Unless
Quote:
CreateOfficeInvoice
is automatically generated, why can't you add code here to do what you wish (since it seems you have everything you need here already) - you need the CreateOfficeInvoice to succeed, but after that the world's your oyster.
I guess there has to be some sort of referential integrity here ... can
public ICollection<CustomerInvoice> CustomerInvoices { get; set; } = new List<CustomerInvoice>();
be an observableCollection maybe ? that way adding a new CustomerInvoice automatically triggers updating of the MedicineStore table