Entity Framework: How to query (LINQ) for data ->child-> 4 grandchildren - entity-framework

Question

I have 4 classes like that:
Organization1:
Contact 1:
Phones:
phone1
phone2
Addresses:
address1
address2
Bankdata:
bankdata1
bankdata2
Contact 2:
Phones:
phone1
phone2
Addresses:
address1
address2
Bankdata:
bankdata1
bankdata2
Contact 3:
Phones:
phone1
phone2
Addresses:
address1
address2
Bankdata:
bankdata1
bankdata2
Organization 2:
... and so on...
In order to grab the list of Organizations with all its contacts and each contact including JUST the phone1 (where main == true), address1 and bankdata1 I have written the following inside Entity Framework a query:
...
public class ContactManagementRepository : IContactManagementRepository
{
public IEnumerable<Organization> getAllOrganizations()
{
return _context.Organizations
.OrderBy(o => o.organizationName)
.Include(o => o.Contacts)
.ToList();
}
...
But I just get ONE Organization, and no contacts.
A tried a second attempt like this:
public class ContactManagementRepository : IContactManagementRepository
{
public IEnumerable<Organization> getAllOrganizations()
{
return _context.Organizations.ToList();
}
...
It returns all the organizations, but not data under the tree (contact->phones, etc)
A third attempt (very bad for performance) was to get ALL the organizations and loop through using getorganizationsbyID and get the info of each one like this:
...
public Organization GetOrganizationById(Guid Id)
{
return _context.Organizations
.Include(o => o.Contacts)
.ThenInclude(c => c.Phone.main == true)
.Where(o => o.Id == Id)
.FirstOrDefault();
}
...
But it just get the organization with JUST ONE CONTACT (the first one) and not phones, address or bankdata. The method "ThenInclude" does not accept a second call. It means accept just one child under contact, but not several children.
Here are my model classes:
Organization class:
public class Organization
{
public Organization() { }
private Organization(DateTime dateCreated)
{
this.dateCreated = DateTime.Now;
Contacts = new List<Contact>();
}
public Guid Id { get; set; }
public DateTime dateCreated { get; set; }
public string organizationName { get; set; }
public string organizationType { get; set; }
public string web { get; set; }
// Contacts
public ICollection<Contact> Contacts { get; set; }
}
Contact class:
public class Contact
{
public Contact() { }
private Contact(DateTime dateCreated)
{
this.dateCreated = DateTime.Now;
Phones = new List<Phone>();
Addresses = new List<Address>();
Bankdatas = new List<Bankdata>();
}
public Guid Id { get; set; }
public DateTime dateCreated { get; set; }
public string firstName { get; set; }
public string lastName { get; set; }
public string email { get; set; }
public Guid OrganizationId { get; set; }
[ForeignKey("OrganizationId")]
public virtual Organization Organization { get; set; }
public virtual ICollection<Phone> Phones { get; set; }
public virtual ICollection<Address> Addresses { get; set; }
public virtual ICollection<Bankdata> Bankdatas { get; set; }
}
Phone class (same structure for addresses and bankdata)
public class Phone
{
public Guid Id { get; set; }
public DateTime dateCreated { get; set; }
public string phone { get; set; }
public bool main { get; set; }
// Foreign Key for Contacts
public Guid ContactId { get; set; }
//Related Organization entity
[ForeignKey("ContactId")]
public virtual Contact Contact { get; set; }
}
Database is created with the PK and FK in correctly in place (code-first)
And now I am lost. Does anybody could help with this?
How do I query (LINQ) for organization -> child -> 4 grandchildren ?
I have read literally dozens of threads here and follow tutorials in Udemy and Pluralsight without success.
EDIT
# Hadi Hassan
I followed your instructions, I created new classes OrganizationDTO, ContactDTO, AddressDTO, PhoneDTO and BankdataDTO.
I created the DTO for Bank, Phone and address because even if am sure just one is main (there is a radio button at the front end) I still will need the whole list when I get the contactsdetails.html. It will allows me to make searches by country-code and so on.
I have changed, as per your advice, but it dd not even compile. I get error telling:
*DbSet<Organization>ContactManagement.Context.Organizations {get; set;}
Cannot assign method group to an implicitly-typed variable.*
I have decided to test changing the Context class like this:
DBSet. So I changes all DBset properties with the suffix DTO. Like this:
public DbSet<OrganizationDTO> OrganizationsDTO { get; set; }
public DbSet<ContactDTO> ContactsDTO { get; set; }
public DbSet<BankdataDTO> BankdatasDTO { get; set; }
public DbSet<AddressDTO> AddressesDTO { get; set; }
public DbSet<PhoneDTO> PhonesDTO { get; set; }
But the I have got copilations error everywhere.

