countries.ToList();

            //Clear existing entities
            entity.Countries.Clear();


            foreach (var countryToAdd in countriesToAdd)
            {
                var country = _countryRepository.Get(countryToAdd.Id);

                entity.Countries.Add(country);
            }
            _providerRepository.InsertOrUpdate(entity);


          
                await CurrentUnitOfWork.SaveChangesAsync();
         
        }

Based on the topics I found on the internet that is the recommended approach how to save a many to many relationship. Do you have any idea how I can save the child items?

Nevermind, I fixed it.

My code was

[System.Web.Http.HttpGet]
        [DontWrapResult]
        public async Task<ActionResult> Get()
        {
            var countrys = await _countryAppService.GetAllAsync();

            return Json(countrys, JsonRequestBehavior.AllowGet);
        }

However, because countrys is of type ListResultOutput<CountryViewModel> I need to change it to:

[System.Web.Http.HttpGet]
        [DontWrapResult]
        public async Task<ActionResult> Get()
        {
            var countrys = await _countryAppService.GetAllAsync();

            return Json(countrys.Items, JsonRequestBehavior.AllowGet);
        }

Hi, The attribute does not seem to help very much. I copied my controller from a working version of another project. My method returns: [{"Name":"Germany","Id":2}]

However, the same method with the DontWrapResult returns {"Items":[{"Name":"Germany","Id":2}]}