Роман

set {
                  base.IsFormReadyToSend == value
            }

class User
{
    public int Id {get; set;}

    public UserGrop UserGroup {get; set;}
}

class UserGroup
{
    public int Id {get; set;}

    public User User {get; set;}
}

class UserGroup
{

    public int UserId {get; set;}
    [JsonIgnore]
    public User User {get; set;}
}

services.AddMvc()
    .AddJsonOptions(opt =>
    {
        opt.SerializerSettings.PreserveReferencesHandling = PreserveReferencesHandling.Objects;
    });

private List<Job> _jobs;
public List<Job> Jobs
{
    get {return _jobs;}
    set {
                _jobs = value;
                OnPropertyChanged("Jobs");        
    }
}

if (context.entity.Any( x=>x.id) {
}
else {
}