Automapper - POST / PUT entity nesting hierarchy - asp.net-core

Question

I would like to use DTOs and AutoMapper to POST and PUT an entity containing a List of nested entities, having a hierarchy.
Sample :
A company has a list of employees. In this list of employees can have a manager which is also an employee of the same company.
public class Company {
public int Id { get; set; }
public List<Employee> Employees { get; set; }
}
public class Employee {
public int Id { get; set; }
public Company Company { get; set; }
public int CompanyId { get; set; }
public Employee Manager { get; set; }
public int? ManagerId { get; set; }
}
I'd like to create a DTO which is able to POST and UPDATE a Company creating/updating/removing and changing relations between employees.
How would you do knowing that some employees can have no Id yet because they are newly created but are parents of other employees ?
Thanks in advance for the help.
Precision : i use dot net core 2.2, Entity Framework Core and AutoMapper.

Answer 1

You can do this as below.
public class CompanyDto {
public int Id { get; set; }
//Below line cannot exist here, otherwise it will create circular references
//public List<Employee> Employees { get; set; }
}
public class EmployeeDto {
public int Id { get; set; }
public Company Company { get; set; }
public int CompanyId { get; set; }
public Employee Manager { get; set; }
public int? ManagerId { get; set; }
}
After this, you can create your mappings in automapper configuration for Company -> CompanyDto(and reverse map) and Employee to EmployeeDto(and reverse map).
Now, for handling the case of new manager with existing employee, you do either of the following in your repository(with entity objects, not DTO's)
Create a new employee and then update the existing employees with the newly generated employee id in your repository
Or, get all the employees you want to update in your repository(load in context), add the new employee in the context with EntityState.Added. Now, assign the manager of employees you have fetched with the reference of new employee and save your context