Answer 1

Best way to get your data is by relying on the DTO
so your code will appear like this
public class OrganizationDTO
{
public OrganizationDTO()
{
Contacts = new List<ContactDTO>();
}
public Guid Id{get;set;}
public string Name{get; set;}
// other needed properties goes here
public IList<ContactDTO> Contacts{get;set;}
}
public class ContactDTO
{
public ContactDTO
{
Phones = new List<PhoneDTO>();
Addresses = new List<AddressDTO>();
Banks = new List<BankDTO>();
}
public Guid Id{get;set;}
public string FirstName{get;set;}
public string LastName {get;set;}
// other required properties goes here
public IList<PhoneDTO> Phones {get;set;}
public IList<BankDTO> Banks{get;set;}
public IList<AddressDTO> Addresses{get;set;}
}
public class PhoneDTO
{
public Guid Id{get;set;}
public string Phone{get;set;}
}
public class AddressDTO
{
public Guid Id{get;set;}
public string Description{get;set;}
}
public class BankDTO
{
public Guid Id{get;set;}
public string Name{get;set;}
}
Your query then will look like
var query = _context.Organizations
.Select t=> new OrganizationDTO{
Id = t.Id,
Name = t.organizationName,
Contacts = t.Contacts.Select(c => new ContactDTO{
Id = c.Id,
FirstName = c.firstName,
LastName = c.lastName,
Phones = c.Phones.Where(p=>p.Main).Select(p=>new PhoneDTO{Id = p.Id, Phone= p.phone}),
Banks = c.Banks.Where(p=>p.Main).Select(p=>new BankDTO{Id = p.Id, Name= p.BankName}),
Addresses = c.Addressess.Where(p=>p.Main).Select(p=>new AddressDTO{Id = p.Id, Description= p.Description}),
})
}).OrderBy(t=>t.Name);
Implementing the DTO will provide many advantages for your data
Avoid Circular references
Return the required data and not all the object (Data Projection)
Allows you to combine many objects together to appear in same result, for example, in the solution I returned object BankDTO and PhoneDTO and AddressDTO which allows your to return list of object from these entities, but if you are sure that only one phone, bank , address is main, then you can instead define these data as properties in the class ContactDTO and by this you combined 4 entities data in one result.
Your ContactDTO will become as
public class ContactDTO
{
public Guid Id{get;set;}
public string FirstName{get;set;}
public string LastName{get;set;}
public string Phone{get;set;}
public string Bank{get;set;}
public string Address{get;set;}
}
and your code will be like
var query = _context.Organizations
.Select t=> new OrganizationDTO{
Id = t.Id,
Name = t.organizationName,
Contacts = t.Contacts.Select(c => new ContactDTO{
Id = c.Id,
FirstName = c.firstName,
LastName = c.lastName,
Phone = c.Phones.Where(p=>p.Main).Select(p=>p.phone).FirstOrDefault(),
Bank = c.Banks.Where(p=>p.Main).Select(p=>p.Name).FirstOrDefault(),
Address = c.Addressess.Where(p=>p.Main).Select(p=>p.Discreption).FirstOrDefault(),
})
}).OrderBy(t=>t.Name);
and in case you want to get the phone as object and not list, may be you want to get the benefit of the phone Id, you can instead of IList<PhoneDTO> to define directly PhoneDTO.
Hope this will help you